Endocrine Function In Man Research Articles

Longitudinal Evaluation of Reproductive Endocrine Function in Men with ACTH-Dependent Cushing Syndrome.

Hypogonadism may be caused by Cushing syndrome (CS) and may intensify its adverse consequences. To determine the frequency of male hypogonadism before and after curative surgery for CS, and its cause. Post-hoc analyses of prospective cohort studies. Clinical research center. Men with ACTH-dependent CS. Cohort 1 (C1) (n=8, age 32.5±12 y; studied 1985-1989); Cohort 2 (C2) (n=44, 42.7 ± 15.1 y; studied 1989-2021). C1: Every 20-minute blood sampling for 24h before and 1-40 months after surgical cure. Three subjects underwent GnRH stimulation tests pre- and post-surgery. C2: Hormone measurements at baseline and 6 and 12 months (M) post-cure. C1: LH, FSH, LH pulse frequency and LH response to GnRH. C2: LH, FSH, testosterone (T), free T, fT4, T3, TSH and UFC levels and frequency of hypogonadism pre- and post-surgery. C1: mean LH and LH pulse frequency increased after surgery (p < 0.05) without changes in LH pulse amplitude, mean FSH, or peak gonadotropin response to GnRH. C2: 82% had baseline hypogonadism (total T 205 ± 28 ng/dL). Thyroid hormone levels varied inversely with UFC and cortisol. LH, total and free T, and SHBG increased at 6M and 12M post surgery, but hypogonadism persisted in 51% at 6M and in 26% at 12M. Hypogonadism in men with CS is widely prevalent but reversible in ∼75% of patients one year after surgical cure and appears to be mediated through suppression of hypothalamic GnRH secretion, and modulated by thyroid hormones.

Effect of Antiepileptic Drugs on Sexual and Reproductive Endocrine Function in Men with Epilepsy (P6.259)

Effect of Antiepileptic Drugs on Sexual and Reproductive Endocrine Function in Men with Epilepsy (P6.259)

The -29G/A FSH receptor gene polymorphism is associated with higher FSH and LH levels in normozoospermic men.

The functional role of the FSHR promoter -29G/A polymorphism (rs1394205) in men is not clear. Some studies failed to find a relationship between the FSHR -29G/A and follicle-stimulating hormone (FSH) levels and did not associate the SNP with male infertility. Only one study showed that the FSHR -29 SNP modulates serum FSH levels in Baltic young male cohort. Because the SNP -29G/A has to be shown to have a strong effect on in vitro transcription activity of the FSHR promoter and the activation of FSHR is necessary for a normal FSH function, this study was undertaken to assess whether the FSHR -29G/A SNP modulates the gonadal endocrine function in men. A total of 200 men with alteration of conventional sperm parameters or normozoospermia (according to the parameters WHO 2010), were genotyped by TaqMan Assay. Hormone levels were measured by immunoassay, and sperm analysis was performed according to the World Health Organization criteria. A significant gradient of increasing FSH levels across the FSHR -29G/A genotypes was observed (p<0.01). Among normozoospermic men (n=110), those with FSHR -29A-allele carriers (GA+AA and AA) had higher serum FSH (p<0.01) and LH levels (p<0.05) and higher body mass index (BMI) (p<0.01) compared to men with the GG genotype. The carrier status of rs1394205 genotypes did not affect the other endocrine parameters neither in men with altered sperm parameters nor in normozoospermic men. The FSHR -29G/A polymorphism modulates FSH and, for the first time, LH serum levels and BMI in normozoospermic men. These findings underline the importance to pay close attention to the studies of genetic variations associated with clinical-endocrine parameters.

The Influence of Betaine Supplementation on Work Performance and Endocrine Function in Men

The Influence of Betaine Supplementation on Work Performance and Endocrine Function in Men

Vasectomy: a long-term study of its effects on testicular endocrine function in man.

Plasma testosterone, luteinizing hormone (L.H.) and follicle stimulating (F.S.H.) were measured before operation in 39 males, aged 26 to 53 years with 2 to 5 children, seeking vasectomy for contraceptive purposes. These measurements were repeated at 3 and 12 months after vasectomy. Levels of L.H. at 12 months were significantly higher than pre-vasectomy levels, suggesting some degree of decreased Leydig cell function. However, testosterone and F.S.H. levels were similar at the three sampling times. Continuing yearly measurements for at least 5 years are planned.

Reversible Effects of Antiepileptic Drugs on Reproductive Endocrine Function in Men and Women with Epilepsy—A Prospective Randomized Double‐Blind Withdrawal Study

Epilepsy, antiepileptic drugs (AEDs), and reproductive endocrine function have complex interactions. In this study, we wanted to investigate the effects of AEDs on reproductive endocrine function after withdrawal of AEDs and look for reversible endocrine effects. The study was prospective, randomized, and double-blinded. A total of 160 patients were included and randomized to withdrawal or not and 150 (80 females, 53%) patients went through the intervention and was included in the study for 12 months. Complete serum samples from before and 4 months after completed withdrawal/no withdrawal were obtained from 130 patients (63 females, 48%). The main finding was that reversible endocrine changes in sex steroid hormone levels could be observed in both sexes after withdrawal of AEDs. For CBZ, which was the drug used by the majority of the patients, withdrawal led to significant increases in serum testosterone concentrations and free androgen index (FAI) in both men (n = 19) and women (n = 19). Mean differences in change in FAI between the withdrawal group and nonwithdrawal group were in men 17.49 (CI 10.16-24.81, p <or= 0.001), and in women 1.61 (CI 0.62-2.61, p <or= 0.001). Our findings provide further evidence of the potentially negative effects of CBZ treatment on reproductive endocrine functions in men and women, but also show that some of these changes may be reversible, even after years on treatment.

Antiepileptic drugs alter reproductive endocrine hormones in men with epilepsy

Disturbances of reproductive endocrine hormones are more often found in men with epilepsy than in the general population. There is an ongoing debate whether this can be attributed to chronic use of antiepileptic drugs or to the epilepsy itself. The aim of the present study was to evaluate the degree of endocrine disturbances in men with epilepsy compared with healthy controls, and to investigate whether there was a drug-specific effect of valproate (VPA) or carbamazepine (CBZ). Men with epilepsy, 20-40 years old, having used either VPA (n = 16) or CBZ (n = 19) as monotherapy for >2 years were included and compared with age-matched controls. Men with epilepsy (VPA + CBZ) had significantly lower FSH values and higher C-peptide values compared with controls. Regarding possible drug-specific effects, the VPA treated patients had significantly higher dehydroepiandrosterone (DHEAS) levels and lower FSH and LH concentrations compared with the controls, whereas there were no differences in testosterone, testosterone/sexhormone-binding globulin (SHBG) ratio or androstenedione levels. Men on VPA also had significantly lower free carnitine/total carnitine, which may have implications for sperm motility, and also higher insulin and C-peptide concentrations. The CBZ treated patients had significantly lower testosterone/SHBG ratio than the controls. Compared with the CBZ treated patients, men on VPA had significantly higher DHEAS concentrations and lower levels of follicle stimulating hormone (FSH), luteinizing hormone (LH) as well as a lower free carnitine/total carnitine ratio. A marked age dependency was found in all three groups regarding several of the endocrine hormones. In conclusion, drug-specific endocrine effects of VPA and CBZ were found in men with epilepsy. Long-term VPA treatment leads to significant changes in DHEAS, FSH, LH, insulin, C-peptide and carnitine ratio. Long-term CBZ treatment leads to significant lower testosterone/SHBG ratio. A strict age matching were found to be of importance in the evaluation of endocrine function in men.

The effects of short-term resistance training on endocrine function in men and women.

This investigation examined hormonal adaptations to acute resistance exercise and determined whether training adaptations are observed within an 8-week period in untrained men and women. The protocol consisted of a 1-week pre-conditioning orientation phase followed by 8 weeks of heavy resistance training. Three lower-limb exercises for the quadriceps femoris muscle group (squat, leg press, knee extension) were performed twice a week (Monday and Friday) with every other Wednesday used for maximal dynamic 1 RM strength testing. Blood samples were obtained pre-exercise (Pre-Ex), immediately post-exercise (IP), and 5 min post-exercise (5-P) during the first week of training (T-1), after 6 weeks (T-2) and 8 weeks (T-3) of training to determine blood concentrations of whole-blood lactate (LAC), serum total testosterone (TT), sex-hormone binding globulin (SHBG), cortisol (CORT) and growth hormone (GH). Serum TT concentrations were significantly (P < or = 0.05) higher for men at all time points measured. Men did not demonstrate an increase due to exercise until T-2. An increase in pre-exercise concentrations of TT were observed both for men and women at T-2 and T-3. No differences were observed for CORT between men and women; increases in CORT above pre-exercise values were observed for men at all training phases and at T-2 and T-3 for women. A reduction in CORT concentrations at rest was observed both in men and women at T-3. Women demonstrated higher pre-exercise GH values than men at all training phases; no changes with training were observed for GH concentrations. Exercise-induced increases in GH above pre-exercise values were observed at all phases of training. Women demonstrated higher serum concentrations of SHBG at all time points. No exercise-induced increases were observed in men over the training period but women increased SHBG with exercise at T-3. SHBG concentrations in women were also significantly higher at T-2 and T-3 when compared to T-1 values. Increases in LAC concentrations due to exercise were observed both for men and women for all training phases but no significant differences were observed with training. These data illustrate that untrained individuals may exhibit early-phase endocrine adaptations during a resistance training program. These hormonal adaptations may influence and help to mediate other adaptations in the nervous system and muscle fibers, which have been shown to be very responsive in the early phase of strength adaptations with resistance training.

An Investigation into the Effects of Omeprazole on Renal Tubular Function and Endocrine Function in Man

Omeprazole is a substituted benzimidazole which inhibits gastric acid secretion by inhibition of parietal cell H+K+ATPase. It has previously been shown (1) that it is a powerful inhibitor of gastric acid secretion in man. In animal studies, antibodies raised against H+K+ATPase cross-reacted with thyroid and thymus tissue (2). AB Hässle have reported lowered tri-iodothyronine (T3) and raised thyroid stimulating hormone (TSH) levels in laboratory animals given omeprazole in very high doses (unpublished data). In this study, the effects of omeprazole on endocrine function in male subjects were investigated, and effects on renal tubular handling of acid and electrolytes examined.

ACTH 1–17 effects in psychogenic impotence

The purpose of this study was to investigate the effects of repeated administrations of ACTH 1-17 (Syncrodyn 1-17) on sexual and endocrine function in men with psychogenic impotence. Twenty adult impotent men from 21 to 48 years volunteered for this study; organic causes of erectile impotence were excluded in each subject. Ten subjects were treated with ACTH 1-17 (100 micrograms i.m. daily for 15 days during 6 consecutive months), whereas saline was injected in the control group (10 subjects) following the same protocol. Clinical and endocrine evaluation were performed before and at the end of treatment. Serum levels of LH, FSH, PRL, testosterone (T) and cortisol were measured by RIA methods. To investigate diurnal rhythms of T and cortisol, blood samples were taken at 0800 and at 1800. In ACTH 1-17-treated men a significant improvement in sexual function was shown when compared with the control group (p less than 0.05); moreover, both anxiety and fatigability were lowered by ACTH 1-17 administration. ACTH 1-17 did not affect basal levels of LH, FSH, PRL, T and cortisol, whereas the diurnal variation of T, which was absent before treatment in both treated and control group, was restored. No changes in clinical and endocrine parameters were shown after placebo injections. Our data emphasize that the chronopharmacological action of ACTH 1-17 may positively affect sexual function and circadian T rhythmicity in men with psychogenic impotence.

Large annual variation in photoperiodicity does not affect testicular endocrine function in man.

The purpose of the present study was to elucidate the possible influence of large differences in circannual photoperiodicity on human testicular activity. Serum testosterone was measured once a month in a group of 24 healthy young adult men for a period of 13 months in northern Finland, where the day length is 22 h in mid-summer and 3.5 h in mid-winter. The monthly levels of serum testosterone varied between 11.3 +/- 0.93 and 13.0 +/- 1.2 nmol/l (se, n = 24), with no significant differences between individual months. The amplitude of variations in serum testosterone was +/- 7% of the annual mean, which was less than in studies reported earlier from central Europe. Our negative findings suggest that the extreme circannual changes in the amount of day-light do not play an obvious role in the regulation of human testicular androgen production.

Effects of Enflurane Anaesthesia and Surgery on Endocrine Function in Man

Forty-five patients underwent enflurane anaesthesia and surgery. Anaesthesia alone evoked little change in the plasma concentrations of ACTH, cortisol or antidiuretic hormone (ADH), but there were significant increases during surgery. The plasma levels of aldosterone rose during anaesthesia alone, and a further increase was noted during surgery. Neither enflurane anaesthesia nor surgery significantly influenced plasma concentrations of renin activity and thyroxine. A significant decrease in the plasma triiodothyronine levels was detected during anaesthesia alone, and a further decrease was found during and following surgery. Enflurane anaesthesia did not affect the plasma level of luteinizing hormone (LH) in male subjects throughout surgery, but a significant decrease was detected in female patients on the first postoperative day. The plasma concentrations of testosterone decreased during anaesthesia alone and surgery, and a further decrease was noted on the first postoperative day.

An increase of plasma triiodothyronine concentration in man in a cold environment.

In an attempt to study an effect of cold on endocrine function in man, plasma thyroxine (T4), triiodothyronine (T3), TSH, and cortisol concentrations were studied in 24 healthy men who worked in a cold environment (4 to 6C) for 3 h for the culture of mushrooms and 56 healthy men who lived in cold environment in winter. For comparison, similar measurements were made on 47 university employees who lived in rooms with air-conditioning. In 24 adult men, acute exposure to cold for 3 h failed to affect plasma concentrations of T4, T3, and TSH. In 56 adult men, no significant difference was found in the concentrations of T4, TSH, and cortisol between summer and winter. However, plasma T3 concentration increased significantly in winter, suggesting seasonal variation of T3. In contrast, no such seasonal variation was found in 47 university employees who lived in rooms with air-conditioning.

318. Long-term effect of vasectomy on endocrine function in man

The long-term effect of one of the most extensively practiced antifertility procedures vasectomy on endocrine function in man has not been determined. We measured testosterone (T) and follicle stimulating hormone (FSH) by radioimmunoassay and testosterone binding (TB) by equilibrium dialysis in the plasma of 81 subjects from India of whom 12 were vasectomized for a period up to 5 years 20 for up to 4 years 21 for up to 3 years and 28 for a period between 1-2 years. The concentrations found in the different groups were for T 596 + or - 157 594 + or - 187 530 + or - 195 and 562 + or - 185 ng%; for FSH 14.63 + or - 5.74 13.74 + or - 6.09 15.74 + or - 8.14 and 17.44 + or - 9.85 mlU/ml; and for TB 93. 74 + or - 1.19 93.37 + or - 2.37 92.14 + or - 2.57 and 93.18 + or - 1.99% respectively. The mean values found in a control group of 16 normal males belonging to the same age group and the same geographical area were T = 582 + or - 158 ng% FSH = 15.09 + or - 8.74 M1U/ml and TB = 92.99 + or - 1.14%. Students t test between groups showed no significant difference between the control group and any of the other groups studied (p less than .001). These results show that vasectomy in man does not cause detectable abnormality in testosterone and FSH secretion and testosterone binding globulin synthesis even up to 5 years after operation. However since a large variation was observed in the parameters studied among the individuals within each group this investigation should be extended to study the concentration of these hormones in the same individuals before and after vasectomy. (FULL TEXT)

ANALOGIES BETWEEN URINARY 17-KETOSTEROIDS AND URINARY “ESTROIDS,” AS DETERMINED MICROCHEMICALLY*

SEVERAL years ago Callow and Callow (1) demonstrated that the microchemieal determination of 17-ketosteroids could yield valuable information regarding endocrine function in man and other animals. This finding has since been substantiated in many other laboratories (2–6). Nevertheless, considerable opposition to the procedure was raised originally on the grounds that: (a) the urinary 17-ketosteroids constitute a mixture; (b) their value is considerably higher than a biologically equivalent amount of androsterone; and (c) they vary with changes in both testicular and adrenal function. Similar objections can be raised with respect to urinary components related to estradiol. Degradation products of estradiol in urine Like testosterone, estradiol is converted within the human organism into degradation products of lower biological potency. The best known of such degradation compounds in the female are estrone and estriol (6). Smith and Smith (7) have also concentrated from human urine a substance which tentati...