The pituitary-gonadal axis in men with protein-calorie malnutrition

Male reproductive hormones in patients treated with pretomanid

BACKGROUND:

Pretomanid (Pa) is a nitroimidazole-class drug recently approved by the US Food and Drug Administration and other regulatory authorities as part of a regimen for treating highly drug-resistant pulmonary Mycobacterium tuberculosis infections. Studies in rodents identified the testis as a target organ of concern, which led to monitoring of reproductive hormones in >800 male patients enrolled in four clinical trials of Pa-containing regimens and the HRZE (isoniazid+rifampin+pyrazinamide+ethambutol) control regimen.

METHODS:

Serum hormone levels relevant to male reproductive health – follicle stimulating hormone (FSH), luteinizing hormone (LH), inhibin B (InhB) and total testosterone (T) – from the four clinical trials were summarized numerically and analyzed by repeated-measures modeling.

RESULTS:

Hormone levels generally behaved similarly in Pa-containing and HRZE arms. Relative to baseline, serum T and InhB levels generally increased at the end of treatment and follow-up. FSH and LH levels were variable, but were generally at or below baseline levels by follow-up. Before treatment, many patients were borderline hypogonadal, with T levels near the lower limits of the normal range.

CONCLUSION:

Changes in male hormones in four clinical trials studying patients with TB indicate that Pa-containing treatment was not associated with testicular toxicity but rather led to improvement in the underlying hypogonadism.

Ground squirrels initiate sexual maturation during hibernation

Adequate nutrition is essential for normal reproductive function, which is vital for species to survive. In humans and other mammals, starvation and undernutrition deplete fat reserves and cause weight loss, attenuating the function of the reproductive axis and causing hypogonadism.^1-4 Thirteen-lined ground squirrels (Ictidomys tridecemlineatus) spend 7 months of every year in hibernation without food and water. Hibernating squirrels alternate between periods of torpor and interbout arousal (IBA), when animals temporarily return to an active-like state.⁵ The physiological significance of IBA is unclear, but it is thought to be essential for hibernation in animals that drop their body temperature to 2°C-4°C during torpor. Here, we report that juvenile male ground squirrels initiate reproductive maturation during their first hibernation season, despite prolonged undernutrition and profound weight loss. We show that the hypothalamic reproductive axis undergoes activation during interbout arousals in the middle of hibernation, triggering production of luteinizing hormone and testosterone, and promoting testicular growth. Initiation of sexual maturation is circannually entrained and is independent of physiological state, ambient temperature, and food availability. Our study suggests a role for interbout arousals during hibernation and uncovers the neurophysiological mechanism of reproductive axis activation during conditions of extreme negative energy balance.

Dysregulation of the Hypothalamic-Pituitary-Testicular Axis due to Energy Deficit

CONTEXT

Although gonadal axis dysregulation from energy deficit is well recognized in women, the effects of energy deficit on the male gonadal axis have received much less attention.

EVIDENCE ACQUISITION

To identify relevant articles, we conducted PubMed searches from inception to May 2021.

EVIDENCE SYNTHESIS

Case series and mechanistic studies demonstrate that energy deficit (both acutely over days or chronically over months) either from inadequate energy intake and/or excessive energy expenditure can lower serum testosterone concentration as a result of hypothalamic-pituitary-testicular (HPT) axis dysregulation in men. The extent to which this has clinical consequences that can be disentangled from the effects of nutritional insufficiency, concomitant endocrine dysregulation (eg, adrenal and thyroid axis), and coexisting comorbidities (eg, depression and substance abuse) is uncertain. HPT axis dysfunction is primarily the result of loss of GnRH pulsatility resulting from a failure of leptin to induce kisspeptin signaling. The roles of neuroendocrine consequences of depression, hypothalamic-pituitary-adrenal axis activation, proinflammatory cytokines, Ghrelin, and genetic susceptibility remain unclear. In contrast to hypogonadism from organic pathology of the HPT axis, energy deficit-associated HPT dysregulation is functional, and generally reversible by restoring energy balance.

CONCLUSIONS

The clinical management of such men should aim to restore adequate nutrition and achieve and maintain a healthy body weight. Psychosocial comorbidities must be identified and addressed. There is no evidence that testosterone treatment is beneficial. Many knowledge gaps regarding epidemiology, pathophysiology, and treatment remain and we highlight several areas that require future research.

Potential Intervention Targets in Utero and Early Life for Prevention of Hormone Related Cancers

Hormone-related cancers have long been thought to be sensitive to exposures during key periods of sexual development, as shown by the vulnerability to such cancers of women exposed to diethylstilbestrol in utero. In addition to evidence from human studies, animal studies using new techniques, such as gene knockout models, suggest that an increasing number of cancers may be hormonally related, including liver, lung, and bladder cancer. Greater understanding of sexual development has also revealed the "mini-puberty" of early infancy as a key period when some sex hormones reach levels similar to those at puberty. Factors driving sex hormones in utero and early infancy have not been systematically identified as potential targets of intervention for cancer prevention. On the basis of sex hormone pathways, we identify common potentially modifiable drivers of sex hormones, including but not limited to factors such as obesity, alcohol, and possibly nitric oxide. We review the evidence for effects of modifiable drivers of sex hormones during the prenatal period and early infancy, including measured hormones as well as proxies, such as the second-to-fourth digit length ratio. We summarize the gaps in the evidence needed to identify new potential targets of early life intervention for lifelong cancer prevention.

Gynaecomastia--pathophysiology, diagnosis and treatment

Gynaecomastia (enlargement of the male breast tissue) is a common finding in the general population. Most cases of gynaecomastia are benign and of cosmetic, rather than clinical, importance. However, the condition might cause local pain and tenderness, could occasionally be the result of a serious underlying illness or a medication, or be inherited. Breast cancer in men is much less common than benign gynaecomastia, and the two conditions can usually be distinguished by a careful physical examination. Estrogens are known to stimulate the growth of breast tissue, whereas androgens inhibit it; most cases of gynaecomastia result from deficient androgen action or excessive estrogen action in the breast tissue. In some cases, such as pubertal gynaecomastia, the breast enlargement resolves spontaneously. In other situations, more active treatment might be required to correct an underlying condition (such as hyperthyroidism or a benign Leydig cell tumour of the testis) or medications that could cause breast enlargement (such as spironolactone) might need to be discontinued. For men with hypogonadism, administration of androgens might be helpful, as might antiestrogen therapy in men with endogenous overproduction of estrogens. Surgery to remove the enlarged breast tissue might be necessary when gynaecomastia does not resolve spontaneously or with medical therapy.

Ursodeoxycholic acid alleviates cholestasis-induced histophysiological alterations in the male reproductive system of bile duct-ligated rats

Ursodeoxycholic acid is the most widely used drug for treating cholestatic liver diseases. However, its effect on the male reproductive system alterations associated with cholestasis has never been studied. Thus, this study aimed to investigate the effect of ursodeoxycholic acid on cholestasis-induced alterations in the male reproductive system. Cholestasis was induced by bile duct ligation. Bile duct-ligated rats had higher cholestasis biomarkers and lower levels of testosterone, LH and FSH than did the Sham rats. They also had lower reproductive organs weights, and lower sperm motility, density and normal morphology than those of Sham rats. Histologically, these animals suffered from testicular tubular atrophy, interstitial edema, thickening of basement membranes, vacuolation, and depletion of germ cells. After ursodeoxycholic acid administration, cholestasis-induced structural and functional alterations were significantly ameliorated. In conclusion, ursodeoxycholic acid can ameliorate the reproductive complications of chronic cholestasis in male patients, which represents an additional benefit to this drug.

Clinical study of Tribulus terrestris Linn. in Oligozoospermia: A double blind study

Infertility is a problem of global proportions, affecting on an average 8-12% of couples worldwide. Low sperm count (Oligozoospermia) is one of the main causes of male infertility and it is correlated with Kshina Shukra. The fruits of Gokshura (Tribulus terrestris. Linn) are considered to act as a diuretic and aphrodisiac; they used for urolithiasis, sexual dysfunctions, and infertility. Hence, it was planned to study the effect of Gokshura in the management of Kshina Shukra (Oligozoospermia), and to evade the preconception, a double-blind, randomized, placebo-controlled study was designed. In this study, eligible subjects between the age of 21 and 50 years, with a complaint of Kshina Shukra (Oligozoospermia), were randomized to receive either Gokshura granules or placebo granules for 60 days. The primary outcome measures were percentage changes in the Pratyatmaka Lakshanas (cardinal symptoms) of Kshina Shukra, Agni bala, Deha bala, Satva bala, the semenogram, and in the Quality of the Sexual Health Questionnaire. The placebo granules showed 70.95% improvement, whereas, the Gokshura granules showed 78.11% improvement in Rogi bala (Agni bala, Deha bala, Satva bala, and the Quality of Sexual Health) and Rogabala (Semen Analysis and Pratyatmaka Lakshanas). The Gokshura granules have shown superior results in the management of Kshina Shukra, as compared to the placebo granules.

Testosterone positively associated with both male mating effort and paternal behavior in Savanna baboons (Papio cynocephalus)

Testosterone (T) is often positively associated with male sexual behavior and negatively associated with paternal care. These associations have primarily been demonstrated in species where investment in paternal care begins well after mating activity is complete, when offspring are hatched or born. Different patterns may emerge in studies of species where investment in mating and paternal care overlap temporally, for instance in non-seasonal breeders in which males mate with multiple females sequentially and may simultaneously have multiple offspring of different ages. In a 9-year data set on levels of T in male baboons, fecal concentrations of T (fT) were positively associated with both mate guarding ("consortship") - a measure of current reproductive activity - and with the number of immature offspring a male had in his social group - a measure of past reproductive activity and an indicator of likely paternal behavior. To further examine the relationship between T and potential paternal behavior, we next drew on an intensive 8-month study of male behavior, and found that fathers were more likely to be in close proximity to their offspring than expected by chance. Because male baboons are known to provide paternal care, and because time in proximity to offspring would facilitate such care, this suggests that T concentrations in wild male baboons may be associated with both current reproductive activity and with current paternal behavior. These results are consistent with the predicted positive association between T and mating effort but not with a negative association between T and paternal care; in male baboons, high levels of T occur in males that are differentially associating with their offspring.

Effect of sexual dimorphism on muscle strength in cachexia

BACKGROUND

Reduced muscle strength is a cardinal feature in cachexia. We investigated whether weight loss is associated differently with muscle strength in men and women in a large cohort of hospitalized patients.

METHODS

One thousand five hundred hospitalized patients (whereof 718 men, mean age 57.6 ± 16.0 years, mean body mass index (BMI) 24.6 ± 4.8 kg/m²) were included in the study. Non-edematous involuntary weight loss was determined with Subjective Global Assessment; isometric maximal muscle strength was evaluated by hand grip strength. Mid-upper arm circumference and triceps skinfold were used to calculate arm muscle area. Interrelationship between sex and weight loss was evaluated by regression analysis performed with the general linear model (GLM) allowing adjustment for continuous and categorical variables and corrected for age, arm muscle area (AMA), BMI, and diagnosis category (benign/malignant disease) as potentially confounding covariates.

RESULTS

Both men and women exhibited a significant stepwise decrease of hand grip strength with increasing weight loss. Age, sex, moderate and severe weight loss, BMI, and AMA were significant predictors of hand grip strength. The GLM moreover revealed a significant sex × weight loss effect, since grip strength was similarly decreased in moderate weight loss in men and women when compared to control patients without weight loss (8.5% in men and 10.5% in women, not significant (n.s.)), but the further reduction of grip strength in severe weight loss was significantly different between men and women (10.6% vs. 4.1%, P = 0.033).

CONCLUSIONS

Our findings indicate sex-specific differences in muscle strength response to weight loss.

Hormonal disturbances in visceral leishmaniasis (kala-azar)

This study presents a cross-sectional analysis of the hormonal alterations of patients with visceral leishmaniasis. The diagnosis was established by the bone marrow aspiration and polymerase chain reaction test. Primary adrenal insufficiency was observed in 45.8% of patients; low aldosterone/renin plasma ratio in 69.4%; low daily urinary aldosterone excretion in 61.1%; and low transtubular potassium gradient in 68.0%. All patients had normal plasma antidiuretic hormone (ADH) concentrations, hyponatremia, and high urinary osmolality. Plasma parathyroid hormone was low in 63%; hypomagnesemia was present in 46.4%, and increased Mg(++)(EF) in 100%. Primary thyroid insufficiency was observed in 24.6%, and secondary thyroid insufficiency in 14.1%. Normal follicle-stimulating hormone plasma levels were present in 81.4%; high luteinizing hormone and low testosterone plasma levels in 58.2% of men. There are evidences of hypothalamus-pituitary-adrenal axis abnormalities, inappropriate aldosterone and ADH secretions, and presence of hypoparathyroidism, magnesium depletion, thyroid and testicular insufficiencies.

Endocrinology of year-round reproduction in a highly seasonal habitat: environmental variability in testosterone and glucocorticoids in baboon males

In conditions characterized by energetic constraints, such as in periods of low food availability, some trade-offs between reproduction and self-maintenance may be necessary; even year-round breeders may then be forced to exhibit some reproductive seasonality. Prior research has largely focused on female reproduction and physiology, and few studies have evaluated the impact of environmental factors on males. Here we assessed the effects of season and ambient temperatures on fecal glucocorticoid (fGC) and testosterone (fT) levels in male baboons in Amboseli, Kenya. The Amboseli basin is a highly challenging, semiarid tropical habitat that is characterized by strongly seasonal patterns of rainfall and by high ambient temperatures. We previously reported that female baboons were impacted by these challenging environmental conditions. We ask here whether male baboons in the same environment and groups as females exhibit similar physiological effects. We found that after accounting for male age and individual variability, males exhibited higher fGC levels and lower fT levels during the dry season than during the wet season. Furthermore, fT but not fGC levels were lower in months of high average daily maximum temperatures, suggesting a direct impact of heat on testes. Our results demonstrate that male baboons, like females, experience ecological stress that alters their reproductive physiology. The impact of the environment on male reproduction deserves more attention both in its own right and because alteration in male physiology may contribute to the reduction in female fertility observed inchallenging environments.

Gynecomastia

Gynecomastia is common and may be asymptomatic. In most cases, a thorough history and physical examination, along with limited laboratory investigations, can help to exclude breast malignancy and serious underlying endocrine or systemic disease. Careful clinical observation may be all that is required in many cases, because gynecomastia often resolves spontaneously. Because gynecomastia is usually caused by an imbalance of androgenic and estrogenic effects on the breast, medical therapy may include antiestrogens, androgens, or aromatase inhibitors. Surgery is useful in the management of patients with long-standing symptomatic gynecomastia or when medical therapy is not successful.

Reproductive maturation, somatic growth and testosterone among Zimbabwe boys

BACKGROUND

Little is known about the role of energetic status in the timing of puberty among males across populations.

AIM

To determine the relationship of testosterone production and bioavailability to energetic status and somatic growth in a sub-Saharan population.

SUBJECTS AND METHODS

Anthropometric measures, secondary sexual characteristics, blood spot and salivary samples were obtained from 441 Zimbabwe school boys, aged 12-18, from four high schools in the Harare area.

RESULTS

Salivary and blood testosterone both showed their first significant increase between 14 and 15 years of age. Both salivary and blood testosterone were positively related to subscapular, but not triceps skinfold, when controlled for Tanner genital stage and age. Controlled for Tanner genital stage and age, salivary, but not blood testosterone was related to suprailiac skinfolds. Blood testosterone, but not salivary testosterone, showed a significant relationship with Tanner genital stage, controlled for age and suprailic skinfolds. Blood and salivary testosterone showed similar relationships with height and arm muscle plus bone area.

CONCLUSION

These results provide support for the hypothesis that energetic status, especially abdominal fat plays a role in bioavailable testosterone during male puberty. However, they fail to demonstrate a clear effect of bioavailable testosterone on somatic growth.

Low salivary cortisol and elevated depressive affect among rural men in Botswana: reliability and validity of laboratory results

Most research on hypothalamic-pituitary-adrenal axis function under aversive conditions has focused on relatively increased acute episodic, or chronic secretions as an operationalization of "stress." Severe or recurrent stress, perhaps in interaction with individual characteristics, results in chronically decreased HPA function among some persons suffering from posttraumatic stress disorder. Little evidence exists to assess the population distribution of chronic low cortisol in different free-ranging human populations, as a manifestation of past trauma or stress. This study reports findings of chronically depressed ambulatory salivary cortisol among rural-dwelling Batswana men (n=30) compared with men living in Gaborone (n=34), the capital of Botswana, based on repeated ambulatory sampling. Out of 914 saliva samples analyzed by radioimmunoassay, 268 (29.3%) samples (41 urban, 227 rural) were below the minimum detectable dose (<MDD of 0.034 ug/dL) of the assay. Low values were distributed across comparable times of day as were =MDD samples. There was significant clustering of low cortisol within individuals; percentage of intra-individual repeats that were <MDD ranged from zero to 94.1% for rural participants (median=59.8%; mean=54.8%; SD=27.8%), and from zero to 40% for urban (median=0%; mean=8%; SD=11.9%). There was no association between number of repeats and proportion <MDD (P[F=-0.47]=0.639; beta(1)=-0.0045+/-0.0019). Examination of laboratory quality control suggests that this pattern is not a result of measurement error, or poor sample preservation, but instead reflects a difference from residing in a remote rural versus a central urban community.

Adaptive variation in testosterone levels in response to immune activation: empirical and theoretical perspectives

High testosterone levels reflect investment in male reproductive effort through the ability to produce and maintain muscle tissue and thus augment mate attraction and competitive ability. However, high testosterone levels can also compromise survivorship by increasing risk of prostate cancer, production of oxygen radicals, risk of injury due to hormonally-augmented behaviors such as aggression, violence and risk taking, reduced tissue and organ maintenance, negative energy balance from adipose tissue catabolism, and suppression of immune functions. Here, I briefly discuss how inter- and intra-individual variation in human male testosterone levels is likely an adaptive mechanism that facilitates the allocation of metabolic resources, particularly in response to injury, illness or otherwise immune activation. Maintaining low testosterone levels in resource-limited and/or high pathogen-risk environments may avoid some immunosuppression and suspend energetically-expensive anabolic functions. Augmenting testosterone levels in the presence of fertile and receptive mates, areas of high food resource availability, and low disease risk habitats will function to maximize lifetime reproductive success.

Age-related patterns of urinary gonadotropins (FSH and LH) and E-3-G as measures of reproductive function among Turkana males of northern Kenya

To determine age-related patterns of gonadotropins and their relationship to energetic status in a subsistence population we analyzed urinary FSH, LH, and estrone-3-glucuronide (E-3-G) along with anthropometric measures among Turkana males of northern Kenya. Subjects were 134 nomadic and 109 settled males ages 20 to 80+. FSH, LH and E-3-G were significantly higher among the settled, compared to nomadic, males. LH, but not FSH, showed a significant increase across 10 year age groups among all the men. E-3-G increased across age groups only among the settled males. Controlled for age, FSH was inversely related to measures of fat free and body mass among the settled men. These findings suggest an unusual age profile of gonadotropins and estrogen metabolites that may reflect the impact of fluctuating food availability. More research is needed to address the impact of energetic and social factors on the male reproductive axis among energetically stressed populations.

Gonadal dysfunction in systemic diseases

Gonadal function is significantly affected in many acute and chronic systemic diseases. As the function of the testes and the ovaries is determined by the integrity of the hypothalamic-pituitary-gonadal axis, it is obvious that a systemic disease may affect one or more levels of the axis in such a manner that the gonadal dysfunction may have various clinical and laboratory manifestations. In this brief review, the most common disturbances seen in the main systemic diseases will be discussed.

Age-related differences in serum gonadotropin (FSH and LH), salivary testosterone, and 17-? estradiol levels among Ache Amerindian males of Paraguay

Age-related differences in serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), salivary testosterone, and 17-beta estradiol levels are reported for Ache Amerindian males (n = 17; mean age, 37.1 +/- 14.2 SD) of Paraguay in order to explore population variation in patterns of male reproductive senescence in a foraging/agricultural community. Hormone associations were examined to test various hypotheses for age-related differences in hypothalamic-pituitary function. Significant increases in FSH (r = 0.75, P < 0.0005) and LH (r = 0.65, P < 0.01) were noted in association with aging. No significant correlation was observed between morning or evening testosterone and age. Morning and evening estradiol levels were associated with morning and evening testosterone, respectively (morning, r = 0.53, P = 0.05; evening, r = 0.63, P = 0.02). Evening estradiol was also positively associated with LH (r = 0.66, P = 0.02), suggesting testicular production to be an important source of circulating estradiol. Morning estradiol tended to rise with age, but was not significant (r = 0.39, P = 0.15). Anthropometric measurements of height, weight, body mass index, and fat percent did not change significantly with age. In contrast to testosterone, age-related differences in gonadotropin levels may be independent of energetic status, less variant, and more universal among male populations. Implications for gonadotropin function and aging on human male reproductive senescence and life histories are discussed.

Salivary testosterone and body composition among Ariaal males

To determine if testosterone is negatively related to acute and/or chronic nutritional status among men in a subsistence society, saliva samples and anthropometric measures were compared among nomadic and settled Ariaal pastoralists of northern Kenya. Fifty-six nomadic men and 62 settled men facing drought conditions, estimated ages 22-96 years, were sampled. Measures included height, weight, four skinfolds, and %body fat by bioelectric impedance (BIA). Saliva samples were assayed for testosterone using radioimmunoassay. Overall, both body mass index (BMI) (avg. = 17.8 +/- 6.0 kg/m(2)) and salivary testosterone (T) levels (avg. am value = 176.8 +/- 74.8 pmol/l) were low compared to values from Western populations. Comparison of the two subpopulations revealed no significant difference in height, weight, BMI, or lean body mass. However, nomadic males exhibited significantly smaller skinfolds. Evening, but not morning, salivary T values differed between the subpopulations. Age-related changes in body composition included a significant decline in BMI with age, related to loss of body fat, but with little change in lean body mass. Age-related declines in BMI and %body fat were more pronounced among the nomadic males. am salivary T values declined with age; again, the decline was significantly greater among nomadic males. pm salivary T levels showed no significant decline with age. When controlled for residence and age, salivary T was positively related to %body fat and WHR ratio, but not lean body mass. These results provide evidence that salivary T is related to acute nutritional status among males in an energetically stressed subsistence population, in accordance with life history theories of somatic allocation.

Serum leptin levels and anthropometric correlates in Ache Amerindians of eastern Paraguay

Leptin is a recently discovered peptide hormone secreted primarily from adipocytes in humans and other mammals; it is a reflection of fat stores, and has been associated with reproductive function. However, few leptin measurements are available from nonindustrialized populations, including contemporary hunter/gatherer communities undergoing the transition to sedentary agriculture. This investigation reports single-sample serum leptin measurements in healthy Ache Amerindian males (n = 21; average age, 32.8 +/- 3.4 SE) and females (n = 12; average age, 31.3 +/- 4.3) in eastern Paraguay. Ache leptin concentrations were much lower than in industrialized populations, although significant sexual dimorphism was evident (female 5.64 ng/ml +/- 0.91 SE vs. male 1.13 ng/ml +/- 0.08; P < 0.0001). Indeed, female leptin levels were similar to those of anorexic women, despite apparently adequate adiposity. Controlling for fat percentage, no significant sex difference was evident, suggesting that adiposity was the primary source of leptin variation. Body fat percentage was highly correlated with leptin in females (r2 = 0.72; P < 0.0005) but not males, who exhibited a modest negative correlation (r2 = 0.25; P < 0.03). Weight (r2 = 0.45; P = 0.02) and BMI (kg/m2) (r2 = 0.81; P < 0.0001) were also significantly correlated in females but not males. These results suggest that: 1) clinical leptin norms based on industrialized populations may represent the highest range of human variation and may not be representative of most human populations; 2) hormonal priming may underlie population variation in leptin profiles; and 3) the relative importance of leptin as a proximate mechanism regulating reproductive effort during human evolution may have been modest.

Differences between men and women as regards the effects of protein-energy malnutrition on the hypothalamic-pituitary-gonadal axis

Although protein-energy malnutrition (PEM) affects 50% of hospitalized patients, its effects on the hypothalamic-pituitary-gonadal (HPG) axis have not been extensively investigated. To investigate the effects of PEM on the HPG axis in hospitalized patients, 62 inpatients ages 18-91 y (35 men and 27 women) had a nutritional and hormonal evaluation. Hormones were determined in blood samples obtained between 0700 and 1200 h. Patients were divided into two subgroups: those with body mass index (BMI) <18.5 kg/m2 (low body mass index [LBMI]; 16 men, 13 women) and those with BMI >20 kg/m2 (normal-high body mass index [NHBMI]; 19 men, 14 women). The nutritional parameters of LBMI patients were inferior to those of NHBMI patients. Total and free testosterone levels were subnormal, 31.4% and 17.2% respectively, in all men; free testosterone was subnormal in 31.25% of LBMI versus 5.3% of NHBMI male patients and total testosterone concentration was subnormal in 43.8% of LBMI versus 21.1% of NHBMI male patients. Luteinizing hormone (LH) level was higher in LBMI men than in NHBMI men, whereas the reverse was the case for women, for whom follicle-stimulating hormone (FSH) also was lower in the LBMI group than the NHBMI group. The HPG axis hormones which best discriminated between the LBMI and NHBMI groups were free testosterone for men and LH and FSH for women, which were all lower in the LBMI than in the NHBMI group. LH was correlated with BMI and midupper arm muscle circumference (AMC) (women positively and men negatively) but not with triceps skin-fold thickness (TSF). Total testosterone level was positively correlated with AMC and free testosterone with TSF. Hypogonadism is common among hospitalized patients with PEM. Men with PEM have low testosterone levels with normal or high gonadotropin levels, which suggests impairment of Leydig cell function. Women with PEM suffer hypogonadotropic hypogonadism. AMC correlates positively with total serum testosterone concentration in men and with LH levels in women, suggesting that satisfactory function of the HPG axis requires a functional (protein) reserve as well as an energy (fat) reserve.

Testicular Pathologic Changes and the Pituitary-Testicular Axis During Human Immunodeficiency Virus Infection

OBJECTIVE

To chronicle pituitary-testicular axis dysfunction and its clinicopathologic features in homosexual men.

METHODS

Between 1984 and 1992, 84 homosexual men underwent longitudinal follow-up for 4 years. At entry into the study, 28 were seronegative and 56 were seropositive for human immunodeficiency virus (HIV). Although 40 subjects remained asymptomatic (nonprogressors), 16 had progression to acquired immunodeficiency syndrome (AIDS). Of those 16 patients with progression, 8 had AIDS within 2 years (early progressors) and 8 demonstrated AIDS within 4 years after enrollment (late progressors), and all died. The testes of five patients were examined at autopsy. The control group had similar follow-up. Luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and bioavailable testosterone (bio-T) were measured in stored sera collected at 2-year intervals. The last hormonal measurement was between 3 and 24 months before autopsy. Comparison was made between autopsied and nonautopsied patients with AIDS as well as between HIV nonprogressors and control seronegative men. The correlation between pathologic findings and hormonal status was examined by regression analysis.

RESULTS

At baseline, testosterone, bio-T, LH, and FSH were not significantly different among all patients and subjects. During the study period, testosterone, bio-T, and serum gonadotropin levels remained unchanged in the seronegative homosexual men. In nonprogressors, serum FSH and LH concentrations remained unchanged, whereas testosterone and bio-T levels decreased significantly during this 4-year period. After progression to AIDS (in both groups of progressors), the serum FSH and LH levels were higher and the serum testosterone and bio-T were lower in comparison with values in the seronegative men. In late progressors to AIDS, FSH and LH increased, whereas serum testosterone and bio-T decreased significantly from baseline. All five patients with AIDS on whom autopsy was done had boundary wall thickening of the seminiferous tubules and decreased spermatogenesis. No significant differences were found in serum testosterone, bio-T, and LH between those in whom autopsy was or was not done; however, FSH was significantly higher in the autopsied cases. The serum testosterone and bio-T levels were negatively correlated with the interstitial inflammation. A significant correlation was also observed between change of bio-T and weight loss.

CONCLUSION

We conclude that dysfunction of the pituitary-gonadal axis is common in HIV-infected men. All patients in whom autopsy was done because of AIDS-related diseases had been hypogonadal 3 to 24 months before death. Decreased spermatogenesis, subacute interstitial inflammation, or both were seen at autopsy of patients with AIDS. Pathologic damage to the testes during AIDS was associated with decreased testosterone and bio-T as well as increased serum gonadotropin levels. In a substantial proportion of men with progression to AIDS, compensated hypogonadism (normal serum testosterone and increased serum LH levels) preceded the development of low serum testosterone level.

Reproductive effects of nontesticular illness

Diseases in other organs may impair the male reproductive system. Acute critical conditions such as severe trauma, surgery, myocardial infarction, burns, liver failure, intoxication, or starvation are associated with suppression of gonadotropin secretion and secondary hypogonadism. With chronic illnesses, a primary testicular disorder with elevated gonadotropin levels may occur. This may be associated with increased peripheral conversion of androgens to estrogens, resulting in clinical presentation of combined androgen deficiency and estrogen excess. The association of hypogonadism and feminization with cirrhosis of the liver is a classic example. Types of hypogonadism that may occur with chronic anemia, chronic renal failure, chronic spinal cord injury, thyroid diseases, Cushing's syndrome, diabetes mellitus, obesity, HIV infection, neoplasia, and other chronic illnesses are also described. Numerous drugs have side effects on the reproductive system.

Androgen therapy in AIDS wasting

Hypogonadism in HIV-infected men has been well described, having a prevalence of about 30%. Its aetiology is a combination of non-specific changes from chronic and acute illness, and specific effects due to HIV infection. A depressed serum testosterone level has been associated with viral or infectious invasion of the endocrine organs, and with medications commonly used in treating HIV infection. Recently, many have noted the association between decreased serum testosterone in men and women, and the wasting syndrome of HIV infection, particularly with a reduction in lean body mass. Our understanding of the risks and benefits of testosterone therapy in non-HIV infected men has grown significantly. Treatment in this population can improve sexual function, quality of life parameters and body composition. Based on this information, a few studies have been carried out, and more are being planned to test the hypothesis that therapy with testosterone or its analogues can benefit HIV-infected men and women with wasting and/or low circulating androgen concentrations. To date, the studies have been inconclusive. Not all studies have shown a statistical benefit of androgen therapy on weight, muscle mass or quality of life. Testosterone is now available in several forms for dosing, which has improved compliance and ease of administration. Its potential risk to the prostate or serum lipids should be monitored closely. Although the beneficial effects of androgenic steroids in HIV-infected men have not been demonstrated clearly, short-term studies suggest that testosterone supplementation may improve metabolic outcomes in HIV-infected men with androgen deficiency.

Relationships between fasting plasma insulin, anthropometrics, and metabolic parameters in a very old healthy population. Associazione Medica Sabin

Several studies have shown that insulin resistance and hyperinsulinemia are associated with many metabolic disorders predisposing to coronary heart disease (CHD). This syndrome has been termed syndrome X. However, it is not completely known whether these relationships are still present in the elderly, or whether other factors such as age, gender, and body fat distribution modulate them. Therefore, we investigated the relationship between fasting plasma insulin, total and regional adiposity, fasting plasma glucose and lipids, plasma plasminogen activator inhibitor-1 (PAI-1), fibrinogen, and coagulation factor VII in a sample of 100 healthy free-living octogenarians-nonagenarians (52 men and 48 women) who were disability-free according to the Katz index. By univariate analysis, fasting insulin correlated positively with all anthropometric measures except the waist to hip ratio (WHR) in women. There was a positive correlation between fasting insulin and fasting glucose (r=.40, P < .01), plasma triglycerides ([TGs] r=.21, P < .05), and PAI-1 levels (r=.33, P < .01), whereas a negative relation was found with high-density lipoprotein cholesterol (HDL-C) and apolipoprotein, A-I (apo A-I) levels (r=-.22 and =-.24, respectively, P < .05). These relationships were weaker and less significant in women. In pooled data, stepwise multiple regression analysis showed an independent relationship of both the body mass index (BMI) and fasting insulin level with TGs (R2=.14), while gender and fasting insulin were the best predictors of HDL-C variance (R2=.17). Furthermore, fasting insulin was the only variable independently related to PAI-1 (R2=.12). Our findings support the existence of a metabolic syndrome even in very old age by showing that high insulin levels are related to various metabolic and hemostatic disorders.

Testosterone replacement treatment options for HIV-infected men

Hypogonadism is well documented in HIV-infected men, particularly as they progress to AIDS and in those with symptoms of wasting. Testosterone deficiency can be diagnosed with simple laboratory tests, and various treatment options exist. The benefits of androgen replacement are well documented from a large body of literature and experience with hypogonadal men without HIV infection. Hypogonadal men who are given testosterone replacement have improved sexual thoughts and functioning, more energy, and improved mood. Generally, quality of life improves with such therapy. Testosterone replacement tends to maintain or improve lean body mass. The benefit, dose, and timing of testosterone replacement treatment for men with HIV infection, however, are less clear and require further study. Appropriate history and a high degree of clinical suspicion, coupled with relatively simple laboratory measurements, can confirm the diagnosis of hypogonadism in men with HIV. Various options for testosterone replacement, including injections of testosterone esters and the use of transcutaneous patches, are discussed, as are the uses of pharmacologic doses of testosterone, primarily for its potential anabolic effect.

Intensive dance practice. Repercussions on growth and puberty

To determine the effect of intensive sports training on growth and puberty, we studied a group of 97 young female dancers longitudinally for 5 years. We studied the changes in their heights, weights, and pubertal developments and compared these findings with those of a control group. We found that 15 (16%) dancers who started dance training had noticeably decreased growth velocity during the prepuberty stage after the beginning of ballet practice compared with the control group. This group had the same average training time compared with the other dancers, but these dancers were the slimmest and had the most inadequate nutritional intake. Puberty in dancers was delayed compared with the controls. We found that moderately intensive dance practice can lead to eating disorders and weight control early in childhood, with consequences that are poorly known. Weight and height statistics of children who practice individual sports involving body aesthetics must be monitored to detect early anomalies.

Assessment of sperm motion characteristics in infertile renal transplant recipients using computerized analysis

A total of 34 kidney transplant recipients (18 infertile and 16 fertile) and 31 nontransplant persons (15 infertile and 16 fertile) were included in this study. All subjects were assessed clinically and by measurement of basal concentrations of total testosterone, FSH, cyclosporine whole blood trough levels, serum creatinine, haemoglobin and semen analysis using computer-aided sperm analysis (CASA) as well as scrotal ultrasonography to evaluate testicular dimensions. Our results demonstrate a significant decrease (p < 0.05) in sperm concentration, the percentage of motile spermatozoa, straight line velocity (VSL), linearity (LIN) and velocity of average path (VAP) among infertile transplant patients in comparison with the fertile transplant group. Serum testosterone, FSH levels and testicular dimensions did not differ significantly (p > 0.05) between fertile and infertile transplant recipients. Both sperm concentration and VSL were inversely correlated to the cyclosporine whole blood trough levels (p < 0.05). The time spent on haemodialysis was inversely correlated (p < 0.05) with the percentage of motile spermatozoa and the amplitude of lateral head displacement (ALH). In conclusion, CASA is valuable in evaluation of sperm motility in infertile renal transplant patients. Stabilization of the cyclosporine whole blood trough level within the target therapeutic level and correction of anaemia (if any) could improve the fertility potential in kidney transplant recipients.

Altered pulsatile gonadotropin signaling in nutritional deficiency in the male

Reproduction cannot occur without adequate nutrition. Diets that are nutritionally inadequate delay and disrupt the pubertal development of the reproductive processes of immature experimental animals and humans, and impair the function of the hypothalamic-pituitary-gonadal axis in adults. Although there is a general understanding of the linkages between nutrition and reproduction, there is a lack of detailed knowledge of the exact mechanisms that couple these two systems. The major effects of malnutrition on the hypothalamic-pituitary-gonadal axis reported in the literature are, for the most part, manifested as reduced gonadotropin secretion. Malnutrition results in decreased circulating gonadotropin concentrations. These changes in the reproductive system are associated with impaired gonadal function and subsequent secondary sex organ atrophy and lead, ultimately, to poor reproduction. Decreased hypothalamic release of gonadotropin-releasing hormone (GnRH) has been proposed as the most important etiologic factor for the fasting-induced suppression of pituitary-testicular function. In the human, hypogonadism and infertility develop in both sexes during chronic malnutrition. Most studies on the effects of malnutrition on the reproductive hormones have been performed in women, perhaps because malnutrition in women is promptly accompanied by amenorrhea, whereas in men hypogonadism develops gradually and becomes clinically evident only during more severe malnutrition. With the advent of sensitive assays for measuring reproductive hormones and of modern computerized methods for analyzing the pulsatile secretion of these hormones, however, the function of the hypothalamic-pituitary-testicular axis has been scrutinized and it has, indeed, been observed that this system is disturbed even during acute malnutrition. Here, we review the effects of malnutrition on reproductive function, especially on the pulsatile pattern of LH secretion, in humans and in experimental animals.

Relative and combined effects of ethanol and protein deficiency on gonadal function and histology

The aim of the present study is to analyse the relative and combined effects of ethanol and protein deficiency on serum testosterone and LH, and on gonadal histology, in ethanol fed rats. The study was performed in 32 animals divided into four groups, fed with the Lieber & DeCarli control, 36% ethanol, 2% protein, and 36% ethanol 2% protein containing diets, respectively. Two months later, rats were anaesthetized with pentobarbital and sacrificed, and the right testes and epididymus were carefully removed. Both ethanol and protein deficiency independently lead to a decrease in serum testosterone levels, and to testicular atrophy, lowest testosterone levels and highest degrees of atrophy being observed in the rats receiving the 36% ethanol, 2% protein containing diet. Both serum testosterone and testicular size and weight significantly correlated with final weight and serum albumin. Hypospermia, atrophy of the seminiferous tubules, and reduced epididymal diameter were also observed in this last group of animals. Thus, protein deficiency may contribute to hypogonadism of alcoholics.

Pituitary-gonadal dysfunction in male patients with lung cancer. Association with serum inhibin levels

Male lung cancer patients with poor performance status have an endocrinological dysfunction shown by decreased serum levels of total and free testosterone (AFTC). The intention was to investigate whether or not inhibin plays a role in gonadal dysfunction observed in male patients with malignant pulmonary disease. Twenty-seven patients with locally advanced non-small cell lung cancer were included. Sixteen patients were within ECOG index 1-2 (group A) and 11 patients within ECOG index 3-4 (group B). Gonadal function was monitored by serum LH, FSH, testosterone, SHBG and inhibin levels. Patients with poor performance status displayed significantly lower inhibin (1.6 +/- 0.8 U/I) and AFTC (0.23 +/- 0.07 nmol/l) levels when compared to patients within ECOG index 1-2 (inhibin 2.4 +/- 1.1 U/I; AFTC 0.66 +/- 0.36 nmol/l). Serum inhibin tended to correlate inversely to FSH with a 4.4-fold higher FSH/inhibin ratio in group B compared to A.

Reversal of sexual impotence in male patients with chronic obstructive pulmonary disease and hypoxemia with long-term oxygen therapy

Erectile impotence is commonly encountered in male patients with respiratory failure and hypoxia. In this study, 42% of the patients experienced reversal of sexual impotence during long-term oxygen therapy (LTOT). We examine the association between sexual impotence, gonadal axis hormones, hypoxia, and oxygen therapy. Nineteen sexually impotent male patients eligible for LTOT (pO2 < 7.3 kPa during stable disease) and with sexual impotence received oxygen therapy for 1 month (n = 12) or 24 h (n = 7). pO2, LH, FSH, testosterone, and SHBG (sex hormone binding globulin) were monitored. Five of 12 patients receiving oxygen for 1 month regained sexual potency. The responders showed a significant increase in arterial pO2 and serum testosterone, and a decline in SHBG compared to non-responders. None of the patients receiving oxygen for 24 h experienced reversal of sexual impotence, despite a significant increase in pO2. In these patients, serum testosterone did not increase significantly. Reversal of sexual impotence may be achieved in some patients with respiratory failure. The oxygen therapy must, however be administered for an adequate length of time.

Exercise and male factor infertility

Recent advances in the study of andrology are unfolding some of the idiopathic components of male factor infertility. The inclusion of exercise training as a component of male factor infertility has been proposed secondary to changes observed in the reproductive hormone and semen profile of some endurance trained male athletes. Evidence exists that a subset of endurance trained men, particularly runners, present with subclinical changes in their reproductive hormone profile. These changes include a reduction in total and free testosterone, alterations in luteinising hormone release and alterations in pituitary responses to gonadotrophin-releasing hormone and other pharmacological perturbations. Less attention has been directed towards identifying changes in spermatogenesis and fertility capacity as a result of endurance training. The semen ejaculate of some endurance trained athletes presents with nonspecific modifications including a low normal sperm count, decreased motility and several morphological changes that may compromise fertility. Thus, although a subset of high mileage endurance trained runners present with subclinical modifications in their reproductive hormone and semen profile, to date there is no evidence that endurance training causes male infertility. Future investigations should focus on the clinical impact these hormone and semen alterations may have on fertility capacity in endurance trained athletes.

Endocrine abnormalities in mitochondrial myopathy with external ophthalmoplegia

Endocrine functions were examined in 21 patients with mitochondrial myopathies presenting with chronic progressive external ophthalmoplegia and other additional neurological and multisystemic symptoms. Ten patients had the features of the Kearns-Sayre syndrome. Deletions of the mitochondrial DNA were found in 4 out of 5 patients examined. Fourteen patients, including 3 with deletions of the mitochondrial DNA, had various and often multiple endocrine abnormalities: 6 patients were of short stature, 3 had irregular menstrual cycles, 3 had undersized testicles, 5 showed an insufficient rise of growth hormone following the administration of growth-hormone-releasing hormone, 4 showed an insufficient rise in FSH after administration of gonadotropin-releasing hormone, 5 had manifest diabetes mellitus, 3 showed an impaired glucose tolerance, and 2 patients had subnormal serum levels of parathormone in combination with hypocalcaemia. One patient additionally had Klinefelter's syndrome with a kariotype 47, XXY and increased levels of FSH and LH, subnormal levels of testosterone and subnormal testicular volume. The occurrence of endocrine defects correlated with the duration of disease. The data demonstrate that endocrine abnormalities are frequently associated with mitochondrial myopathy, indicating that this multisystemic disease also involves various endocrine tissues.

Serum and saliva sex hormone levels in !Kung San men

Serum concentrations of testosterone (Tser), 5 alpha-dihydrotestosterone (DHT), estradiol 17 beta (E2), and free testosterone in saliva (Tsal) were determined by means of the radioimmunoassay method in 114 !Kung San men living in the Bushmanland district of Namibia. The healthy men (mean age 26.4 years) were asked about their dietary habits over the last two months and their acute alcohol intake during the 24 hours preceding the blood and saliva sampling. Although the sex hormone status of the !Kung lies within the range of normal men reported for Caucasoid samples, both Tser and Tsal exhibit relatively low concentrations in comparison to the great majority of published mean values. On the other hand, comparatively high DHT levels point to an elevated 5 alpha-reduction of testosterone to DHT in our sample. Estradiol concentrations show no deviation from normal values reported elsewhere for healthy young men. Different dietary habits of the !Kung lead to significant differences in their sex hormone status: both levels of Tsal and the androgen ratio Tsal/Tser decrease with increasing supplement of the traditional hunter-gatherer diet with domestic and Western food products. The amount of alcohol consumed during the day before the blood and saliva sampling shows a significant effect on the DHT metabolism, and the shorter the time after drinking, the greater decrease of DHT and DHT/E2 can be observed.

Gonadal endocrine dysfunction in patients with lung cancer: relation to responsiveness to chemotherapy, respiratory function and performance status

Male lung cancer patients with poor performance status [Eastern Cooperative Oncology Group (ECOG) index 3-4] have an endocrinological dysfunction as assessed by serum testosterone and sex hormone-binding globulin (SHBG) levels. Patients who respond to therapy regain normal free testosterone levels within 12 weeks post chemotherapy, whereas non-responders continue to exhibit subnormal levels. The perturbations of endocrinological variables in patients with lung cancer is not due to development of hypoxia, as patients with respiratory failure maintain a significantly lower testosterone level compared to cancer patients. The development of a deficiency in total testosterone concentrations in lung cancer patients is correlated to their performance status, and not to the presence of metastatic disease. The mechanisms responsible for the endocrinological dysfunction in patients with lung cancer remain unknown.

Effects of growth hormone administration on dehydroepiandrosterone sulphate, androstenedione, testosterone and cortisol metabolism during nutritional repletion

This study evaluated whether pharmacological doses of recombinant human growth hormone (hGH) influences androgen or cortisol metabolism during nutritional repletion following prolonged illness. Stable hospitalized adults (three males, seven female) receiving constant calorie and protein intake were studied. An initial control week was followed by a treatment period during which hGH (10 mg/day s.c.) was administered daily. Prior to hGH treatment, serum and 24-h urinary concentrations of dehydroepiandrosterone sulphate (DS) were below the normal range; serum androstenedione and testosterone concentrations were within the lower limit of normal. In contrast, serum cortisol (F) and 24-h urinary F excretion were normal. During hGH treatment, nitrogen balance became positive and plasma insulin-like growth factor I (IGF-I) concentrations rose five to seven-fold. However, serum DS, androstenedione, testosterone and F, and urinary F excretion did not change, while 24-h urinary DS excretion fell significantly. Growth hormone administration markedly stimulated protein anabolism but did not increase the low concentrations of circulating androgens or alter the disassociation between adrenal androgen and F release in stable hospitalized males and females. Thus, hGH does not appear to function as a cortical adrenal androgen stimulating hormone (CASH) or regulate adrenal cortisol or gonadal androgen release in this clinical setting.

Pathophysiology of sex hormone binding globulin (SHBG): relation to insulin

In humans, the plasma level of sex hormone binding globulin (SHBG) is regulated by several hormones. We have now accumulated evidence that SHBG is also intimately related to nutritional state. However, we do not yet know what specific signal, if any, may be the regulator of SHBG. There is a strong and negative correlation between fasting insulin level and SHBG in obese as in hyperandrogenic women. Under such circumstances, a high fasting insulin level, normal glycemia and a low SHBG level suggest insulin resistance in terms of glucose disposal but not in terms of SHBG inhibition. This is a rather complex situation. It is too early to judge the importance of IGF-I in the regulation of SHBG. But it may turn out that IGF-I is the main regulator of SHBG and that, by interaction with the IGF-I receptors, insulin carries on its inhibitory activity on SHBG.

Effects of a fat-containing meal on sex hormones in men

The effect of a fat-containing meal on plasma sex steroid concentrations was investigated in normal men. After an overnight fast on two separate occasions, subjects ingested a liquid meal containing either a nonnutritive sweetener (control), or isocaloric meals of mixed calorie sources with either high-fat content or mixed carbohydrate and protein with minimal fat. The order of the meals was alternated. Blood samples were collected at 15-minute intervals and pooled each hour. Sampling began at 7:00 AM and the test meal was ingested at 8:00 AM. Sex steroids, including estrone, estradiol, testosterone, and dihydrotestosterone (DHT), sex hormone-binding globulin (SHBG) capacity, free testosterone concentration, and luteinizing hormone (LH) were determined by either specific radioimmunoassay or dialysis. The fat-containing meal, but not the nonnutritive or mixed carbohydrate and protein meal, resulted in a significant (P less than .01) reduction in total and free testosterone. Estrogens and luteinizing hormone were unaffected by either meal. This is the first documentation, to our knowledge, of the acute effect of a fat-containing meal on sex steroid concentrations in blood. Our observations suggest that a fat-containing meal reduces testosterone concentrations without affecting luteinizing hormone. This might indicate that fatty acids modulate testosterone production by the testes.

Influence of diet on plasma steroids and sex hormone-binding globulin levels in adult men

Several experimental studies have suggested that diet can alter the production and metabolism of steroids in men. The purpose of this study was to determine the levels of unconjugated steroids and steroid glucuronides as well as sex hormone-binding globulin (SHBG) among normal adult men who were either omnivorous or vegetarians. The participants were white volunteers ranging from 25-35 years of age and the blood samples were taken between 0900 h and 1000 h and between 1600 h and 1700 h for two consecutive days. No significant statistical change was found in plasma dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, dihydrotestosterone and estradiol levels. Vegetarian group showed a higher levels of sex hormone-binding globulin (SHBG) while the free androgen index (FAI; calculated by the ratio testosterone/SHBG) was lower in this group. Although the concentrations of androsterone glucuronide were higher in vegetarian group, the vegetarians had a 25-50% lower level of androstane-3 alpha, 17 beta-diol glucuronide and androstane-3 beta,17 beta-diol glucuronide. Our data further indicate that both, androstane-3 alpha,17 beta-diol glucuronide and androstane-3 beta,17 beta-diol glucuronide concentrations are significantly correlated with SHBG levels and with the FAI values. The increases in androstane-3 alpha,17 beta-diol glucuronide and androstane-3 beta,17 beta-diol glucuronide levels in the omnivorous group are probably a consequence of the elevation of the FAI. Our data suggest that in a vegetarian group, less testosterone is available for androgenic action.

Relationships between serum testosterone, fasting insulin and lipoprotein levels among elderly men

We have previously reported the existence of an association between endogenous male sex hormone and lipoprotein levels in elderly men confined to a nursing home. In a further attempt to elucidate the significance of the association mentioned, we studied the relationship existing in that population between serum testosterone and fasting insulin levels, and between fasting insulin level and lipoprotein pattern. The data were analysed by means of stepwise multiple regression analyses. Serum testosterone and fasting insulin were found to be strongly correlated; this is consistent with the notion that androgen secretion affects directly circulating insulin level. But no independent relationship was demonstrable between fasting insulin and the three lipid-lipoprotein categories studied, namely total serum cholesterol, triglyceride and HDL-cholesterol, suggesting that in this particular population, the effect of male sex hormones upon lipoproteins is not mediated through insulin. Together, these various observations support the belief that androgen secretion affects significantly CAD risk factor levels in elderly men.

Influences of diet and nutrition on clinical pharmacokinetics

The human diet represents a complex and variable mixture of nutrients, many of which have the potential for altering the disposition of drugs. This review highlights progress from a number of laboratories illustrating nutrient influences on drug dispositions and actions. Emphasis is placed on nutritional effects on hepatic drug metabolism studied in humans. Data from animals have sometimes been difficult to extrapolate to humans, as illustrated by reports on the influences of starvation, dietary lipids, and ascorbic acid. From studies in healthy subjects it is now clear that a number of specific dietary factors can influence drug metabolism by the mixed function oxidase system and conjugating enzymes. These include dietary protein, cruciferous vegetables, charcoal-broiled beef containing polycyclic aromatic hydrocarbons, and methylxanthines. The effects of such dietary components have been demonstrated for only a limited number of drug substrates for these enzyme systems. Effects of food on bioavailability have been more widely studied, and depend greatly upon the type of drug. Malnutrition can be associated with variable but potentially important effects on the bioavailability, binding, hepatic metabolism, and renal clearance of drugs. In malnourished patients it is generally difficult to recognise the roles of individual nutrient deficiencies on drug disposition, and clinical predictors of altered pharmacokinetics for various drugs in such patients are not well defined. It is likely that many important interrelationships between nutrition and new or already marketed drugs remain to be recognised, and therefore warrant further research. Nutritional effects on drug metabolising enzymes also have implications for endogenous substances such as hormones and environmental toxins and carcinogens which are metabolised by the same or related enzyme systems, and for diseases likely to be related to the actions of such chemicals.