Effects of high-fat diet and treadmill running on the hypothalamic Kiss-1-GPR54 signaling pathway in male growing rats

Exploring the non-linear association and threshold effect of sedentary behavior on testosterone deficiency

BACKGROUND

Sedentary behavior has emerged as a potential risk factor for various health issues, including hormonal imbalances like testosterone deficiency (TD). However, the relationship between sedentary time and TD remains underexplored, especially with respect to the complex biological mechanisms underlying this association. This study aimed to examine the association between sedentary time and TD in adult males.

METHODS

This cross-sectional study analyzed data from the National Health and Nutrition Examination Survey 2011-2016. A total of 6057 male participants aged 20 years and older were included. Sedentary time was categorized into quartiles, and TD was defined as serum testosterone levels below 300 ng/dL. Logistic regression models were employed to assess the association between sedentary time and TD, adjusting for demographic, lifestyle, and health-related covariates. Restricted cubic spline (RCS) analysis and segmented regression were also conducted to explore potential non-linear relationships and thresholds. Subgroup analyses were performed to examine the consistency of associations across various groups.

RESULTS

The analysis revealed a significant positive association between sedentary time and TD. Prolonged sedentary behaviour was consistently associated with higher odds of TD across all models (all p < 0.001). RCS analysis showed a significant non-linear relationship, particularly as sedentary time exceeded 4.5 h per day, with a marked increase in the likelihood of TD (p-non-linear = 0.027). Subgroup analysis indicated that this association was most pronounced in Non-Hispanic Whites, current smokers, and drinkers, and was weaker in individuals with diabetes, where the association lost statistical significance after full adjustment.

CONCLUSIONS

This study identifies a significant association between prolonged sedentary behaviour and a higher risk of TD, suggesting that sedentary behavior may play a key role in the development of TD, particularly in specific high-risk populations.

Effects of chronic exposure to a high fat diet, nutritive or non-nutritive sweeteners on hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) axes of male Sprague-Dawley rats

PURPOSE

Diet-related factors are of great significance in the regulation of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonad (HPG) axes. In this study, we aimed to investigate the effects of chronic exposure to a high fat diet (HFD), fructose or sucralose on the endocrine functions.

METHODS

Male, Sprague-Dawley rats received a normal chow diet, HFD, 10% fructose or 0.02% sucralose for 10 weeks. Behavioral changes were assessed by open field (OFT) and elevated plus-maze (EPM) tests at week 8. H&E staining was used to observe pathological changes in adrenal cortex, testis and perirenal adipose tissue. Serum hormone concentrations were quantified via enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of genes along the HPA and HPG axes were determined using real-time PCR.

RESULTS

All types of dietary interventions increased body weight and disturbed metabolic homeostasis, with anxiogenic phenotype in behavioral tests and damage to cell morphology of adrenal cortex and testis being observed. Along the HPA axis, significantly increased corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) concentrations were observed in the HFD or 0.02% sucralose group. For HPG axis, gonadotropin-releasing hormone (GnRH) and estradiol (E2) concentrations were significantly increased in all dietary intervention groups, while decreased concentrations of follicle-stimulating hormone (FSH) and testosterone (T) were also detected. Moreover, transcriptional profiles of genes involved in the synthesis of hormones and corresponding hormone receptors were significantly altered.

CONCLUSION

Long-term consumption of HFD, fructose or sucralose manifested deleterious effects on endocrine system and resulted in the dysregulation of HPA and HPG axes.

Impact of Perinatal Coexposure to Chlorpyrifos and a High-Fat Diet on Kisspeptin and GnRHR Presence and Reproductive Organs

Emerging evidence has indicated the involvement of extrahypothalamic Kisspeptin and GnRHR in reproductive function. In this study, we evaluate if maternal exposure to the pesticide chlorpyrifos (CPF) and/or a high-fat diet (HFD) has an impact on the expression of Kisspeptin and GnRHR in the reproductive organs of rats' offspring. A total of 16 pregnant rats are divided into four groups: a control group (n = 4), CPF group (4 rats exposed daily to 1/mg/kg/day), HFD group (4 rats randomly fed a 5.25 kcal/g HFD), and coexposed group (4 rats exposed to CPF and HDF). At postnatal development postnatal day (PND) 60, male and female offspring were sacrificed. The reproductive organs (ovary and testis) were removed, and histological and immunohistological analysis and in silico quantification (TissueGnostics software 6.0.1.102, TissueFAXS, HistoQuest) were applied to investigate the impact of different treatments on Kisspeptin and GnRHR expression in reproductive organs. The main outcomes of the study showed a significant decrease in rat offspring's body weight in the CPF group from PND30 and PND60 (p < 0.05 and p < 0.01, respectively). Histological analysis showed a significant increase in the atretic follicle and abnormal testis structure with germ cell desquamation in the CPF-exposed group. The immunodetection quantification of protein shows a significant decrease in GnRHR and Kisspeptin in the HFD and CPF exposed groups, respectively, in testis rat offspring. Perinatal exposure to CPF and HFD exposure affect the reproduction function of rat offspring.