Role of leptin in hypothalamic-pituitary function

Expression of leptin and its long-form receptor in the porcine corpus luteum during pregnancy and the protective role of leptin in corpus luteum function invitro

Although the hormone leptin and its long-form receptor (LEPR) have been identified in the porcine ovary, their direct roles in mediating corpus luteum (CL) function in pregnant sows have not been clearly defined. In this study, we investigated leptin and LEPR expression in the porcine CL during pregnancy and evaluated the effect of the hormone on CL function in vitro. Leptin and LEPR were continuously expressed in the CL throughout pregnancy, and their expression patterns were generally similar, with higher levels in the early and middle stages of pregnancy and lower levels in the late stage. Immunohistochemical analysis revealed that both leptin and LEPR were predominantly localized in the luteal cells, with strong immunostaining observed in the early and middle stages CL and weak immunostaining in the late stage. Leptin 1-100 nM concentrations significantly increased the viability of cultured luteal cells (P < 0.05) and promoted their release of progesterone (P4) in a dose-dependent manner. Furthermore, leptin attenuated the prostaglandin F2α (PGF2α)-induced decreases in cell viability and P4 release. Additionally, leptin was found to have stimulatory effects on luteinizing hormone (LH) and prostaglandin E2 (PGE2) release but an inhibitory effect on PGF2α secretion. In conclusion, the presence of leptin and LEPR in the CL and the stimulatory effects of the hormone on the viability of luteal cells and their release of P4, LH, and PGE2 suggest that leptin has a positive regulatory effect on CL function in pregnant sows.

Exogenous visfatin suppresses pituitary gonadotrophins and stimulates testosterone secretion in a male mouse

Visfatin expression has been shown in the testis and pituitary. However, the role of visfatin in the pituitary and testis axis is fragmentary. Furthermore, no study has shown the effects of visfatin on the pituitary gonadotrophins and testicular steroid hormonal secretions in a male mouse. The present study has investigated the effects of exogenous visfatin (most likely a state of hypervisfatinemia) on the gonadotrophins, testosterone, estradiol, androstenedione, and progesterone in a male mouse. The exogenous visfatin was given for 35 days, which covers one spermatogenic cycle. The circulating testosterone was elevated after visfatin treatment, along with down-regulation of AR and steroidogenic markers in the testis. However, the expression of CYP17 was up-regulated in visfatin-treated testis. Visfatin treatment also elevated apoptosis in the different germ cells of the testis. The levels of circulating LH and FSH were also suppressed after visfatin treatment. The immunolocalization of AR exhibited decreased abundance in the pituitary of visfatin-treated mice; thus, it can be suggested that pituitary gonadotrophins secretion might be suppressed by direct action of visfatin rather than via elevated testosterone. In conclusion, our results showed that exogenous visfatin suppresses gonadotrophins and stimulates testicular testosterone secretions in a differential manner. Visfatin has inhibitory effects on pituitary gonadotrophins secretion and stimulatory effects on testosterone secretion from the testis. Thus, conditions similar to hypervisfatinemia likely impair the release of hormones from the pituitary and testis.

Neuropeptide Y at the crossroads of male reproductive functions in a seasonally breeding reptile, Hemidactylus flaviviridis

Neuropeptide Y (NPY) is known to be a key regulator of reproductive functions across vertebrates. Its role in the modulation of gonadotropin releasing hormone (GnRH) has been extensively explored in mammals and fishes. However, no such report exists in aves, amphibians, or reptiles. Hence, the present study aimed to develop an insight into reproductive phase-dependent expression and role of NPY in the diencephalon region of male wall lizards. Expression of ligand, npy, and its receptor, npyr varied across the annual reproductive cycle of Hemidactylus flaviviridis with the highest expression of both observed during recrudescence. Further, the diencephalon region of recrudescent wall lizards treated with NPY demonstrated an increased mRNA level of gnrh and its receptor, gnrhr. In addition, the current study also elucidates hormonal regulation of diencephalonic npy and npyr wherein neuropeptides like kisspeptin and substance P, the gonadotropin, FSH, as well as sex steroids, dihydrotestosterone (DHT) and 17β-estradiol (E2) inhibited npy and npyr expression in the diencephalon region of wall lizards. With regard to adipokines, leptin stimulated while nesfatin-1 inhibited diencephalonic npy and npyr expression. In conclusion, the current study is the first to present a comprehensive picture of reproductive phase-specific expression pattern, role, and hormonal regulation of neuropeptide Y in the diencephalon region of the male wall lizard, H. flaviviridis.

Proteomic and phosphoproteomic signatures of aging mouse liver

The liver is a metabolic powerhouse, crucial for regulating carbohydrates, fats, and protein metabolism. In this study, we conducted a comparative proteomic and phosphoproteomic analysis of aging mouse livers from young adults (3-4 months) and old (19-21 months) mice to identify age-related changes in liver proteins and phosphosites, which were linked to various metabolic pathways. In old mice, proteins associated with the "complement and coagulation cascade," "age-rage signaling in diabetic complications," and "biosynthesis of unsaturated fatty acids" were increased, while those linked to "oxidative phosphorylation," "steroid hormone biosynthesis," and "tryptophan metabolism" were decreased. Interestingly, aging was marked by a significant decrease in liver protein phosphorylation, with nearly 90% of significant phosphosites being downregulated. Pathway analysis of the downregulated phosphosites highlighted connections to "non-small cell lung cancer," "lysine degradation," "cell differentiation," and "glycerophospholipid metabolism." Decreased phosphorylation of several kinases that are linked to cell proliferation, particularly those in the MAPK signaling pathway, including Erk1, EGFR, RAF1, and BRAF was also observed highlighting their important role in the liver. This study identified an important relationship between proteins, phosphosites, and their connections to known as well as new pathways, expanding upon our current knowledge and providing a basis for future studies focused on age-related metabolic traits.

Leptin physiology and pathophysiology in energy homeostasis, immune function, neuroendocrine regulation and bone health

Since its discovery and over the past thirty years, extensive research has significantly expanded our understanding of leptin and its diverse roles in human physiology, pathophysiology and therapeutics. A prototypical adipokine initially identified for its critical function in appetite regulation and energy homeostasis, leptin has been revealed to also exert profound effects on the hypothalamic-pituitary-gonadal, thyroid, adrenal and growth hormone axis, differentially between animals and humans, as well as in regulating immune function. Beyond these roles, leptin plays a pivotal role in significantly affecting bone health by promoting bone formation and regulating bone metabolism both directly and indirectly through its neuroendocrine actions. The diverse actions of leptin are particularly notable in leptin-deficient animal models and in conditions characterized by low circulating leptin levels, such as lipodystrophies and relative energy deficiency. Conversely, the effectiveness of leptin is attenuated in leptin-sufficient states, such as obesity and other high-adiposity conditions associated with hyperleptinemia and leptin tolerance. This review attempts to consolidate 30 years of leptin research with an emphasis on its physiology and pathophysiology in humans, including its promising therapeutic potential. We discuss preclinical and human studies describing the pathophysiology of energy deficiency across organ systems and the significant role of leptin in regulating neuroendocrine, immune, reproductive and bone health. We finally present past proof of concept clinical trials of leptin administration in leptin-deficient subjects that have demonstrated positive neuroendocrine, reproductive, and bone health outcomes, setting the stage for future phase IIb and III randomized clinical trials in these conditions.

Dietary Fructose: A Literature Review of Current Evidence and Implications on Metabolic Health

With the increasing intake of dietary fructose, primarily from sucrose and sweetened beverages, metabolic illnesses such as type 2 diabetes mellitus, hypertension, fatty liver disease, dyslipidemia, and hyperuricemia have become more prevalent worldwide, and there is also growing concern about the development of malignancies. These negative health impacts have been validated in various meta-analyses and randomized controlled trials. In contrast, the naturally occurring fructose found in fruits and vegetables contains only a minimal amount of fructose and, when consumed in moderation, may be a healthier choice. This review focuses on the biology of fructose, including its dietary sources, the physiology of its metabolism, and the pathological basis of various disorders related to high dietary fructose intake.

Hippocampal Leptin Resistance and Cognitive Decline: Mechanisms, Therapeutic Strategies and Clinical Implications

Background: Leptin, an adipokine essential for regulating energy balance, exerts important effects on brain function, notably within the hippocampus, a region integral to learning and memory. Leptin resistance, characterized by diminished responsiveness to elevated leptin levels, disrupts hippocampal function and exacerbates both obesity and cognitive impairments. Scope: This review critically examines how leptin resistance impairs hippocampal synaptic plasticity processes, specifically affecting long-term potentiation (LTP) and long-term depression (LTD), which are crucial for cognitive performance. Findings: Recent research highlights that leptin resistance disrupts N-methyl-D-aspartate (NMDA) receptor dynamics and hippocampal structure, leading to deficits in spatial learning and memory. Additionally, high-fat diets (HFDs), which contribute to leptin resistance, further deteriorate hippocampal function. Potential therapeutic strategies, including leptin sensitizers, show promise in mitigating brain disorders associated with leptin resistance. Complementary interventions such as caloric restriction and physical exercise also enhance leptin sensitivity and offer potential benefits to alleviating cognitive impairments. Aims of the review: This review synthesizes recent findings on the molecular pathways underlying leptin resistance and its impact on synaptic transmission and plasticity in the hippocampus. By identifying potential therapeutic targets, this work aims to provide an integrated approach for addressing cognitive deficits in obesity, ultimately improving the quality of life for affected individuals.

Relative Energy Deficiency in Sport (REDs): Endocrine Manifestations, Pathophysiology and Treatments

Research on lean, energy-deficient athletic and military cohorts has broadened the concept of the Female Athlete Triad into the Relative Energy Deficiency in Sport (REDs) syndrome. REDs represents a spectrum of abnormalities induced by low energy availability (LEA), which serves as the underlying cause of all symptoms described within the REDs concept, affecting exercising populations of either biological sex. Both short- and long-term LEA, in conjunction with other moderating factors, may produce a multitude of maladaptive changes that impair various physiological systems and adversely affect health, well-being, and sport performance. Consequently, the comprehensive definition of REDs encompasses a broad spectrum of physiological sequelae and adverse clinical outcomes related to LEA, such as neuroendocrine, bone, immune, and hematological effects, ultimately resulting in compromised health and performance. In this review, we discuss the pathophysiology of REDs and associated disorders. We briefly examine current treatment recommendations for REDs, primarily focusing on nonpharmacological, behavioral, and lifestyle modifications that target its underlying cause-energy deficit. We also discuss treatment approaches aimed at managing symptoms, such as menstrual dysfunction and bone stress injuries, and explore potential novel treatments that target the underlying physiology, emphasizing the roles of leptin and the activin-follistatin-inhibin axis, the roles of which remain to be fully elucidated, in the pathophysiology and management of REDs. In the near future, novel therapies leveraging our emerging understanding of molecules and physiological axes underlying energy availability or lack thereof may restore LEA-related abnormalities, thus preventing and/or treating REDs-related health complications, such as stress fractures, and improving performance.

Visfatin (NAMPT) affects global gene expression in porcine anterior pituitary cells during the mid-luteal phase of the oestrous cycle

BACKGROUND

The pituitary belongs to the most important endocrine glands involved in regulating reproductive functions. The proper functioning of this gland ensures the undisturbed course of the oestrous cycle and affects the female's reproductive potential. It is believed that visfatin, a hormone belonging to the adipokine family, may regulate reproductive functions in response to the female's metabolic state. Herein we verified the hypothesis that suggests a modulatory effect of visfatin on the anterior pituitary transcriptome during the mid-luteal phase of the oestrous cycle.

RESULTS

RNA-seq analysis of the porcine anterior pituitary cells revealed changes in the expression of 202 genes (95 up-regulated and 107 down-regulated in the presence of visfatin, when compared to the non-treated controls), assigned to 318 gene ontology terms. We revealed changes in the frequency of alternative splicing events (235 cases), as well as long noncoding RNA expression (79 cases) in the presence of the adipokine. The identified genes were associated, among others, with reproductive system development, epithelial cell proliferation, positive regulation of cell development, gland morphogenesis and cell chemotaxis.

CONCLUSIONS

The obtained results indicate a modulatory influence of visfatin on the regulation of the porcine transcriptome and, in consequence, pituitary physiology during the mid-luteal phase of the oestrous cycle.

Topiramate treatment during adolescence induces short and long-term alterations in the reproductive system of female rats

Topiramate (TPM) is an antiepileptic drug used for treating epilepsy in children, and migraine in teenagers. In this context, preclinical studies with adult female rats observed reproductive system abnormalities following treatment with TPM. Additionally, exposure to endocrine disruptors during developmental plasticity periods, such as childhood and adolescence, may influence characteristics in the adult individual. This study evaluated whether treatment with TPM during developmental periods influences the reproductive system of female rats either immediately or in adult life. Female Wistar rats were treated with TPM (41 mg/Kg/day) by oral gavage from postnatal day (PND) 16-28, or PND 28-50, which correspond to childhood and adolescence, respectively, and euthanized either 24 h after the final administration or during adulthood. Treatment with TPM during adolescence induced short-term increase in uterus and ovary weights and reduction in endometrial stroma thickness. Adult animals treated during adolescence displayed reduced primordial ovarian follicles' numbers, and increased primary and pre-antral ovarian follicles' numbers. Treatment during childhood induced no short or long-term differences. These results indicate TPM treatment during adolescence is capable of inducing short and long-term alterations on the reproductive system of female Wistar rats.

Mechanisms of probiotic modulation of ovarian sex hormone production and metabolism: a review

Sex hormones play a pivotal role in the growth and development of the skeletal, neurological, and reproductive systems. In women, the dysregulation of sex hormones can result in various health complications such as acne, hirsutism, and irregular menstruation. One of the most prevalent diseases associated with excess androgens is polycystic ovary syndrome with a hyperandrogenic phenotype. Probiotics have shown the potential to enhance the secretion of ovarian sex hormones. However, the underlying mechanism of action remains unclear. Furthermore, comprehensive reviews detailing how probiotics modulate ovarian sex hormones are scarce. This review seeks to shed light on the potential mechanisms through which probiotics influence the production of ovarian sex hormones. The role of probiotics across various biological axes, including the gut-ovarian, gut-brain-ovarian, gut-liver-ovarian, gut-pancreas-ovarian, and gut-fat-ovarian axes, with a focus on the direct impact of probiotics on the ovaries via the gut and their effects on brain gonadotropins is discussed. It is also proposed herein that probiotics can significantly influence the onset, progression, and complications of ovarian sex hormone abnormalities. In addition, this review provides a theoretical basis for the therapeutic application of probiotics in managing sex hormone-related health conditions.

Hypothalamic-Ovarian axis and Adiposity Relationship in Polycystic Ovary Syndrome: Physiopathology and Therapeutic Options for the Management of Metabolic and Inflammatory Aspects

PURPOSE OF REVIEW

The goal of the present review is to address the main adiposity-related alterations in Polycystic Ovary Syndrome (PCOS) focusing on hypothalamic-pituitary-ovarian (H-P-O) axis and to provide an overview of nutraceutical and pharmacological therapeutic strategies.

RECENT FINDINGS

Female reproduction is a complex and delicate interplay between neuroendocrine signals involving the H-P-O axis. Elements that disrupt the balance of these interactions can lead to metabolic and reproductive disorders, such as PCOS. This disorder includes menstrual, metabolic, and biochemical abnormalities as well as hyperandrogenism, oligo-anovulatory menstrual cycles, insulin resistance, and hyperleptinemia which share an inflammatory state with other chronic diseases. Moreover, as in a self-feeding cycle, high androgen levels in PCOS lead to visceral fat deposition, resulting in insulin resistance and hyperinsulinemia, further stimulating ovarian and adrenal androgen production. In fact, regardless of age and BMI, women with PCOS have more adipose tissue and less lean mass than healthy women. Excessive adiposity, especially visceral adiposity, is capable of affecting female reproduction through direct mechanisms compromising the luteal phase, and indirect mechanisms as metabolic alterations able to affect the function of the H-P-O axis. The intricate crosstalk between adiposity, inflammatory status and H-P-O axis function contributes to the main adiposity-related alterations in PCOS, and alongside currently available hormonal treatments, nutraceutical and pharmacological therapeutic strategies can be exploited to treat these alterations, in order to enable a more comprehensive synergistic and tailored treatment.

Sequence identification and expression characterization of leptin in the spotted scat, Scatophagus argus

Scatophagus argus is an important marine culture fish in South and South-East Asia, including Southeast coastal areas of China. Artificial propagation technology for S. argus is not optimum; thus further studies on its reproduction biology are required. Although previous studies have shown that leptin (Lep) can regulate fish reproduction, the role of lep genes in S. argus is unknown. Herein, in silico analysis showed that S. argus has two lep genes (lepa and lepb). Protein 3D-structure prediction showed that Lepa has four α-helices (similar to mammals), while Lepb only has three. Tissue distribution analysis showed that lepa is highly expressed in the liver, whereas lepb was not detected in any tissue. Notably, lepr was expressed in all tissues. Lepa mRNA expression levels in the liver and serum Lep, estradiol (E2) and vitellogenin (Vtg) levels of female fish were significantly higher in ovaries at stage IV than in ovaries at stage II. Serum E2 levels were significantly positively correlated with Vtg levels in female fish at different development stages, while serum E2 was not correlated with Lep levels. Consistently, in vitro incubation of the liver with E2 significantly up-regulated vtga, while it did not affect lepa expression. Recombinant Lep (10 nM) significantly up-regulated chicken gonadotropin-releasing hormone (cGnRH/GnRH-II) in the hypothalamus and GnRH receptor (GnRHR) and luteinizing hormone beta (Lhb) in the pituitary. These results suggest that lepa regulates female reproduction in S. argus.

Evaluation of the Utility of Seminal Plasma Resistin and Leptin in Predicting Successful Surgical Sperm Retrieval in Men with Non-Obstructive Azoospermia

Background

The purpose of the current study was evaluation of the utility of seminal plasma (SP) resistin and leptin in predicting successful surgical sperm retrieval (SSR) in men with non-obstructive azoospermia (NOA).

Methods

This prospective comparative study was conducted in the andrology clinic of a specialized fertility center. In total, 53 NOA men as candidates for either first time micro-testicular sperm extraction (micro-TESE) or repeat micro-TESE and 28 normozoospermic controls were included. ELISA was used for measurement of SP resistin and leptin levels in all participants. Significance level was defined as p<0.05.

Results

The current study demonstrated a significant positive correlation between estradiol (E2) level in serum and SP resistin (r=0.342, p=0.025). Also, there was a highly significant positive correlation between SP leptin and SP resistin (r=0.568, p= 0.001). Interestingly, SP leptin was the only variable that demonstrated a significant correlation with eventful micro-TESE outcome in men who underwent micro-TESE for the first time. Finally, ROC curve showed that SP leptin level of 4.05 ng/ml predicted successful SSR in men who underwent micro-TESE for the first time with a sensitivity of 73.3% and a specificity of 75% as 11 out of 27 (41%) cases showed eventful micro-TESE at or above this cut-off level [AUC of 0.747, 95% CI, lower bound of 0.555, and upper bound of 0.939, p=0.030].

Conclusion

SP leptin can be used as a non-invasive biomarker to predict successful SSR in NOA cases undergoing first time micro-TESE, while SP resistin failed to play the same role.

Effects of Leptin antagonist treatments on testosterone and testis histological characteristics of immature male mice

The present study aimed to ascertain how leptin antagonist injection affected testis weights, testis morphology and testosterone levels in immature male Swiss mice. Animals were administered with anti-leptin antibody subcutaneously, with or without equine chorionic gonadotropin (eCG). Control animals were treated with non-immune serum. Blood and testis were collected. The Androgen profile was analyzed in serum and tissue homogenates, and testes were histologically examined. Compared to controls, mice treated with an anti-leptin antibody with or without gonadotropins had a significant (p<0.05) increase in testis weight. Testosterone concentrations in the testis were significantly (p<0.05) higher in mice administered with anti-leptin antibody compared to control, but testosterone concentrations in blood were not affected. The diameter of seminiferous tubules, the diameter of the lumen and the width of spermatogenic cells were significantly (p<0.05) higher in mice in treatment groups compared to controls. We conclude that anti-leptin antibody administration in immature male mice increased testosterone concentrations in the testis and improved testis histological characteristics. Keywords: leptin; mouse; histology; testis; testosterone; immature male

The major urinary protein gene cluster knockout mouse as a novel model for translational metabolism research

Scientific evidence suggests that not only murine scent communication is regulated by major urinary proteins, but that their expression may also vary in response to metabolism via a yet unknown mechanism. Major urinary proteins are expressed mainly in the liver, showing a sexually dimorphic pattern with substantially higher expression in males. Here, we investigate the metabolic implications of a major urinary protein knockout in twelve-week-old male and female C57BL/6N mice during ad libitum feeding. Despite both sexes of major urinary protein knockout mice displayed numerically increased body weight and visceral adipose tissue proportions compared to sex-matched wildtype mice, the main genotype-specific metabolic differences were observed exclusively in males. Male major urinary protein knockout mice exhibited plasma and hepatic lipid accumulation accompanied by a hepatic transcriptome indicating an activation of lipogenesis. These findings match the higher major urinary protein expression in male compared to female wildtype mice, suggesting a more distinct reduction in energy requirements in male compared to female major urinary protein knockout mice. The observed sex-specific anabolic phenotype confirms a role of major urinary protein in metabolism and, since major urinary proteins are not expressed in humans, suggests the major urinary protein knockout mouse as a potential alternative model for translational metabolism research which needs to be further elucidated.

Prenatal exposure to parabens in association with cord serum adipokine levels and offspring size at birth

BACKGROUND

Paraben exposure is linked to the release of adipokine such as leptin and adiponectin, and both paraben and adipokine may affect fetal growth. The present study aimed to explore the associations among maternal paraben exposure, adipokine level and offspring size.

METHODS

942 mother-newborn pairs from the Sheyang Mini Birth Cohort Study (SMBCS) were enrolled. Data of birth weight, length, head circumference and ponderal index (PI) were obtained from medical records. Maternal urinary parabens were determined by gas chromatography tandem mass spectrometry. Cord serum leptin and adiponectin were measured using ELISA assay. Generalized linear regression was applied to explore the associations among parabens, adipokines and offspring size.

RESULTS

The median levels of leptin and adiponectin were 13.13 μg/L and 161.82 μg/mL. Benzylparaben level was positively associated with leptin (regression coefficient (β) = 0.06, 95% confidence interval (CI): 0.03-0.09; p < 0.01). Leptin level was positively associated with neonatal weight (β = 84.11, 95% CI: 63.22-105.01; p < 0.01), length (β = 0.25, 95% CI: 0.14-0.37; p < 0.01), head circumference (β = 0.15, 95% CI: 0.07-0.22; p < 0.01) and PI (β = 0.23, 95% CI: 0.08-0.39; p < 0.01). Adiponectin was positively associated with neonatal weight (β = 75.94, 95% CI: 29.65-122.23; p < 0.01) and PI (β = 0.43, 95% CI: 0.09-0.77; p = 0.01). Urinary propylparaben concentration (β = -0.10, 95% CI: -0.17 to -0.02; p = 0.01) was negatively associated with head circumference. Sex-stratified analyses indicated the negative association of propylparaben and head circumference was only remained in male neonates.

CONCLUSIONS

Prenatal paraben exposure might affect cord serum leptin levels. Both paraben and adipokine levels may affect fetal growth, and sex-specific differences may exist.

Associations of Obesity with Linear Growth and Puberty

BACKGROUND

The prevalence of obesity in childhood has increased dramatically in recent decades with increased risk of developing cardiometabolic and other comorbidities. Childhood adiposity may also influence processes of growth and puberty.

SUMMARY

Growth patterns of obesity during childhood have been shown to be associated with increased linear growth in early childhood, leading to accelerated epiphyseal growth plate (EGP) maturation. Several hormones secreted by the adipose tissue may affect linear growth in the context of obesity, both via the growth hormone IGF-1 axis and via a direct effect on the EGP. The observation that children with obesity tend to mature earlier than lean children has led to the assumption that the degree of body fatness may trigger the neuroendocrine events that lead to pubertal onset. The most probable link between obesity and puberty is leptin and its interaction with the kisspeptin system, which is an important regulator of puberty. However, peripheral action of adipose tissue could also be involved in changes in the onset of puberty. In addition, nutritional factors, epigenetics, and endocrine-disrupting chemicals are potential mediators linking pubertal onset to obesity. In this review, we focused on interactions of obesity with linear growth and pubertal processes, based on basic research and clinical data in humans.

KEY MESSAGE

Children with obesity are subject to accelerated linear growth with risk of impaired adult height and early puberty, with its psychological consequences. The data highlight another important objective in combatting childhood obesity, for the prevention of abnormal growth and pubertal patterns.

Prenatal exposure to multiple organochlorine compounds and childhood body mass index

Background

Prenatal exposure to organochlorine compounds (OCs) has been associated with increased childhood body mass index (BMI); however, only a few studies have focused on longitudinal BMI trajectories, and none of them used multiple exposure mixture approaches.

Aim

To determine the association between in-utero exposure to eight OCs and childhood BMI measures (BMI and BMI z-score) at 4 years and their yearly change across 4-12 years of age in 279 Rhea child-mother dyads.

Methods

We applied three approaches: (1) linear mixed-effect regressions (LMR) to associate individual compounds with BMI measures; (2) Bayesian weighted quantile sum regressions (BWQSR) to provide an overall OC mixture association with BMI measures; and (3)Bayesian varying coefficient kernel machine regressions (BVCKMR) to model nonlinear and nonadditive associations.

Results

In the LMR, yearly change of BMI measures was consistently associated with a quartile increase in hexachlorobenzene (HCB) (estimate [95% Confidence or Credible interval] BMI: 0.10 [0.06, 0.14]; BMI z-score: 0.02 [0.01, 0.04]). BWQSR results showed that a quartile increase in mixture concentrations was associated with yearly increase of BMI measures (BMI: 0.10 [0.01, 0.18]; BMI z-score: 0.03 [0.003, 0.06]). In the BVCKMR, a quartile increase in dichlorodiphenyldichloroethylene concentrations was associated with higher BMI measures at 4 years (BMI: 0.33 [0.24, 0.43]; BMI z-score: 0.19 [0.15, 0.24]); whereas a quartile increase in HCB and polychlorinated biphenyls (PCB)-118 levels was positively associated with BMI measures yearly change (BMI: HCB:0.10 [0.07, 0.13], PCB-118:0.08 [0.04, 012]; BMI z-score: HCB:0.03 [0.02, 0.05], PCB-118:0.02 [0.002,04]). BVCKMR suggested that PCBs had nonlinear relationships with BMI measures, and HCB interacted with other compounds.

Conclusions

All analyses consistently demonstrated detrimental associations between prenatal OC exposures and childhood BMI measures.

Longitudinal study of body mass index and percentage of overweight in Japanese children grouped by maturity

Childhood obesity is a known risk factor for adult diseases, making its evaluation highly important. However, the evaluation is complex because there is no gold standard method. Body mass index (BMI) and percentage of overweight (POW) are widely used in Japan. However, they have the following limitations: it is difficult to set cutoffs for BMI because it dynamically varies in childhood, and POW has not been studied extensively, especially regarding its difference during maturity. Therefore, our study analyzed BMI/POW in Japanese children grouped by maturity. We used longitudinal school check-up data collected from elementary and junior high schools in 20 municipalities. We made percentile curves of BMI/POW and calculated the percentage of participants considered overweight/obese by sex, age, and maturity. Maximum increment age (MIA) was calculated using the graphical fitting method. We included 35,461 subjects aged 15 in 2018. Early-maturing children had higher BMI. The difference among maturity groups decreased by shifting the percentile curves by differences in MIA. Therefore, the use of BMI might lead to the overestimation of overweight/obesity in early-maturing children and underestimation in late-maturing children. The POW percentile curves were "N"-shaped around the MIA, indicating the inappropriate evaluation during this period. The percentile curves of children categorized as overweight/obese were also "N"-shaped, confirming that MIA affects the evaluation of childhood obesity. The possibility of overestimation/underestimation needs verification with the data of accurate age, pubertal changes, and adult diseases. In conclusion, it is difficult to evaluate childhood obesity only with height and weight.

Hypothalamic mechanisms of obesity-associated disturbance of hypothalamic-pituitary-ovarian axis

Ovulatory disorders are the most common clinical feature exhibited among obese women. Initiation of ovulation physiologically requires a surge of gonadotropin-releasing hormone (GnRH) released from GnRH neurons located in the hypothalamus. These GnRH neurons receive metabolic signals from circulation and vicinal neurons to regulate GnRH release. Leptin acts indirectly on GnRH via adjacent leptin receptor (LEPR)-expressing neurons such as proopiomelanocortin (POMC), neuropeptide Y (NPY)/agouti-related peptide (AgRP), and neuronal nitric oxide (NO) synthase (nNOS) neurons to affect GnRH neuronal activities. Additionally, hypothalamic inflammation also affects ovulation independent of obesity. Therefore, this review focuses on hypothalamic mechanisms that underlie the disturbance of hypothalamic-pituitary-ovarian (HPO) axis during obesity with an attempt to promote future studies and/or novel therapeutic strategies for ovulatory disorders in obesity.

Peripheral versus central insulin and leptin resistance: Role in metabolic disorders, cognition, and neuropsychiatric diseases

Insulin and leptin are classically regarded as peptide hormones that play key roles in metabolism. In actuality, they serve several functions in both the periphery and central nervous system (CNS). Likewise, insulin and leptin resistance can occur both peripherally and centrally. Metabolic disorders such as diabetes and obesity share several key features including insulin and leptin resistance. While the peripheral effects of these disorders are well-known (i.e. cardiovascular disease, hypertension, stroke, dyslipidemia, etc.), the CNS complications of leptin and insulin resistance have come into sharper focus. Both preclinical and clinical findings have indicated that insulin and leptin resistance are associated with cognitive deficits and neuropsychiatric diseases such as depression. Importantly, these studies also suggest that these deficits in neuroplasticity can be reversed by restoration of insulin and leptin sensitivity. In view of these observations, this review will describe, in detail, the peripheral and central functions of insulin and leptin and explain the role of insulin and leptin resistance in various metabolic disorders, cognition, and neuropsychiatric diseases.

Invited Commentary: Childhood Adiposity and the Onset of Puberty-It Turns Out There Is More to Be Learned

The literature on the relationship between adiposity and the onset of puberty is extensive, both in size and in the length of time this question has been alive in the biomedical literature. It is easy to wonder, then, whether there is anything new to be learned in this crowded field. In this issue of the Journal, Deardorff et al. (Am J Epidemiol. 2022;191(1):7-16) show that it is still possible to innovate in this area. The authors report on the relationship between body mass index at age 5 years and a variety of markers of the onset of puberty. Consistent with the current literature, they show no association between body mass index at age 5 and pubertal onset in boys. They also show an association between obesity at age 5 with earlier onset of secondary sexual characteristics in girls, making an important subject-matter contribution that addresses many of the concerns of the existing literature in assigning causality. At the same time, the authors make an important, although less evident contribution to the practice of epidemiology for studies where the assessment of pubertal status is of interest.

The relation between obesity, kisspeptin, leptin, and male fertility

Over the past decades, obesity and infertility in men increased in parallel, and the association between both phenomena have been examined by several researchers. despite the fact that there is no agreement, obesity appears to affect the reproductive potential of men through various mechanisms, such as changes in the hypothalamic-pituitary-testicular (HPT) axis, spermatogenesis, sperm quality and/or alteration of sexual health. Leptin is a hormone produced by the adipose tissue, and its production elevates with increasing body fat. Many studies have supported the relationship between raised leptin production and reproductive function regulation. In fact, Leptin acts on the HPT axis in men at all levels. However, most obese men are insensitive to increased production of endogenous leptin and functional leptin resistance development. Recently, it has been recommended that Kisspeptin neurons mediate the leptin's effects on the reproductive system. Kisspeptin binding to its receptor on gonadotropin-releasing hormone (GnRH) neurons, activates the mammal's reproductive axis and stimulates GnRH release. Increasing infertility associated with obesity is probably mediated by the Kisspeptin-GnRH pathway. In this review, the link between obesity, kisspeptin, leptin, and male fertility will be discussed.

Leptin Is an Important Endocrine Player That Directly Activates Gonadotropic Cells in Teleost Fish, Chub Mackerel

Leptin, secreted by adipocytes, directly influences the onset of puberty in mammals. Our previous study showed that leptin stimulation could promote the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from pituitary cells in primary culture and ovarian development in chub mackerel. This study aimed to elucidate the detailed mechanism of leptin-induced effects on gonadotropin hormone-producing cells. We produced recombinant leptin using silkworm pupae and investigated the effects of leptin on FSH and LH secretion and gene expression in the primary culture of pituitary cells from chub mackerel. The presence or absence of co-expression of lepr mRNA, FSH and LH b-subunit mRNA in gonadotropic cells was examined by double-labeled in situ hybridization. The addition of leptin significantly increased the secretion and gene expression of FSH and LH from male and female pituitary cells in primary culture. In contrast, gonadotropin-releasing hormone 1 affected neither FSH secretion in cells from females nor fshb and lhb expression in cells from males and females. The expression of lepr was observed in FSH- and LH-producing cells of both males and females. The results indicate that leptin directly regulates gonadotropin synthesis and secretion and plays an important role in the induction of puberty in teleost fish.

A potential role for the adrenal gland in autism

Androgens have been implicated in autism pathophysiology as recently, prenatal exposure to elevated androgens has been proposed as risk factor. However, published data on postnatal sex hormone levels in autistic children are controversial and the source of prenatal androgen exposure in autism remains unknown. Therefore, this study investigated postnatal sex hormone levels and dehydroepiandrosterone (DHEA) to shed light on a potential role for the adrenal gland in autism pathophysiology. A case-control study investigating estradiol (E2), DHEA, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels was conducted with 31 Saudi males with autism and 28 healthy, age-matched boys plasma. Moreover, correlation analysis with measured hormones and previously measured total testosterone (TT) and free testosterone (FT) in the same group of autism was conducted. DHEA was significantly higher (p < 0.05) in the autism group compared to controls. DHEA positively correlated with previously measured TT (r = + 0.79, p < 0.001) and FT (r = + 0.72, p < 0.001) levels in the same autism group. FSH levels were also significantly higher in the autism group than in the control group (p < 0.01). To the best of our knowledge, this is the first study to report a strong positive correlation between TT, FT and DHEA, suggesting an adrenal source for elevated androgen levels.

Trajectory of leptin and leptin receptor in vertebrates: Structure, function and their regulation

The present review provides a comparative insight into structure, function and control of leptin system in fishes, herptiles, birds and mammals. In general, leptin acts as an anorexigenic hormone since its administration results in decrease of food intake in vertebrates. Nonetheless, functional paradox arises in fishes from contradictory observations on level of leptin during fasting and re-feeding. In addition, leptin is shown to modulate metabolic functions in fishes, reptiles, birds and mammals. Leptin also regulates reproductive and immune functions though more studies are warranted in non-mammalian vertebrates. The expression of leptin and its receptor is influenced by numerous factors including sex steroids, stress and stress-induced catecholamines and glucocorticoids though their effect in non-mammalian vertebrates is hard to be generalized due to limited studies.

The influence of intermittent hypoxia, obesity, and diabetes on male genitourinary anatomy and voiding physiology

We used male BTBR mice carrying the Lep^ob mutation, which are subject to severe and progressive obesity and diabetes beginning at 6 wk of age, to examine the influence of one specific manifestation of sleep apnea, intermittent hypoxia (IH), on male urinary voiding physiology and genitourinary anatomy. A custom device was used to deliver continuous normoxia (control) or IH to wild-type and Lep^ob/ob (mutant) mice for 2 wk. IH was delivered during the 12-h inactive (light) period in the form of 90 s of 6% O₂ followed by 90 s of room air. Continuous room air was delivered during the 12-h active (dark) period. We then evaluated genitourinary anatomy and physiology. As expected for the type 2 diabetes phenotype, mutant mice consumed more food and water, weighed more, and voided more frequently and in larger urine volumes. They also had larger bladder volumes but smaller prostates, seminal vesicles, and urethras than wild-type mice. IH decreased food consumption and increased bladder relative weight independent of genotype and increased urine glucose concentration in mutant mice. When evaluated based on genotype (normoxia + IH), the incidence of pathogenic bacteriuria was greater in mutant mice than in wild-type mice, and among mice exposed to IH, bacteriuria incidence was greater in mutant mice than in wild-type mice. We conclude that IH exposure and type 2 diabetes can act independently and together to modify male mouse urinary function. NEW & NOTEWORTHY Metabolic syndrome and obstructive sleep apnea are common in aging men, and both have been linked to urinary voiding dysfunction. Here, we show that metabolic syndrome and intermittent hypoxia (a manifestation of sleep apnea) have individual and combined influences on voiding function and urogenital anatomy in male mice.

The Importance of Leptin to Reproduction

A healthy nutritional state is required for all aspects of reproduction and is signaled by the adipokine leptin. Leptin acts in a relatively narrow concentration range: too much or too little will compromise fertility. The leptin signal timing is important to prepubertal development in both sexes. In the brain, leptin acts on ventral premammillary neurons which signal kisspeptin (Kiss1) neurons to stimulate gonadotropin releasing hormone (GnRH) neurons. Suppression of Kiss1 neurons occurs when agouti-related peptide neurons are activated by reduced leptin, because leptin normally suppresses these orexigenic neurons. In the pituitary, leptin stimulates production of GnRH receptors (GnRHRs) and follicle-stimulating hormone at midcycle, by activating pathways that derepress actions of the messenger ribonucleic acid translational regulatory protein Musashi. In females, rising estrogen stimulates a rise in serum leptin, which peaks at midcycle, synchronizing with nocturnal luteinizing hormone pulses. The normal range of serum leptin levels (10-20 ng/mL) along with gonadotropins and growth factors promote ovarian granulosa and theca cell functions and oocyte maturation. In males, the prepubertal rise in leptin promotes testicular development. However, a decline in leptin levels in prepubertal boys reflects inhibition of leptin secretion by rising androgens. In adult males, leptin levels are 10% to 50% of those in females, and high leptin inhibits testicular function. The obesity epidemic has elucidated leptin resistance pathways, with too much leptin in either sex leading to infertility. Under conditions of balanced nutrition, however, the secretion of leptin is timed and regulated within a narrow level range that optimizes its trophic effects.

[Role of leptin and nuclear receptor PPARγ in PCOS pathogenesis]

Polycystic ovary syndrome (PCOS) is the most common cause of female endocrine infertility. Insulin resistanсе is supposed to be one of the essential factors of this disease pathways. At the same time, the mechanisms of PCOS development in insulin-resistant patients have not been completely established. Leptin and Peroxisome Proliferator-Activated Receptor γ(PPARγ) are involved in carbohydrate metabolism and reproduction function regulation. It indicates that leptin and PPARγ possibly play a role in the pathways of PCOS. This article is a review of publications on this issue. The purpose of this review was to systematize the available information on the molecular mechanisms that determine the role of leptin and PPARγ in the development of PCOS. The literature search was carried out from 04/05/2020 to 05/17/2020 using the scientific literature databases: NCBI PubMed (foreign sources) and Cyberleninka (domestic sources). We analyzed publications for the period 1990-2020.The review presents the current understanding of the possible role of leptin and PPARγ in the regulation of endocrine, immune systems, and reproductive function, as well as in the development of PCOS. Currently, no studies cover the mechanisms of interaction between leptin and PPARγ in the pathways of this syndrome. The available studies indicating the individual contribution and association of leptin and PPARγ with PCOS are conflicting and have many limitations. Therefore, more studies of direct and indirect interaction of leptin and PPARγ, as well as their role in PCOS pathways, are needed.

Nutrient regulation of somatic growth in teleost fish. The interaction between somatic growth, feeding and metabolism

This review covers the current knowledge on the regulation of the somatic growth axis and its interaction with metabolism and feeding regulation. The main endocrine and neuroendocrine factors regulating both the growth axis and feeding behavior will be briefly summarized. Recently discovered neuropeptides and peptide hormones will be mentioned in relation to feeding control as well as growth hormone regulation. In addition, the influence of nutrient and nutrient sensing mechanisms on growth axis will be highlighted. We expect that in this process gaps of knowledge will be exposed, stimulating future research in those areas.

Estradiol and the feeding state modulate the interaction between leptin and the nitrergic system in female rats

Leptin mediates the interaction between reproductive function and energy balance. However, leptin receptors are not expressed in neurons that produce gonadotropin-releasing hormone (GnRH), likely indicating an indirect action through interneurons. Among likely neurons that modulate the secretion of GnRH are NO (nitric oxide) neurons. We assessed whether estradiol and feeding conditions modulate a possible interaction between leptin and NO in brain areas related to the control of reproductive function. Estradiol-treated and untreated ovariectomized rats were normally fed or fasted for 48 h. Then, saline (control) or leptin (3 μg/1 μl) intracerebroventricular microinjections were administered, and after thirty minutes, the brains collected subsequent to the decapitation or transcardially perfusion. Leptin and estradiol increased NO synthase (nNOS) gene expression (RT-PCR) and content (Western blotting) in the medial preoptic area (MPOA) and medial basal hypothalamus (MBH) only in fasted rats. Leptin increased: 1-phosphorylated-signal transducer and activator of transcription-3(pSTAT3) (immunohistochemistry) in the MPOA and various hypothalamic nuclei [arcuate (ARC); ventromedial (VMH); dorsal/ventral dorsomedial (dDMH/vDMH); premammilar ventral (PMV)], effects potentiated by estradiol/fasting interaction; 2- nNOS/pSTAT3 coexpression in the MPOA only in estradiol-treated, fasted rats; 3- nNOS-immunoreactive cell expression in the VMH, DMH and PMV (areas related to reproductive function control) of estradiol -treated rats. Thus, when leptin is reduced during fasting, leptin replacement effectively increased the expression of nitric oxide, which activated the HPG axis only in the presence of estradiol. Estradiol modulates the nitrergic system, leptin sensitivity and consequently leptin's effects on the nitrergic system in hypothalamus and in particular vDMH and PMV.

Association between obesity-associated markers and semen quality parameters and serum reproductive hormones in Chinese infertile men

BACKGROUND

The current evidence on the association between obesity-associated markers and semen quality, serum reproductive hormones and lipids remains inconsistent. In this study, we tested the hypothesis that, in infertile Chinese men, body mass index (BMI) negatively correlates with sperm concentration, serum total testosterone (TT), and high-density lipoprotein cholesterol (HDL-C). The relationship between other obesity-associated markers and semen quality parameters, serum reproductive hormones, lipids and leptin were also investigated.

METHODS

181 Chinese infertile men were recruited from September 2018 to September 2019. Their obesity-associated markers, semen parameters, and serum reproductive hormones, lipids and leptin were detected. Statistical analysis was performed to assess the relationship between obesity-associated markers and semen quality, serum reproductive hormones, lipids and leptin.

RESULT(S)

Statistically negative correlation was found between other obesity-associated markers (e.g. waist-to-hip ratio and waist-to-height ratio) and semen parameters (e.g. sperm concentration, ratio of progressive motility and ratio of non-progressive motility), while no significant correlation was found between BMI and semen quality, serum reproductive hormones, lipids and leptin. Ratio of morphologically normal sperm was negatively correlated with serum lipids including total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), leptin and seminal superoxide dismutase. Ratio of progressive sperm, sperm concentration and ratio of morphologically normal sperm exhibited significantly lower values in overweight group than normal group. Estradiol (E2) and E2/TT were significantly higher in obese group than normal group, while TT level was significantly lower in obese group than normal group. Univariate and multivariate analysis indicated that TC was significantly associated with BMI. Serum leptin concentration was positively correlated with seminal leptin concentration in overweight and obese groups.

CONCLUSION(S)

No significant correlation was found between BMI and sperm concentration, serum TT and HDL-C, while other obesity-associated markers were found to negatively correlate with sperm concentration, ratio of progressive motility and ratio of non-progressive motility. Statistically significant correlations between serum reproductive hormones, lipids and leptin also existed in Chinese infertile men.

The Impact of Photoperiod on the Leptin Sensitivity and Course of Inflammation in the Anterior Pituitary

Leptin has a modulatory impact on the course of inflammation, affecting the expression of proinflammatory cytokines and their receptors. Pathophysiological leptin resistance identified in humans occurs typically in sheep during the long-day photoperiod. This study aimed to determine the effect of the photoperiod with relation to the leptin-modulating action on the expression of the proinflammatory cytokines and their receptors in the anterior pituitary under physiological or acute inflammation. Two in vivo experiments were conducted on 24 blackface sheep per experiment in different photoperiods. The real-time PCR analysis for the expression of the genes IL1B, IL1R1, IL1R2, IL6, IL6R, IL6ST, TNF, TNFR1, and TNFR2 was performed. Expression of all examined genes, except IL1β and IL1R2, was higher during short days. The leptin injection increased the expression of all examined genes during short days. In short days the synergistic effect of lipopolysaccharide and leptin increased the expression of IL1B, IL1R1, IL1R2, IL6, TNF, and TNFR2, and decreased expression of IL6ST. This mechanism was inhibited during long days for the expression of IL1R1, IL6, IL6ST, and TNFR1. The obtained results suggest the occurrence of leptin resistance during long days and suggest that leptin modulates the course of inflammation in a photoperiod-dependent manner in the anterior pituitary.

Cx30.2 deletion causes imbalances in testicular Cx43, Cx46, and Cx50 and insulin receptors. Reciprocally, diabetes/obesity alters Cx30.2 in mouse testis

Cx30.2 protein content and localization were assessed during development. An account of Cx30.2, Cx43, Cx46, and Cx50, and insulin receptor (IR) responses to Cx30.2, Cx46, or Cx50 deficiency in mouse interstitial tissue (ITf)- and seminiferous tubule-enriched fractions (STf) is given. The impact of high glucose/insulin on Cx30.2 was investigated in spontaneously diabetic and obese db/db and ob/ob mouse testis and anterior pituitary (AP). Cx30.2 labeled contacts in vascular endothelial and Leydig cells and Sertoli cell junctions in stage V-VII. Cx30.2 expression is regulated differently in the interstitium and tubules. Cx30.2 at 30-kDa levels peaked by 28 days in ITf and by 14 days in STf. In STf, deleting Cx30.2 decreased Cx43 and Cx50, whereas deleting Cx50 downregulated Cx30.2. The opposite occurred in ITf. In STf, deleting Cx30.2 upregulated Cx46 except the full-length reciprocally, deleting Cx46 upregulated Cx30.2. In ITf, Cx30.2 deficiency upregulated full-length and phosphorylated Cx46, whereas deleting Cx46 downregulated 48- to 50-kDa Cx30.2. The db/db and ob/ob mouse ITf, STf, and AP showed imbalanced Cx30.2 levels. IRα levels at 135 kDa declined in Cx30.2-/- and Cx50-/- mouse ITf and Cx46-/- and Cx50-/- STf. IRβ at 98 to 110 kDa dropped in Cx30.2-/- and Cx46-/- mice STf suggesting that Cx30.2 deficiency decreases active IR sites. The results show the connexins interdependence and interaction and that altering a single connexin changes the remaining connexins expression, which can modify gap junction-mediated glucose exchanges in contacting cells. Data suggest that glucose/insulin influences Cx30.2 turnover in testis and AP and, reciprocally, that connexins modulate testis glucose uptake and response to insulin.

Metabolic control of teleost reproduction by leptin and its complements: Understanding current insights from mammals

Reproduction is expensive. Hence, reproductive physiology is sensitive to an array of endogenous signals that provide information on metabolic and nutritional sufficiency. Although metabolic gating of reproductive function in mammals, as evidenced by studies demonstrating delayed puberty and perturbed fertility, has long been understood to be a function of energy sufficiency, an understanding of the endocrine regulators of this relationship have emerged only within recent decades. Peripheral signals including leptin and cortisol have long been implicated in the physiological integration of metabolism and reproduction. Recent studies have begun to explore possible roles for these two hormones in the regulation of reproduction in teleost fishes, as well as a role for leptin as a catabolic stress hormone. In this review, we briefly explore the reproductive actions of leptin and cortisol in mammals and teleost fishes and possible role of both hormones as putative modulators of the reproductive axis during stress events.

Low Testosterone in Male Cancer Patients and Survivors

INTRODUCTION

Hypogonadism (HG) is prevalent among patients with ongoing advanced cancer and cancer survivors. The etiology of HG in these patients is multifactorial and can be examined from cancer-related and cancer-treatment perspectives. There is evidence that HG contributes to increased morbidity in male cancer patients. Testosterone replacement therapy (TRT) for cancer survivors and advanced cancer patients is not well studied outside of prostate cancer. Here, we evaluate and summarize the current literature on HG in male cancer patients, including the role of TRT in nonprostate cancer patients.

OBJECTIVE

To summarize and present the literature for the background, etiology, clinical consequences, and treatment for HG in male cancer patients and survivors.

METHODS

A literature review was performed in MEDLINE between 1980 and 2020 using the terms hypogonadism, advanced cancer, testosterone replacement therapy, quality of life, and cancer survivors. Studies including only prostate cancer patients were excluded.

RESULTS

The main outcome measure was to complete a review of peer-reviewed literature. HG is not only prevalent among male cancer patients and survivors but also clinically reduces quality of life and increases morbidity. The etiology of HG in male cancer patients and survivors is multifactorial. There are few studies examining the benefit of TRT in these patient populations. The results of randomized controlled trials show potential benefit for TRT in hypogonadal male cancer survivors and those with advanced cancer.

CONCLUSION

HG affects many male cancer patients and survivors because of a multifactorial etiology. HG in these patients contributes to increased morbidity and reduced quality of life. Treatment of HG in male cancer patients is not well studied, and further studies are needed to elucidate the role of TRT. Xu P, Choi E, White K, et al. Low Testosterone in Male Cancer Patients and Survivors. Sex Med 2021;9:133-142.

Glucose, insulin, insulin receptor subunits α and β in normal and spontaneously diabetic and obese ob/ob and db/db infertile mouse testis and hypophysis

BACKGROUND

Type 2 diabetes touches young subjects of reproductive age in epidemic proportion. This study assesses glucose, total InsulinT, Insulin2 and insulin receptor subunits α and β in testis during mouse development then, in the spontaneously type 2 diabetes models associated with infertility db/db and ob/ob mice. IR-β and α were also assessed in spermatozoa (SPZ), anterior pituitary (AP) and serum.

METHODS

Serum and tissue glucose were measured with enzymatic colorimetric assays and InsulinT and Insulin2 by ELISAs in serum, interstitial tissue- (ITf) and seminiferous tubule (STf) fractions in14- > 60-day-old normal and db/db, ob/ob and wild type (WT) mice. IR subunits were assessed by immunoblotting in tissues and by immunoprecipitation followed by immunoblotting in serum.

RESULTS

Development: Glucose increased in serum, ITf and STf. InsulinT and Insulin2 dropped in serum; both were higher in STf than in ITf. In > 60-day-old mouse ITf, insulinT rose whereas Insulin2 decreased; InsulinT and Insulin2 rose concurrently in STf. Glucose and insulin were high in > 60-day-old ITf; in STf high insulin2 accompanied low glucose. One hundred ten kDa IR-β peaked in 28-day-old ITf and 14-day-old STf. One hundred thirty five kDa IR-α was high in ITf but decreased in STf. Glucose escalated in db/db and ob/ob sera. Glucose doubled in ITf while being halved in STf in db/db mice. Glucose significantly dropped in db/db and ob/ob mice spermatozoa. InsulinT and Insulin2 rose significantly in the serum, ITf and STf in db/db and ob/ob mice. One hundred ten kDa IR-β and 135 kDa IR-α decreased in db/db and ob/ob ITf. Only 110 kDa IR-β dropped in db/db and ob/ob STf and AP. One hundred ten kDa IR-β fell in db/db and ob/ob SPZ. One hundred ten kDa sIR-α rose in the db/db and ob/ob mouse sera.

CONCLUSION

Insulin regulates glucose in tubules not in the interstitium. The mouse interstitium contains InsulinT and Insulin2 whereas tubules contain Insulin2. Decreased 110 kDa IR-β and 135 kDa IR-α in the db/db and ob/ob interstitial tissue suggest a loss of active receptor sites that could alter the testicular cell insulin binding and response to the hormone. Decreased IR-β levels were insufficient to stimulate downstream effectors in AP and tubules. IR-α shedding increased in db/db and ob/ob mice.

A case of generalized lipodystrophy-associated progeroid syndrome treated by leptin replacement with short and long-term monitoring of the metabolic and endocrine profiles

We herein report a case of a 28-year-old man with generalized lipodystrophy-associated progeroid syndrome treated by leptin replacement. He showed symptoms of generalized lipodystrophy around onset of puberty. His body mass index was 11.9 kg/m², and he had a short stature, birdlike facies, dental crowding due to micrognathia, partial graying and loss of hair, and a high-pitched voice, all of which are typical features of the progeroid syndrome. Laboratory examinations and abdominal ultrasonography revealed diabetes mellitus, insulin-resistance, dyslipidemia, decreased serum leptin levels (2.2 ng/mL), elevated serum hepatobiliary enzyme levels and fatty liver. Whole exome sequencing revealed de novo heterozygous LMNA p.T10I mutation, indicating generalized lipodystrophy-associated progeroid syndrome, which is a newly identified subtype of atypical progeroid syndrome characterized by severe metabolic abnormalities. Daily injection of metreleptin [1.2 mg (0.04 mg/kg)/day] was started. Metreleptin treatment significantly improved his diabetes from HbA1c 11.0% to 5.4% in six months. It also elevated serum testosterone levels. Elevated serum testosterone levels persisted even 1 year after the initiation of metreleptin treatment. To the best of our knowledge, this is the first Japanese case report of generalized lipodystrophy-associated progeroid syndrome. Furthermore, we evaluated short and long-term effectiveness of leptin replacement on generalized lipodystrophy by monitoring metabolic and endocrine profiles.

Model for Studying the Effects of Chronic Metabolic Disease on Endogenous Bone Marrow Stem Cell Populations

Disease-associated impairment/dysfunction of stem cell populations is prominent in chronic metabolic and inflammatory diseases, such as type 2 diabetes mellitus (DM) where the multifunctional properties (viability, proliferation, paracrine secretion, multilineage differentiation) of bone marrow resident mesenchymal stem cells (MSCs) can be affected. The growth and viability impairments make it difficult to study the underlying molecular mechanisms related to the dysfunction of these cells in vitro. We have consequently optimized the isolation and culture conditions for impaired/dysfunctional bone marrow MSCs from B6.Cg-Lep^ob/J obese prediabetic mice. The method described here permits ex vivo investigations into disease-associated functional impairments and the dysregulated molecular mechanisms in these primary MSCs through direct comparisons with their healthy wild-type C57BL6/J control mouse counterparts.

Leptin actions through the nitrergic system to modulate the hypothalamic expression of the kiss1 mRNA in the female rat

Gonadotrophin-releasing hormone (GnRH) is the main controller of the reproductive axis and stimulates the synthesis and secretion of gonadotrophins. Estrogen is the main peripheral factor controlling GnRH secretion, and this action is mainly mediated by the transsynaptic pathway through nitric oxide, kisspeptin, leptin, among other factors. Kisspeptin is the most potent factor known to induce GnRH release. Nitric oxide and leptin also promote GnRH release; however, neurons expressing GnRH do not express the leptin receptor (OB-R). Leptin seems to modulate the expression of genes and proteins involved in the kisspeptin system. However, few kisspeptin-synthesizing cells in the arcuate nucleus (ARC) and few cells, if any, in the preoptic area (POA) express OB-R; this indicates an indirect mechanism of leptin action on kisspeptin. Nitric oxide is an important intermediate in the actions of leptin in the central nervous system. Thus, this work aimed to verify the numbers of nNOS cells were activated by leptin in different hypothalamic areas; the modulatory effects of the nitrergic system on the kisspeptin system; and the indirect regulatory effect of leptin on the kisspeptin system via nitric oxide. Ovariectomized rats were treated with estrogen or a vehicle and received an intracerebroventricular (i.c.v.) injection of a nitric oxide donor, leptin or neuronal nitric oxide synthase (nNOS) enzyme inhibitor. Thirty minutes after the injection, the animals were decapitated. Leptin acts directly on nitrergic neurons in different hypothalamic regions, and the effects on the ventral premammillary nucleus (PMV) and ventral dorsomedial hypothalamus (vDMH) are enhanced. The use of a nitric oxide donor or the administration of leptin stimulates the expression of the kisspeptin mRNA in the ARC of animals with or without estrogenic action; however, these changes are not observed in the POA. In addition, the action of leptin on the expression of the kisspeptin mRNA in the ARC is blocked by a nitric oxide synthesis inhibitor. We concluded that the effects of leptin on the central nervous system are at least partially mediated by the nitrergic system. Also, nitric oxide acts on the kisspeptin system by modulating the expression of the kisspeptin mRNA, and leptin at least partially modulates the kisspeptin system through the nitrergic system, particularly in the ARC.

Maternal high-fat diet triggers metabolic syndrome disorders that are transferred to first and second offspring generations

A high-fat (H) diet increases metabolic disorders in offspring. However, there is great variability in the literature regarding the time of exposure, composition of the H diets offered to the genitors and/or offspring and parameters evaluated. Here, we investigated the effect of a H diet subjected to the genitors on different cardio-metabolic parameters on first (F1)- and second (F2)-generation offspring. Female Fischer rats, during mating, gestation and breast-feeding, were subjected to the H diet (G0HF) or control (G0CF) diets. Part of F1 offspring becomes G1 genitors for generating the F2 offspring. After weaning, F1 and F2 rats consumed only the C diet. Nutritional, biometric, biochemical and haemodynamic parameters were evaluated. G0HF genitors had a reduction in food intake but energy intake was similar to the control group. Compared with the control group, the F1H and F2H offspring presented increased plasma leptin, insulin and fasting glucose levels, dietary intake, energy intake, adiposity index, mean arterial pressure, sympathetic drive evidenced by the hexamethonium and insulin resistance. Our data showed that only during mating, gestation and breast-feeding, maternal H diet induced cardio-metabolic disorders characteristic of human metabolic syndrome that were transferred to both females and males of F1 and F2 offspring, even if they were fed control diet after weaning. This process probably occurs due to the disturbance in mechanisms related to leptin that increases energy intake in F1H and F2H offspring. The present data reinforce the importance of balanced diet during pregnancy and breast-feeding for the health of the F1 and F2 offspring.

Functional Relationship between Leptin and Nitric Oxide in Metabolism

Leptin, the product of the ob gene, was originally described as a satiety factor, playing a crucial role in the control of body weight. Nevertheless, the wide distribution of leptin receptors in peripheral tissues supports that leptin exerts pleiotropic biological effects, consisting of the modulation of numerous processes including thermogenesis, reproduction, angiogenesis, hematopoiesis, osteogenesis, neuroendocrine, and immune functions as well as arterial pressure control. Nitric oxide (NO) is a free radical synthesized from L-arginine by the action of the NO synthase (NOS) enzyme. Three NOS isoforms have been identified: the neuronal NOS (nNOS) and endothelial NOS (eNOS) constitutive isoforms, and the inducible NOS (iNOS). NO mediates multiple biological effects in a variety of physiological systems such as energy balance, blood pressure, reproduction, immune response, or reproduction. Leptin and NO on their own participate in multiple common physiological processes, with a functional relationship between both factors having been identified. The present review describes the functional relationship between leptin and NO in different physiological processes.

Effects of hypothyroidism on the mesenteric and omental adipose tissue in rats

To characterize the influence of hypothyroidism on the endocrine activity of mesenteric and omental adipose tissue (MOAT) and the peripheral regulation of energy balance (EB) in rats, we analyzed food intake (FI); basal metabolic rate (BMR); locomotor activity; body weight (BW); serum hormone concentrations and the expression of their receptors in MOAT. We evaluated the morphology and differentiation of adipocytes. Hypothyroidism decreased FI, BMR and BW. The percentage of visceral white adipose tissue (WAT) depots and the morphology of adipocytes were similar to euthyroid rats. Serum leptin and adiponectin expression in MOAT were altered by hypothyroidism. The expression of Perilipin 1, HSL, UCP1 and PRDM16 was significantly lower in MOAT of hypothyroid animals. Hypothyroidism in rats leads to a compensated EB by inducing a white adipocyte dysfunction and a decrease in BW, BMR, FI and adipokine secretions without changing the percentage of WAT depots and the morphology of the MOAT.

Pubertal abnormalities in adolescents with chronic disease

Pubertal disorders in the context of chronic disease especially in those with chronic inflammatory disorders or those requiring prolonged periods of treatment with glucocorticoid are common reasons for referral to the paediatric endocrine clinic. Disorders of puberty are also common in adolescents with disability requiring management by paediatric endocrinologists. In these adolescents, impaired skeletal development is also observed and this can be associated with fragility fractures. Chronic inflammation, glucocorticoid and sub-optimal nutrition all impact on the hypothalamic-pituitary gonadal axis, and can also impact on skeletal development locally by their effects on the growth plate and bone. Addressing pubertal disorders is important to ensure adolescents with chronic disease are matched with their peers, promote adequate bone mass accrual and linear growth. Careful discussion with primary clinicians, the young person and the family is needed when instituting endocrine therapies to address puberty and manage bone health.

Neuroanatomical Framework of the Metabolic Control of Reproduction

A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.

The effects of leptin on plasma concentrations of prolactin, growth hormone, and melatonin vary depending on the stage of pregnancy in sheep

The effects of hyperleptinemia and leptin resistance during gestation are unclear. Leptin, an important neuroendocrine regulator, has anorexic effects, but its interactions with other metabolic hormones during pregnancy are unclear. We examined potential roles of leptin in regulating prolactin (PRL), GH, and melatonin plasma concentrations during pregnancy in Polish Longwool ewes. Twelve estrus-synchronized ewes carrying twins after mating were randomly assigned to receive i.v. injections of saline or recombinant ovine leptin (2.5 or 5.0 µg/kg BW). Blood samples were collected (15-min intervals over 4 h) immediately before the first injection at dusk and kept under red light. Treatments were repeated at 2-wk intervals, starting before mating and continuing from days 30 to 135 of gestation. Concentrations of plasma PRL, GH, and melatonin were determined using a validated RIA. The effects of leptin on hormone plasma concentrations varied depending on pregnancy stage and leptin dose. PRL plasma concentrations were affected at most stages of pregnancy and before gestation. In non-, very early- (day 30), and late- (day 120 and 135) pregnant ewes, exogenous leptin stimulated PRL (P < 0.001) plasma concentrations, while during the second month of gestation, it decreased PRL concentrations (P < 0.01). Leptin affected GH plasma concentrations (P < 0.05) only during the first 2 mo of pregnancy, with no effects during the second part of gestation or before pregnancy. In early-pregnant ewes (day 30 and 45), leptin decreased melatonin plasma concentrations (P < 0.05), but at day 60, leptin stimulated melatonin plasma concentrations at low (P < 0.01) and high doses (P < 0.05), with no effects in ewes after 105 d of gestation. These data indicate specific pregnancy-induced endocrine adaptations to changes in energy homeostasis, supporting the hypothesis that leptin affects PRL, GH, and melatonin release during gestation.

Insights into leptin signaling and male reproductive health: the missing link between overweight and subfertility?

Obesity stands as one of the greatest healthcare challenges of the 21st century. Obesity in reproductive-age men is ever more frequent and is reaching upsetting levels. At the same time, fertility has taken an inverse direction and is decreasing, leading to an increased demand for fertility treatments. In half of infertile couples, there is a male factor alone or combined with a female factor. Furthermore, male fertility parameters such as sperm count and concentration went on a downward spiral during the last few decades and are now approaching the minimum levels established to achieve successful fertilization. Hence, the hypothesis that obesity and deleterious effects in male reproductive health, as reflected in deterioration of sperm parameters, are somehow related is tempting. Most often, overweight and obese individuals present leptin levels directly proportional to the increased fat mass. Leptin, besides the well-described central hypothalamic effects, also acts in several peripheral organs, including the testes, thus highlighting a possible regulatory role in male reproductive function. In the last years, research focusing on leptin effects in male reproductive function has unveiled additional roles and molecular mechanisms of action for this hormone at the testicular level. Herein, we summarize the novel molecular signals linking metabolism and male reproductive function with a focus on leptin signaling, mitochondria and relevant pathways for the nutritional support of spermatogenesis.