Plasma testosterone levels following surgical stress in male patients

Testosterone variation in a semi-captive population of Asian elephants in Myanmar

Hormones are known to be involved in life-history trade-offs as systemic signals that establish functional links among traits and regulate key behavioural and physiological transitions between states in organisms. Although major functions of many steroid hormones such as testosterone are conserved among vertebrates, circulating concentrations vary widely both within and across species, and the degree to which observed hormone concentrations mediate life-history responses to environmental variation is less understood. In this study, we investigated how faecal testosterone metabolite (FTM) concentrations varied with extrinsic and intrinsic factors. To do so, we took advantage of a 6-year period of longitudinal sampling of FTM, indicators of stress and oxidative status in a semi-captive population of Asian elephants (n = 3163 samples from 173 individuals) in Myanmar. We determined how the variation in FTM is associated with age, sex, origin (captive-born or wild-caught), seasonality of the environment, individual stress level [measured by faecal glucocorticoid metabolite (FGM) and heterophil to lymphocyte ratio (H/L)] and oxidative status (reactive oxygen metabolite concentrations and superoxide dismutase activity). We reported that FTM increased with age from juvenile to adulthood for both sexes, with higher FTM concentrations in males than females. Moreover, elephants showed significantly higher FTM concentrations during the hot season and monsoon than in the cold season. However, for the physiological indicators, we found contrasting results. While FTM concentrations were strongly positively correlated with FGM concentrations, FTM concentrations were not related to H/L ratios. Finally, we found no relationship between FTM and the oxidative status of individuals. Our study provides new insights on the factors associated with variation in testosterone concentrations-a key hormone for reproduction and fitness of individuals-in Asian elephants living in their natural environment, which has relevance for effective conservation measures of this endangered species.

Hypogonadism and urologic surgeries: a narrative review

Background and Objective

Previous studies indicated that the treatment of male hypogonadism can be beneficial for intraoperative and postsurgical outcomes. In this study, we aimed to determine the impact of male hypogonadism on urologic surgeries. We provided an overview of the key studies in the field with the focus on the outcomes of urologic surgeries in hypogonadal men with/without testosterone replacement therapy (TRT).

Methods

We performed a literature review in PubMed and Google Scholar databases for the most relevant articles pertaining to the outlined topics without placing any limitations on publication years or study designs. We included full-text English articles published in peer reviewed journals between January 1970 and March 2022.

Key Content and Findings

Androgen deficiency is a common finding after major urologic surgeries. Although guidelines recommend against TRT in men with prostate carcinoma, recent investigations showed no association between TRT and disease progression and recurrence. Indeed, recent evidence suggested that low androgen levels could be related to high grade prostate carcinoma and increased risk of upgrading from low to high grade disease. Investigations on the application of TRT in benign prostatic hyperplasia (BPH) patients also revealed contrasting results. While some studies suggested higher rates of prostate-related events in men who received TRT, others showed that TRT could alleviate urinary symptoms in hypogonadal men with BPH. Decreased testosterone level is commonly seen in bladder cancer patients. The treatment of perioperative androgen deficiency can reduce postoperative morbidities and lower the risk of recurrence in these patients. Low testosterone levels are observed in approximately half of the men who undergo artificial urinary sphincter (AUS) placement and can increase the risk of complications.

Conclusions

The role of testosterone treatment in patients with urologic diseases such as prostate carcinoma and BPH is controversial. Further investigations are needed to determine the impact of hypogonadism and TRT on the outcomes of urologic surgeries in patients with androgen deficiency.

Neuropeptides as regulators of the hypothalamus-pituitary-gonadal (HPG) axis activity and their putative roles in stress-induced fertility disorders

Neuropeptides being regulators of the hypothalamus-pituitary-adrenal (HPA) axis activity, also affect the function of the hypothalamus-pituitary-gonadal (HPG) axis by regulating gonadotrophin-releasing hormone (GnRH) secretion from hypothalamic neurons. Here, we review the available data on how neuropeptides affect HPG axis activity directly or indirectly via their influence on the HPA axis. The putative role of neuropeptides in stress-induced infertility, such as polycystic ovary syndrome, is also described. This review discusses both well-known neuropeptides (i.e., kisspeptin, Kp; oxytocin, OT; arginine-vasopressin, AVP) and more recently discovered peptides (i.e., relaxin-3, RLN-3; nesfatin-1, NEFA; phoenixin, PNX; spexin, SPX). For the first time, we present an up-to-date review of all published data regarding interactions between the aforementioned neuropeptide systems. The reviewed literature suggest new pathophysiological mechanisms leading to fertility disturbances that are induced by stress.

Adrenal steroidogenesis following prenatal dexamethasone exposure in the spiny mouse

Antenatal stress disturbs the development of the fetal hypothalamic-pituitary-adrenal axis and adrenal steroidogenesis. We investigated the effect of brief maternal exposure to high glucocorticoids (dexamethasone (DEX)) at mid- and late-pregnancy on adrenal structure and production of steroids in spiny mouse. Pregnant spiny mice were treated for 60 h with 125 μg/kg DEX or saline s.c. by osmotic minipump at day 20 (0.5) or 30 (0.75) of gestation. Immunohistochemical expression of steroidogenic acute regulatory-protein (StAR), 3β-hydroxysteroid dehydrogenase (3βHSD), 17-hydroxylase,17-20lyase (P450C17), and cytochromeb5 (CYTB5) was determined in adrenals on postnatal (P) day 170±20. DHEA, testosterone, and cortisol were measured by RIA. Maternal DEX at 20 days significantly reduced the expression of STAR, P450C17 (CYP17A1), and CYTB5 in the adrenal zona reticularis (ZR) of adult offspring, with greater change in male vs female offspring (P<0.05). Plasma DHEA was decreased in male offspring from DEX-treated (6.84±1.24 ng/ml) vs saline-treated (13±0.06 ng/ml; P=0.01) dams, and the DHEA:cortisol ratio was lower in males (P<0.05). Testosterone levels increased in male offspring from DEX (266.03±50.75 pg/ml) vs saline (83.47±32.3 pg/ml, P<0.05)-treated dams. DEX treatment at 0.75 gestation had no significant effect on any parameters measured. This study shows that brief exposure to excess glucocorticoid has long-term impacts on the ZR and adrenal steroidogenesis, affecting the secretion of DHEA and testosterone in male offspring, an effect produced at 0.5 but not at 0.75 gestation. DHEA is important for brain development, and its suppression in adult life might contribute to the neurobehavioral pathologies that can arise after illness and stress during pregnancy.

Influence of paradoxical sleep deprivation and sleep recovery on testosterone level in rats of different ages

This study was performed to assess serum testosterone alterations induced by paradoxical sleep deprivation (PSD) and to verify their attenuation during sleep recovery (SR) based on different durations and ages. Wistar male rats aged 12 weeks for the younger group and 20 weeks for the elder group were randomly distributed into one of the following groups: a control group (cage and platform), 3-day SD, 5-day SD, 7-day SD, 1-day SR, 3-day SR and 5-day SR groups. For PSD, the modified multiple platform method was used to specifically limit rapid eye movement (REM) sleep. Differences in the testosterone and luteinizing hormone levels between the younger group and the elder group according to duration of PSD and SR recovery were analysed. Testosterone continued to fall during the sleep deprivation period in a time-dependent manner in both the younger (P=0.001, correlation coefficient r=-0.651) and elder groups (P=0.001, correlation coefficient r=-0.840). The elder group showed a significantly lower level of testosterone compared with the younger group after PSD. Upon SR after 3 days of PSD, the testosterone level continued to rise for 5 days after sleep recovery in the younger group (P=0.013), whereas testosterone concentrations failed to recover until day 5 in the elder group. PSD caused a more detrimental effect on serum testosterone in the elder group compared to the younger group with respect to decreases in luteinizing hormone (LH) levels. The replenishment of serum testosterone level was prohibited in the elder group suggesting that the effects of SD/SR may be age-dependent. The mechanism by which SD affects serum testosterone and how age may modify the process are still unclear.

Effect of short period vasectomy on FSH, LH, inhibin and testosterone secretions, and sperm motility in adult male rats

The present study was undertaken to clarify changes in secretions of FSH, LH, inhibin and testosterone, and sperm motility after bilateral vasectomy in adult male rats. Bilateral vasectomy was created surgically (treated group) and intact rats were used as control (control group). On days 3, 5, 7, 14, 30, 60, and 90 after surgery, plasma concentrations of FSH, LH, inhibin, and testosterone were measured by radioimmunoassay, and sperm motility characteristics were measured by computer-assisted sperm analysis (CASA). The results show that weights of epididymides significantly increased in vasectomized rats as compared to control rats. Histologically, damage to spermatogenesis was observed in vasectomized rats. Multinucleated giant cells were observed in the lumen of some seminiferous tubules, and there were degenerative spermatids in the epididymides of vasectomized rats. Plasma levels of LH, FSH, and testosterone only decreased on day 3 after vasectomy; however, plasma levels of ir-inhibin significantly increased on day 3 after vasectomy. In addition, the sperm motility parameters, straight-line velocity, curvilinear velocity, deviation of the sperm head from the mean trajectory and the maximum amplitude of lateral head displacement were decreased from day 60 after vasectomy. These results suggest that vasectomy reduces sperm motility starting from day 60 after vasectomy, and early bilateral vasectomy does not strongly affect the endocrine function of the testis, though it may result in damage to spermatogenesis in vasectomized rats.

Rapid, hierarchical modulation of vocal patterning by steroid hormones

Vocal control systems have been identified in all major groups of jawed vertebrates. Although steroid hormones are instrumental in the long-term development and maintenance of neural structures underlying vocalization, it is unknown whether steroids rapidly modulate the neural activity of vocal motor systems. The midshipman fish generates advertisement and agonistic calls that mainly differ in duration. A descending midbrain pathway activates a hindbrain-spinal vocal circuit that directly establishes the discharge frequency and duration of the rhythmic vocal motor volley. This vocal motor output, which can be monitored from occipital nerve roots, directly determines the rate and duration of contraction of a pair of sonic muscles and, in turn, the fundamental frequency and duration of vocalizations. Here, we demonstrate that the duration of the vocal motor volley, or fictive vocalization, is rapidly responsive to steroid hormones, including androgens, estrogens, and glucocorticoids. These responses are consistent, in part, with a nongenomic mechanism and are steroid specific at the receptor level, suggesting the possibility of multiple membrane-bound receptor populations. We also show, using intact and semi-intact preparations, that steroids hierarchically modulate fictive vocalizations; whereas the hindbrain-spinal region is both necessary and sufficient for rapid (within 5 min) effects on duration, descending midbrain input is necessary for maintenance (up to 120 min) of these effects. The conserved nature of vertebrate vocal motor systems suggests that the neuroendocrine principles outlined in this study may be a fundamental feature of all vocal vertebrates.

Influence of paradoxical sleep deprivation and cocaine on development of spontaneous penile reflexes in rats of different ages

Recent studies have established that paradoxical sleep deprivation (PSD) and cocaine administration induce genital reflexes (penile erection and ejaculation) in adult and old rats. To determine whether the same effects would induce spontaneous genital reflexes in rats of different ages (30-90 days old), we administered with cocaine (7 mg/kg) or saline to rats after a 4-day period of PSD, or at the equivalent time-point in control animals, and penile erection and ejaculation were then evaluated. In PSD rats administered cocaine, erection was observed from 30 days old to 90 days old, when both genital reflexes reached a peak. Animals submitted to PSD and saline injection showed erection from 60 to 90 days old. None of the control (saline and cocaine) groups of any age displayed these behaviors. The effects of PSD on steroid hormone levels showed that, although testosterone levels increased with age, PSD caused a marked decrease in testosterone at all ages evaluated. Progesterone and corticosterone levels were higher in PSD groups than in the respective control groups. These findings suggest that the interaction of PSD and cocaine probably enhances dopaminergic transmission in the brain and may accelerate the development of genital reflexes in male rats.

Does paradoxical sleep deprivation and cocaine induce penile erection and ejaculation in old rats?

A recent study has established that paradoxical sleep deprivation (PSD) and cocaine administration elicit genital reflexes (penile erection and ejaculation) in young rats. To discover whether the same effects occurred in old animals submitted to PSD, we administered cocaine (15 mg/kg) to young (3-month) and old (22-month) male rats after a 4-day period of PSD or at the equivalent time-point in control animals. We then evaluated erections and ejaculations. Sixty per cent of the old-PSD group displayed erection, although ejaculation was not observed. Genital reflexes were absent in young and old control groups. We found that PSD reduced testosterone and increased progesterone levels in both young and old PSD groups. In conclusion, our results suggest that although genital reflexes usually decrease with age, testosterone levels alone cannot account for these changes. The interaction of PSD and cocaine probably enhances dopamine transmission in the brain and may elicit penile erection in old rats.

Testosterone, cortisol and catecholamine responses to exercise stress and autonomic dysreflexia in elite quadriplegic athletes

Episodes of short high intensity exercise are associated with an increase in circulating total testosterone (T) in men. Mechanisms may include hemoconcentration, decreased metabolic clearance and/or increased synthesis. Beta-blockade abolishes the T response suggesting a direct beta-adrenergic effect on the testes. Some spinal cord injured (SCI) athletes deliberately induce autonomic dysreflexia (boosting) to enhance performance. Associated with this practice are elevated catecholamine (CA) levels and exaggerated responses to serum catecholamine levels. Since basal T levels are reported to be normal in the SCI male, the T response to acute high intensity exercise might be expected to be exaggerated by boosting and associated elevated CA levels. The acute exercise T response has not been examined in SCI men to date. To determine whether the increased CA values associated with boosting enhanced the exercise-induced T elevation we measured circulating levels of T, cortisol (C), norepinephrine (NE) and epinephrine (E) before and after maximal exertion and a simulated 7.5 km race with and without boosting in eight elite quadriplegic athletes. Maximal incremental exercise and a simulated 7.5 km race resulted in a rise in T similar to able bodied men under normal exercise conditions. Under boosted conditions the rise in T was eliminated while NE levels were significantly elevated above unboosted levels. The data may suggest an inhibitory role for CA on T production or release under conditions of extreme stress. Other possible mechanisms include C induced suppression, impaired gonadotropin stimulation of the Leydig cell and CA mediated alterations in gonadal blood supply.

Aggression in humans: what is its biological foundation?

Although human aggression is frequently inferred to parallel aggression based on testosterone in nonprimate mammals, there is little concrete support for this position. High- and low-aggression individuals do not consistently differ in serum testosterone. Aggression does not change at puberty when testosterone levels increase. Aggression does not increase in hypogonadal males (or females) when exogenous testosterone is administered to support sexual activity. Similarly, there are no reports that aggression increases in hirsute females even though testosterone levels may rise to 200% above normal. Conversely, castration or antiandrogen administration to human males is not associated with a consistent decrease in aggression. Finally, changes in human aggression associated with neuropathology are not consistent with current knowledge of the neural basis of testosterone-dependent aggression. In contrast, human aggression does have a substantial number of features in common with defensive aggression seen in nonprimate mammals. It is present at all age levels, is displayed by both males and females, is directed at both males and females, and is not dependent on seasonal changes in hormone levels or experiential events such as sexual activity. As would be expected from current knowledge of the neural system controlling defensive aggression, aggression in humans increases with tumors in the medial hypothalamus and septal region, and with seizure activity in the amygdala. It decreases with lesions in the amygdala. The inference that human aggression has its roots in the defensive aggression of nonprimate mammals is in general agreement with evidence on the consistency of human aggressiveness over age, with similarities in male and female aggressiveness in laboratory studies, and with observations that some neurological disturbances contribute to criminal violence. This evidence suggests that human aggression has its biological roots in the defensive aggression of nonprimate mammals and not in hormone-dependent aggression based on testosterone.

Effect of nasal instillation of female urine or vaginal exudate on testosterone secretion in isolated and anesthetized male rhesus monkeys (Macaca mulatta)

Two male adult rhesus monkeys were individually placed in cages with a pulling device in order to immobilize the animals for anesthesia. The room was temperature-controlled having a light/dark period of 12/12 hours. The animals were rapidly immobilized and immediately anesthetized with ketamine i. m. (10 mg/kg of body weight). They were bled four times at 15, 30, 45, and 60 mins after the ketamine injection, twice a week during 6 weeks. When necessary, maintenance doses of ketamine were administered. The levels of serum testosterone in experimental conditions (nasal instillation of female urine or a suspension of vaginal exudate) showed significant lower values with respect to those in control conditions (saline instillation). The control levels of testosterone tend to increase up to 60 mins. The testosterone from samples obtained in experimental conditions did not show such an increase, remaining similar during the sampling and similar to the 15 min control levels that could be considered as basal. These results seem to point out some chemical information from females capable of modifying the pattern of secretion of testosterone of the males in the above mentioned experimental conditions.

Cytosolic and nuclear androgen receptor activity in the cancer of the larynx

It is well known that the larynx is a target organ for androgens and the cancer of larynx is more frequent in male subjects. We have evaluated the androgen receptors (AR) in the cytosol (ACR) and in salt extractable (ANR) and salt resistant nuclear fraction (AMR) in a group of 24 male patients with cancer of the larynx surgically removed. In addition specimens obtained from the normal mucosa of the same subjects were analyzed. In 5 patients estrogen (ER) and progesterone (PgR) receptors were also assayed. In all subjects blood samples were taken before surgery for the assay of the following hormones: LH, FSH, estradiol, testosterone, dihydrotestosterone, delta 4-androstenedione, dehydroepiandrosterone sulfate, cortisol. The results observed showed that 18 out of 24 normal larynx mucosa specimens and 17 out of 24 larynx cancer specimens were positive for ACR or ANR or AMR. The 5 samples of normal and cancer tissues analyzed for ER and PgR were negative. In conclusion there is no significant correlation between AR positivity from one size, histology, degree of differentiation and invasivity of the cancer, age of patients and hormonal blood levels from the other. The high ANR and AMR positivity (normal hormonal translocation and binding on DNA acceptors) confirm that the normal and cancer larynx are target tissue for androgens and establish the hormone dependence of this cancer. Hormonal therapy could be envisaged as an alternative or a complementary therapy for this type of cancer at least in the cases in which the analysis of hormone receptors will prove to be positive.

Effects of caponization on body weight, atherosclerosis, and cardiovascular variables in hypertensive and hypotensive turkey lines

Effects of caponization and blood pressure selection on serum lipids, severity of atherosclerosis, body weight, hematocrit, and relative ventricular weight in hypertensive and hypotensive lines of turkeys were evaluated in two trials. At 8 weeks of age, half the turkeys from each line were caponized. Body weights, blood pressure, and blood samples were obtained from each treatment at 8, 20, and 30 weeks of age. A total of 56 and 72 birds were used in Trials 1 and 2, respectively. Birds were necropsied at 30 weeks of age. Hypertensive turkeys had significantly greater serum cholesterol and total lipid than hypotensive turkeys only at 30 weeks of age in Trial 1. Lower relative ventricular weights were observed in hypotensive turkeys within both trials. Hypertensive birds exhibited a more severe degree of atherosclerosis and higher relative heart weight than hypotensive turkeys. Caponization significantly increased total serum lipid only at 20 weeks of age in Trial 2. Average body weight of caponized turkeys was significantly lower (1.2) than the control turkeys at 30 weeks of age. Caponized turkeys exhibited lower relative ventricular weight in Trial 1 but not Trial 2 and an increase in blood pressure only in Trial 2. Caponization suppressed body weight, decreased hematocrit values, and had no significant effect upon plaque severity. The presence or absence of male sex hormones had virtually no effect on proposed atherogenic stimuli thereby suggesting another mechanism by which the female is afforded a higher degree of protection.

Alterations of neuroendocrine functions in spinal cord injury

A transverse myelopathy causes a marked dysfunction in the negative feedback of some of the hypothalamo-hypophyseal-target organ axes. Spinal cord injured (SCI) humans with lesions above T6 exhibit significantly lower serum LH and testosterone but not FSH. The parathyroid hormone-thyrocalcitonin regulation of bone metabolism is disturbed; the higher the lesion, the greater is the loss of mineral and matrix components of the bone. Further, the response to insulin induced hypoglycemia is blunted in SCI with high lesions, and their basal levels of norepinephrine, epinephrine, and cortisol are significantly lower than those of controls. Distension of the bladder or rectum, however, produces marked release of norepinephrine and concomitant increase in sympathetic activity. The results suggest impaired hypothalamo-hypophyseal-testicular, -adrenocortical, - adrenomedulary, -sympathetic axis dysfunction.

Effects of electroejaculation and ketamine-HCI on serum cortisol, progesterone, and testosterone in the male cat

The influence of manual restraint, ketamine-hydrochloride anesthesia and electroejaculation under anesthesia on circulating levels of cortisol, progesterone and testosterone was examined in male domestic cats. In the first experiment, cats were anesthetized with ketamine-HCI (17.5 mg/kg of body weight) and serially bled (controls) or serially bled and electroejaculated. These animals showed signs of recovering from anesthesia within 45 to 60 minutes of ketamine-HCI injection. Average serum cortisol concentrations increased (P less than 0.01) over the 84-minute sampling interval in both the electroejaculated and control groups. Cortisol levels reached their maximum concentration in the electrically stimulated males immediately postelectroejaculation (95.1 ng/ml) and were significantly greater (P less than 0.01) than in the controls (36.1 ng/ml) at a comparable time. Maximal mean cortisol concentrations in the control group (62.8 ng/ml) occurred 54 minutes after the first blood sample and occurred together with the onset of anesthesia recovery. Mean testosterone levels did not differ between electroejaculated and control cats, but did decrease (P less than 0.05) between the first and last blood sampling in both groups. In the second experiment, cats were bled on the same time schedule as in Experiment 1, but were bled while awake and manually restrained, or else during a deeper plane of anesthesia induced and maintained with higher doses of ketamine-HCI (initial dose, 23 mg/kg). Mean serum cortisol levels were greater (P less than 0.05) during manual restraint (range, 36.3-41.1 ng/ml) compared to deep anesthesia (range, 16.7-25.8 ng/ml), but did not change over the 84 minute sampling interval in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Testosterone, erythropoietin and anaemia in patients with disseminated bronchial cancer

In 21 newly diagnosed male patients with disseminated bronchial cancer, anaemia was associated with a reduced serum concentration of testosterone. Erythropoietin levels were increased in anaemic patients. The results suggest a normal erythropoietin response to anaemia in this condition. The reduced testosterone concentration is associated with normal levels of luteinizing hormone and its significance in the pathogenesis of the anaemia is uncertain.

Effect of maternal adrenocorticotropin injections on the differentiation of sexual behavior of the offspring

Male and female rats were prenatally exposed to high levels of corticosteroids, by treatment of their mothers with ACTH, during the last third of pregnancy. In the females, treatment increased the ano-genital distance at birth, but no effect on sexual differentiation could be detected in the adult animals: They had normal cyclic reproductive function and female lordotic sexual behavior. The prenatal treatment demasculinized the males, who showed decreased ability for complete male copulatory behavior. The demasculinizing effect of prenatal corticosteroids was, however, particularly pronounced in certain litters, while not affecting others at all.

Suppression of pituitary and testicular function in rats by a transplanted adrenocortical carcinoma

Snell adrenocortical carcinoma was transplanted into immature 4-week-old male rats, and the animals were sacrificed 3 weeks afterward for study of adenohypophyseal and testicular function. The weight of the tumour was 11 +/- 5 g; plasma corticosterone levels were elevated and plasma progesterone levels were massively increased compared to those in rats with no tumours. The weights of the adrenals, testes and androgen-dependent accessory reproductive glands were significantly decreased, as was the diameter of seminiferous tubules. The concentrations of testosterone, LH and FSH in the plasma were significantly reduced, whereas the levels of Prl and oestradiol were not affected. We suggest that steroid products of the transplanted tumour suppressed release of gonadotrophins from the pituitary, leading to a severe reduction of testosterone synthesis in the testes.

Suppressive effects of surgical stress on circulating androgens during and after prostatectomy

Changes in circulating testosterone (T) and dihydrotestosterone (DHT) levels were investigated 2 days before and 2, 7, 30 and 60 days after retropubic prostatectomy in 28 patients with benign prostatic hypertrophy. Following operation the concentrations of both steroids declined and reached minimal levels 2 days after surgery. One month post-operatively testosterone had recovered to its pre-operative value, whilst the recovery of dihydrotestosterone to its pre-operative level required a minimum period of 2 months. These data indicate the need for careful interpretation of any androgen measurement following surgery.

Endocrine profile of semen in subfertile males with varicocele

The semen levels of FSH, LH, estradiol, progesterone, and testosterone were estimated in normal fertile males and in patients with oligozoospermia and varicocele. The only significant difference between the mean values of the two groups was noted for semen LH. Patients with oligozoospermia and varicocele had lower level than the normal fertile males. As a function of prostatic infection, no significant difference was obtained.

Maternal stress alters plasma testosterone in fetal males

Titers of testosterone in plasma were determined by radioimmunoassay in male rat fetuses of stressed and control mothers on days 17, 18, 19, 21, and 23 (the day of birth) after conception. In fetuses of stressed mothers, testosterone concentrations were highest on day 17, declined on days 18 and 19, and then remained unchanged. In the control fetuses, testosterone increased from relatively low concentrations on day 17 to the highest amounts on days 18 and 19, and then declined. Thus, the persistence of feminine and impaired masculine sexual behavior in male offspring of stressed mothers could be due to the absence of a surge of circulating testosterone during days 18 and 19 after conception, a period postulated to be critical in the development of the central nervous system in the rat.

Effect of acute myocardial infarction on pituitary-testicular function

The effect of acute myocardial infarction on the secretions of LH, FSH and testosterone was studied in thirteen male patients. Plasma testosterone fell transiently on the fourth day after acute myocardial infarction. This was accompanied by a rise in LH on the same day which persisted for a week after infarction. Serum FSH showed no significant change. The data suggest that following the medical stress of myocardial infarction, testosterone concentration was suppressed resulting in a compensatory rise in LH.

Effect of surgical stress on pituitary-testicular function

The effect of surgical stress on the secretions of LH, FSH, testosterone (T) and oestradiol (E2) were studied in twelve male patients. During surgery LH rose significantly; post-operatively, LH fell but remained persistently elevated a week after operation. However, T and E2 fell progressively to a nadir on the second and fifth post-operative day respectively and remained suppressed. Serum FSH showed no significant change. Despite a post-operative decrease in sex hormone binding globulin (SHBG) binding capacity, non-SHBG bound T showed a decrease parallel to T. Multiple sampling studies showed that the secretions of LH were increased and that of T were decreased post-operatively. Following surgery, LH responses to LHRH were magnified, FSH and T responses showed no significant change when compared with the pre-operative responses. These data suggest that secretions of LH were increased during surgery. Following surgical stress, T and E2 concentrations were suppressed resulting in a compensatory elevation of LH concentrations.

Effect of prolonged exercise of serum testosterone levels in adult men

The purpose of the study was to: 1) identify the differences in serum testosterone levels among four groups of adult men differentiated on the basis of physical fitness and age, and 2) determine the effect of a four-month physical fitness programme consisting of running, calisthenics and recreational activities on the serum testosterone levels of the four groups. The groups were designated: high-fit, young aged about 32 (n = 7); high-fit, old aged about 52 (n = 7); low-fit, young (n = 7), and low-fit, old (n = 7). The subjects were selected and grouped according to physical fitness scores obtained using the regression equation of Ismail et al. Serum testosterone was determined by a radioimmunoassay method. The pre-test ANOVA revealed that the high-fit groups had a significantly (p less than .01) higher testosterone level (754.29 ng/100 ml) than the low-fit groups (548.07 ng/100 ml) and the high-fit, young group (925.01 ng/100 ml) was significantly (p less than .01) higher than the other three groups. Post-test values were adjusted using pre-test testosterone values as covariates. No significant differences among the groups were found indicating that the serum testosterone levels were the same regardless of different ages and fitness levels. The findings were discussed in light of physiological, biochemical and psychological factors.

Plasma testosterone levels in the male rhesus: influences of sexual and social stimuli

Four adult male rhesus monkeys were provided access individually to a group of receptive females. Each male assumed dominance and engaged in frequent copulations. Plasma testosterone levels increased two- to threefold during this period. Next, each male was subjected to sudden and decisive defeat by a large all-male group, and plasma testosterone fell following this experience. Two males were later reintroduced to the females, and plasma testosterone rose rapidly to the previous elevated levels.