The role of testosterone and other hormones in regulation of LH

Organizational and activational effects of testosterone on carrageenan-induced inflammatory pain and morphine analgesia

Men are typically reported to have higher pain thresholds than women. Gonadal hormones, particularly testosterone for males, may contribute to this effect. This study tested whether changes in the male hormonal milieu early or late in development alter the inflammatory pain induced by carrageenan (CARR, 3%, intraarticular). Male rats were either gonadectomized or sham gonadectomized neonatally. Once adults, the same rats underwent either sham surgery or gonadectomy, and received a testosterone or oil implant. After baseline testing two weeks later, animals were tested in response to mechanical and thermal stimulation following CARR-induced inflammation and injection of saline, 1 mg/kg, or 5 mg/kg morphine. Hormone alterations did not affect baseline responses, but CARR induced mechanical and thermal hyperalgesia in the injured limb. Gonadectomy in adult males injected with saline enhanced inflammation-induced sensitivity to mechanical but not thermal stimulation and the effect was reversed by testosterone. After inflammation, saline-treated males gonadectomized neonatally displayed lower mechanical threshold than control sham animals but this effect was not reversed by testosterone. Both doses of morphine increased mechanical and thermal thresholds. However, compared with the control group, 1 mg/kg morphine was equally effective in reducing mechanical hyperalgesia among groups of animals gonadectomized as adults, but less effective in males gonadectomized neonatally. The results suggest that in males: 1. the antihyperalgesic effect of testosterone (or its metabolites) in CARR-induced inflammation is established during development and maintained by circulating levels of testosterone in adulthood; 2. the nociception-related interaction between the opioid and gonadal systems influences the sensitivity to mechanical stimuli and is likely established during the period of sexual differentiation.

Influence of a transscrotal testosterone propionate administration on the serum level of selected hormones of the hypophyso-gonadal axis

This study was designed to examine the effect of a percutaneous scrotal administration of testosterone propionate (TP) on selected blood variables, in order to identify a reliable anti-doping probe liable to disclose the illicit use of testosterone. Twelve healthy adult males gave their informed consent for the study. Each morning (8:30) and for 10 consecutive days (D), a placebo (D:1,2,3,...8,9,10) or a testosterone propionate (200mg TP on D:... 4,5,6,7...) scrotal patch was installed. On D2 or D3 (placebo-treated) or D7 (TP-treated), venous blood samples were collected at 5 min intervals from 9:00 until 13:00. Serum LH, FSH, 17alpha-hydroxyprogesterone (17HP), testosterone (T), estradiol (E2) and SHBG contents were analysed by immunoassays. The high sampling frequency revealed that TP was associated with the complete abolition of serum LH pulses. Although statistically significant, TP treatment was not related to explicit changes in serum FSH, E2, T/E2 and T/SHBG. TP-induced effects were most significant on serum LH, T and 17HP and were most clearly illustrated by a bi-dimensional distribution plot of serum values of the latter variables. The expression of a combination of the latter parameters could eventually serve to detect testosterone misusers.

Androgen, estrogen, and progesterone receptor contents and serum hormone profiles in patients with benign hypertrophy and carcinoma of the prostate

Cytosolic and nuclear androgen, estrogen and progesterone receptor content was measured in the groups of 11 prostatic carcinoma (PCA) and 32 benign prostatic hypertrophy (BPH) samples. All BPH cases were positive for the cytosolic progesterone (PRc) and estrogen receptor (ERc), whereas only 85% of cases (23/27) contained the androgen receptor (ARc). Only those five patients who received estrogen treatment in the PCA group had detectable ARc. PRc was present in all of the PCA cases, whereas ERc could be detected in only 82% (9/11) of cases. Cytosolic contents of all three steroid receptors, however, were higher in the PCA group. The level of nuclear steroid receptors, although present in fewer cases in both groups, was higher than the cytoplasmic receptors. The serum profile of estradiol, cortisol, and prolactin was normal in both groups, whereas LH, FSH, and progesterone levels were higher than in normal adults. Serum testosterone level was within normal range in the BPH group, but it was significantly below normal (P less than 0.005) in PCA patients.

Effect of dihydrotestosterone on testicular and accessory gland function in male rhesus monkeys

Pituitary, testicular and accessory gland functions were assessed at intervals of 10-20 days in adult male rhesus monkeys given 10, 100 or 1000 micrograms dihydrotestosterone (DHT). Circulating levels of LH and testosterone were suppressed. Ejaculated spermatozoa showed morphological abnormalities and decrease in motility but sperm counts were unaffected. Seminal fructose was decreased in animals receiving DHT. Sexual behaviour was maintained in these animals.

Contrasting effects of subcutaneous pulsatile GnRH therapy in congenital adrenal hypoplasia and Kallmann's syndrome

A patient with congenital adrenal hypoplasia (AH) and hypogonadotrophic hypogonadism was treated with pulsatile subcutaneous GnRH therapy for 16 weeks in an attempt to induce puberty. No rise in serum LH or FSH concentrations occurred despite increasing doses of GnRH (2.8 micrograms/pulse-22.4 micrograms/pulse). In contrast a similar programme of therapy successfully initiated the biochemical changes of puberty in a patient with Kallmann's syndrome. Both patients before therapy had low basal serum LH and FSH concentrations with blunted LH and FSH responses to GnRH stimulation. After 1 week, serum LH and FSH rose into the normal adult range in the patient with Kallmann's syndrome. This study fails to confirm a previous report which suggested that intermittent low dose GnRH therapy may be of value in inducing puberty in AH. The reasons for the difference of pituitary responsiveness to GnRH in AH and Kallmann's syndrome are unclear at present.

Germ cell survival, differentiation, and epididymal transit kinetics in mouse testis subjected to high in vivo levels of testosterone enanthate

Androgenic steroids induce oligospermia at high doses, but few studies have assessed which cell types and spermatogenic processes are affected. Testis cell numbers and rate of differentiation were quantitatively evaluated in testosterone enanthate-treated male mice by use of histological and cell separation techniques. Reduction in the number of testicular germ cells in treated animals accounted for 40% of the total reduction of spermatozoa. Testis cells differentiated at a similar rate in treated and control animals. Spermatozoa moved to the cauda epididymidis a day earlier in testosterone-treated animals, and were lost from the cauda after only two days, rather than after the normal seven days. These results suggest that over half of the 98% reduction in sperm number in testosterone-treated animals occurred at the stage of passage through the cauda epididymidis.

Role of endogenous opiates in the expression of negative feedback actions of androgen and estrogen on pulsatile properties of luteinizing hormone secretion in man

We have tested the participation of endogenous opiate pathways in the negative feedback actions of gonadal steroids on pulsatile properties of luteinizing (LH) hormone release in normal men. To this end, sex steroid hormones were infused intravenously at dosages that under steady state conditions selectively suppressed either the frequency or the amplitude of the pulsatile LH signal. The properties of pulsatile LH secretion were assessed quantitatively by computerized analysis of LH series derived from serial blood sampling over 12 h of observation. When the pure (nonaromatizable) androgen, 5-alpha-dihydrotestosterone, was infused continuously for 108 h at the blood production rate of testosterone, we were able to achieve selective inhibition of LH pulse frequency akin to that observed in experimental animals after low-dosage androgen replacement. Under these conditions, serum concentrations of testosterone and estradiol-17 beta did not change significantly, but serum 5 alpha-dihydrotestosterone concentrations increased approximately two- to threefold, with a corresponding increase in levels of its major metabolite, 5 alpha-androstan-3 alpha, 17 beta-diol. In separate experiments, the infusion of estradiol-17 beta at its blood production rate over a 4.5-d interval selectively suppressed LH pulse amplitude without influencing LH pulse frequency. Estrogen infusion increased serum estradiol-17 beta levels approximately twofold without significantly altering blood androgen concentrations. We then used these schedules of selective androgen or estrogen infusion to investigate the participation of endogenous opiates in the individual inhibitory feedback actions of pure androgen or estrogen on pulsatile LH release by administering a potent and specific opiate-receptor antagonist, naltrexone, during the infusions. Our observations indicate that, despite the continuous infusion of a dosage of 5 alpha-dihydrotestosterone that significantly suppresses LH pulse frequency, co-administration of an opiate-receptor antagonist effectively reinstates LH pulse frequency to control levels. Moreover, during the infusion of a suppressive dose of estradiol-17 beta, opiate receptor blockade significantly augments LH pulse frequency and increases LH peak amplitude to control levels. Thus, the present studies in normal men demonstrate for the first time that the selective inhibitory action of a pure androgen on LH pulse frequency is effectively antagonized by opiate-receptor blockade. This pivotal observation indicates that opiatergic and androgen-dependent mechanisms specifically and coordinately control the hypothalamic pulse generator for gonadotropin-releasing hormone (GnRH)

Effects of delta 9-THC and castration on behavior and plasma hormone levels in male mice

Gonadectomy resulted in a rapid increase in plasma luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels, but had no consistent effects on plasma prolactin (PRL) and growth hormone (GH) levels. In castrated males, oral administration of THC (50 mg/kg) significantly increased plasma LH levels within hours following surgery and again from 3 to several weeks post-castration, while THC treatment decreased LH levels between 1 day and 2 weeks postcastration. Administration of THC to 12-hour sham castrates significantly increased plasma LH levels. Plasma FSH, PRL and GH levels were either reduced or unchanged by THC. Administration of THC significantly reduced levels of gonadotropins, PRL and GH in intact males. In additional studies, we examined the influence of THC on the negative feedback response of the anterior pituitary to gonadal steroids. In testosterone propionate (TP)-treated castrated males, concomitant administration of THC increased plasma testosterone (T) and LH at 20 min, while plasma FSH levels were elevated after 60 min. In contrast, in intact TP-treated mice, concomitant THC exposure reduced plasma T levels except at 60 min, when plasma LH levels were significantly increased. Testosterone replacement failed to restore copulatory behavior in castrated mice given a single dose (50 mg/kg) of THC. In fact, acute THC administration to these TP-treated castrates resulted in marked sedation, which was not observed in intact mice given the same dose of THC in an earlier study. The present findings indicate that the effects of acute THC treatment on pituitary gonadotropin release is dependent upon the time after castration. Furthermore, THC administration can suppress copulatory behavior even in animals whose peripheral T levels have been maintained. Effects of THC on plasma androgen levels in animals injected with TP suggest that THC can alter the metabolism or target tissue response to gonadal steroids.