Testicular Response Research Articles

The testicular immune response in infectious and autoimmune orchitis

The testicular immune response in infectious and autoimmune orchitis

Congenital Idiopathic Hypogonadotropic Hypogonadism: Evidence of Defects in the Hypothalamus, Pituitary, and Testes

Idiopathic hypogonadotropic hypogonadism (IHH) with normal smell (normosmic IHH) or anosmia (Kallmann syndrome) is associated with defects in the production or action of GnRH. Accordingly, most IHH patients respond to physiological pulsatile GnRH replacement by normalizing serum LH, FSH, and testosterone (T) levels and achieving gametogenesis; some patients, however, show atypical responses. Interestingly, several IHH-associated genes are expressed in multiple compartments of the hypothalamic-pituitary-gonadal axis. The aim of the study was to investigate whether the clinical, biochemical, or genetic characteristics of IHH men with atypical responses to GnRH indicate alternative or additional defects in the hypothalamic-pituitary-gonadal axis. We studied 90 IHH men undergoing long-term pulsatile GnRH treatment over 30 yr. We conducted a retrospective study of response to GnRH at a Clinical Research Center. Physiological regimens of pulsatile s.c. GnRH were administered for at least 12 months. Dose-response studies using i.v. GnRH pulses assessed the pituitary LH response. We measured serum T, LH, FSH, and inhibin B levels, sperm in ejaculate, and determined the sequence of IHH-associated genes. Twenty-six percent of subjects displayed atypical responses to GnRH: 1) 10 remained hypogonadotropic and hypogonadal, demonstrating pituitary and testicular defects; 2) eight achieved spermatogenesis and normal T but only with hypergonadotropism, indicating impaired testicular responsiveness to gonadotropins; and 3) five remained azoospermic despite achieving adult testicular volumes and normal hormonal profiles, suggesting primary defects in spermatogenesis. Mutations were identified only in KAL1 across groups. In addition to hypothalamic GnRH deficiency, IHH men can have primary pituitary and/or testicular defects, which are unmasked by GnRH replacement.

Developmental changes in the pituitary-gonadal-axis in male Mongolian gerbils from birth to adulthood.

The development of the pituitary-gonadal-axis and of body and organ weights was investigated in male Mongolian gerbils. During the neonatal period from birth to 7 days of age testicular activity was high but decreased to low prepubertal levels from 7 to 28 days of age. The pubertal period occurred from 1 to 3 months of age and was characterized by an intense rise in serum testosterone concentrations and in testicular testosterone production in-vitro. At 2.5 months of age accessory organs achieved their adult weight, at the same time as both, serum testosterone concentration and in-vitro testosterone production, reached their respective maximum levels. From 4 until 24 months of age no further relevant changes occurred in the pituitary-gonadal-axis. This study demonstrates that the testicular responsiveness is an important factor for the pubertal increase of testosterone during sexual maturation of male Mongolian gerbils.

Pituitary and testicular response to luteinizing hormone releasing hormone in normal and sulpiride-induced hyperprolactinaemic men.

Pituitary and testicular response to an intravenous infusion of 480 micrograms luteinizing hormone releasing hormone (LHRH) for 8 hours (1 microgram/min) was investigated in 8 male volunteers in normal and hyperprolactinaemic state. Eight normal men were given 150 mg of sulpiride daily for 14 days. Serum prolactin (PRL) levels were elevated significantly, but basal serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) did not change following daily oral administration of sulpiride in 8 normal men. Eight men showed biphasic LH response to LHRH infusion in both normal and hyperprolactinaemic state, and there was a rather exaggerated response in serum LH concentration in hyperprolactinaemic state. Serum FSH response to LHRH was similar in normal and hyperprolactinaemic state. Although slight increase in serum testosterone concentration was observed during LHRH infusion in normal and hyperprolactinaemic state, the statistical difference was not significant. The result of the present study suggests that the function of the hypothalamic-pituitary-testicular axis, as measured by serum gonadotrophin and testosterone responses, is well reserved.

Immunologic and testicular response in guinea pigs after unilateral traumatic orchitis.

An acute and intense trauma was inflicted in one of the testes of adult guinea pigs. The immunological response and histological changes developed both in the injured and contralateral glands were studied at different intervals of time. It was observed: 1) Necrotic seminiferous tubules and a granulomatous cell reaction were seen in the injured gonad at 15 days. This was followed by a reduction of the mononuclear cell infiltration at 48 days. Finally a fibrotic tissue replaced the damaged areas at around 100 days. 2) Foci showing the classical picture of immunologic orchitis appeared in the contralateral gland at 15 and 48 days. Less frequent lesions were detected in the final period of the experiment. 3) These lesions were accompanied by cellular immunity detectable by the macrophage migration inhibition test at 15 and 48 days. With the exception of cytophilic activity also detected in same periods, no antibodies of hemagglutinating and sperm-agglutinating types could be found.

In vitro Studies on Histochemical Localization of Testicular δ5 -3β-Hydroxysteroid Dehydrogenase Activity from Indomethacin Pretreated Rats - Effect of Prostaglandins and Luteinizing Hormone

In vitro studies on the effect of LH and prostaglandins on delta5 3beta-hydroxysteroid dehydrogenase activity using indomethacin pre-treated testis as the experimental model, revealed a greater stimulation of the enzyme activity when the incubation medium contained LH and PGE2 both at a concentration of 1 microgram/ml in comparison to the effect produced by 1 microgram LH/ml alone, but the augmentory effect of PGE2 on testicular response to LH was not evidenced as the LH: PGE2 ratio became 1 : 10. Neither PGE2 nor PGF2A produced any stimulation of the enzyme activity at concentrations of 1, 10, or 20 microgram/ml in the incubating medium. PGF2A at concentrations of 1 or 10 microgram/ml did not appear to interfere with LH action on this steroidogenic enzyme. On the contrary, prostaglandins, both PGE2 and PGF2A, at concentrations of 20 microgram/ml, antagonized LH action over testicular delta5-3beta-hydroxysteroid dehydrogenase activity. On the basis of these findings, it appears that prostaglandin E2 in some way, is necessary for manifestation of the steroidogenic action of LH in testis.

Pituitary and Testicular Response to LH-RH and to a Long-Acting Analogue (D-Leu-6-LH-RH-Ethylamide)

The LH, FSH and testosterone response to 50 microgram i.v. LH-RH and to 2.5, 5.0, 10.0, and 20.0 microgram i.m. D-Leu-6-LH-RH-ethylamide was studied in 6 subjects with normogonadotrophic, idiopathic oligozoospermia. All injections were given between 8:00 and 9:00 a.m. at weekly intervals. Blood samples were collected before and 30 and 45 minutes after injection of LH-RH, and before and 2, 4, 6, 12, and 24 hours after D-Leu-6-LH-RH-ethylamide injections. Serum levels of LH, FSH, and testosterone were measured by triplicate by R.I.A. LH and FSH responses to LH-RH showed peak values at 30 minutes, whereas following injections of D-Leu-6-LH-RH-ethylamide, maximal values were recorded between 4 and 6 hours and were higher than those obtained with LH-RH. A significant rise of serum testosterone levels was observed after all stimuli, with peak values 45 minutes after LH-RH and 4 to 6 hours after D-Leu-6-Lh-RH-ethylamide injections. The testosterone levels obtained following LH-RH and different doses of the analogue did not differ significantly from one another. The same sequence of maximal LH and FSH values was obtained after injections of LH-RH and of D-Leu-6-LH-RH-ethylamide, particularly at doses of 10.0 and 20.0 microgram. This suggests that the gonadotrophin response to these agents would be a true reflection of the individual mode of pituitary response.

Effect of an antiestrogen on the testicular response to acute and chronic administration of hCG in normal and hypogonadotropic hypogonadic men: Tamoxifen and testicular response to hCG*

The effect of the antiestrogen tamoxifen (Tx) on the acute and chronic hCG administration was evaluated in patients with hypogonadotropic hypogonadism (HH) and in normal men. An hCG test (5000 IU hCG) was performed before, after two months of hCG administration (2000 IU hCG three times weekly) and after two months of hCG + Tx (2000 IU hCG three times weekly plus 20 mg/day of tamoxifen). Blood samples were obtained before and following 24 and 72 h of every test to determine T, E, 17OHP and SHBG. T increased only in HH with both treatments (X +/- SEM: Basal: 97.9 +/- 19.7; hCG: 237.7 +/- 43.2; hCG +/- Tx: 204.7 +/- 10.7 ng/100 ml). 17OHP rose with hCG alone, but not with hCG + Tx in both groups. E, SHBG and 17OHP/T ratio did not change after treatments. hCG tests: E increased 24 h following hCG administration in every test. The ratio 17OHP/T rose at 24 h in the first and second test but in the third test it did not change. These results support the role of E in the acute hCG-induced Leydig cell desensitization. However, the association of Tx does not improve T serum levels, suggesting that E might not be the unique factor involved in the mechanisms for testicular desensitization.

178. RAT TESTICULAR MACROPHAGES EXHIBIT AN 'ALTERNATIVELY ACTIVATED' RESPONSE TO LIPOPOLYSACCHARIDE (LPS), INTERFERON-Γ (IFNΓ) AND INTERLEUKIN-4 (IL-4), CONSISTENT WITH IMMUNE PRIVILEGE

Testicular macrophages (TMs) are implicated both in the response of the testis to invading pathogens and supporting the immunosuppressive environment that protects developing germ cells (immunoprivilege). Macrophages are classified into two general phenotypes: “classically activated” (M1), which undergo inflammatory responses to LPS and IFNg, and “alternatively activated” (M2), defined by anti-inflammatory activity and regulated by IL-4. Our aim was to establish whether TMs have an M2 phenotype, consistent with immunoprivilege. Rat TMs and bone marrow-derived macrophages (BMMs) were isolated from adult rats, and cultured with LPS, IFNg and/or IL-4 for 2-3h. mRNA expression was measured by real-time RT-PCR and protein production was measured by ELISAs. Compared with BMMs, TMs stimulated with LPS and IFNg, either individually or in combination, expressed low levels of pro-inflammatory cytokines, such as IL-1β, IL-1α and tumour necrosis factor-α, intermediate levels of IL-6, but much greater levels (8-fold) of the anti-inflammatory cytokine, IL-10. TMs also displayed elevated constitutive expression of IL-10 and responded to IL-4, unlike BMMs. However, TMs expressed relatively low levels of another immunoregulatory cytokine, transforming growth factor-β1. After FACS-sorting of TMs using an antibody to CD163, a surface marker associated with M1-M2 progression, CD163+ TMs produced high levels of IL-10 constitutively and after stimulation, whereas CD163- cells produced little or no IL-10. Unexpectedly, both CD163- and CD163+ TMs expressed similar levels of most pro-inflammatory genes. These data indicate polarisation of TMs towards the M2 phenotype, characterised by production of IL-10 and responsiveness to IL-4, although the polarised TMs continue to express pro-inflammatory cytokines, albeit at significantly lower levels than other macrophages. The M2 phenotype is consistent with a role in testicular immunosuppression, but may also contribute to fibrosis, which is associated with testicular responses to vasectomy, cryptorchisism and infertility.

Food deprivation during photosensitive and photorefractory life-history stages affects the reproductive cycle in the migratory Red-headed Bunting(Emberiza bruniceps)

In a seasonally breeding bird species, food deprivation affects reproduction. A key question is whether food shortage at any time in the year will affect reproduction even though the food supply subsequently becomes adequate. A prediction would be that a food supply that is of shorter duration than that optimally required during a life-history stage will have consequential effects on the succeeding life-history stages. Two experiments investigated this in gonadally regressed migratory Red-headed Bunting (Emberiza bruniceps) at two life-history stages: photosensitive and photorefractory. Experiment 1 employed two groups of photosensitive birds, and experiment 2 employed two groups of photorefractory birds. In both the experiments, birds were exposed for 8 weeks to a neutral day length at dim light intensity (12 h light: 12 h darkness, 12L:12D; L= approximately 5 lux, D=0 lux) with restricted feeding regimes (6 h food present: 18 h food absent, P:A 6:18 or P:A 12:12) and subsequently maintained for another 13 weeks at a highly stimulatory day length (16L:8D; L=400 lux; D=0 lux) with food ad libitum. We report that the pretreatment with restricted food cycles influenced the subsequent photoperiodic induction of reproductive (testis growth and molt) but not of metabolic (body fattening and mass gain) functions. The testicular response cycle under 16L:8D had a significantly lower amplitude in birds pretreated with P:A 6:18 than with P:A 12:12. Similarly, the recovery of photosensitivity was slower in photorefractory birds pretreated with P:A 6:18 than with P:A 12:12 food cycles. Overall, our findings show for the first time in a seasonally breeding vertebrate species that food deprivation during non-breeding periods of the annual cycle can affect reproductive functions later in the year.

Lindane induces testicular apoptosis in adult Wistar rats through the involvement of Fas–FasL and mitochondria-dependent pathways

Lindane, an organochlorine pesticide, is known to impair testicular functions and fertility. To elucidate the mechanism(s) underpinning the gonadal effects of lindane, we sought to investigate the levels of apoptosis-related proteins, namely cytochrome c, caspase-3 and-9, Fas and FasL in the testis of adult rats. Furthermore, the study aims to delineate whether nuclear factor kappa B (NF-κB) is involved in meditating the testicular effects of lindane. Animals were administered with a single dose of lindane (5 mg/kg body weight) and sacrificed at specific post-treatment intervals (0, 3, 6, 12, 24 and 72 h). Significant elevations in the levels of cytosolic cytochrome c with a parallel increase in pro-caspase-9 were observed as early as 6 h following exposure. Time-dependent elevations in the levels of Fas, FasL and caspase-3 were observed. Immunofluorescence studies revealed increased colocalization of Fas and caspase-3 in peritubular germ cells. FasL levels were increased in Sertoli and peritubular germ cells. The cytoplasmic levels of NF-κB p65 decreased from 3 h following exposure with a maximal decline at 12 and 24 h. Changes in the localization of NF-κB were observed with maximal nuclear translocation in germ cells at 12 and 24 h. Terminal deoxynucleotidyl transferase-mediated dUTP nickend-labeling (TUNEL) assay revealed a time-dependent increase in the number of apoptotic cells. Taken together, the data illustrate induction of testicular apoptosis in adult rats following exposure to a single dose of lindane. Early activation of NF-κB in contrast to late increase in Fas expression suggests a pro-apoptotic role of NF-κB in testicular response to lindane.

Mouse Heat-Shock Factor 1 (HSF1) Is Involved in Testicular Response to Genotoxic Stress Induced by Doxorubicin1

Heat-shock factor 1 (HSF1) protects cells and organisms against various types of stress, either by triggering a complex response that promotes cell survival or by triggering cell death when stress-induced alterations cannot be rescued. Although this dual role of HSF1 was observed in spermatogenesis exposed to heat shock or proteotoxic stress, HSF1 was also reported to contribute to cell resistance against genotoxic stress, such as that caused by doxorubicin, an anticancer drug in common clinical use. To better understand the stress/cell-dependent functions of HSF1, we used wild-type and Hsf1(tm1Ijb)/Hsf1(tm1Ijb) males to determine the role of HSF1 in the genotoxic stress response elicited in spermatogenic cells. Within 2 days after a single intraperitoneal injection of doxorubicin (DOXO; 5 mg/kg), proliferation of Hsf1+/+ but not Hsf1-/- spermatogenic cells was significantly reduced, whereas cell death was increased in mitotic germ cells and metaphase I spermatocytes. By 21 days, meiotic cells were depleted in all treated Hsf1+/+ testes but not in Hsf1-/- ones. Nevertheless, after 3 mo, spermatogenesis showed better signs of recovery in Hsf1+/+ than in Hsf1-/- males. Taken together, these data indicate that acute response to genotoxic stress in the testis involves HSF1-dependent mechanisms that induce apoptotic cell death in a TRP53-independent manner, but also intervene on a longer term to restore seminiferous tubules.

Mechanism by Which Uropathogenic Bacteria Escape the Testicular Immune Response.

Mechanism by Which Uropathogenic Bacteria Escape the Testicular Immune Response.

Single exposure to low dose of lindane causes transient decrease in testicular steroidogenesis in adult male Wistar rats

Substantial evidence has piled up portending the adverse effects of environmental toxicants on male reproduction. Lindane, an organochlorine pesticide, has been reported to perturb testicular functions and hence fertility. To get more insight into the mechanism(s) involved in gonadal effect(s) of lindane, we sought to investigate whether treatment with lindane at a low dose would alter the levels of steroidogenic acute regulatory protein (StAR), androgen binding protein (ABP) and activities of steroidogenic enzymes (3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase) in adult rat. Furthermore, the levels of H 2O 2 were monitored to delineate the possible role of H 2O 2 in mediating the testicular effects of lindane. Animals used for experimentation were divided into six groups and four animals were maintained in each group. Animals were administered with a single dose of lindane (5 mg/kg body weight) and terminated at specific post-treatment intervals (0 h, 3 h, 6 h, 12 h, 24 h and 72 h) to analyze the early testicular response. Administration of lindane resulted in a sequential reduction in the levels of StAR and the activities of steroidogenic enzymes with a parallel increase in the levels of H 2O 2. These changes elicited by lindane were significant at 12 h and 24 h post-treatment. In case of ABP, a significant decline in the level was found at 12 h after treatment. These findings demonstrate transient inhibitory effects of lindane on testicular steroidogenesis and the possible role of H 2O 2 in mediating these effects.

Short photoperiod and testosterone-induced modification of GnRH release from the hypothalamus of Peromyscus maniculatus

Seasonally breeding animals undergo numerous physiological changes in response to changes in the length of the photoperiod. In most warm-weather breeding rodents, these changes result in reproductive quiescence during short photoperiods. It has been hypothesized that this change is mediated by changes in the activity of gonadotropin-releasing (GnRH) hormone neurons of the hypothalamus. This study was designed to test whether there are changes in the releasable pool of GnRH in the hypothalamus in response to changes in photoperiod, the presence of gonadal steroids, or the responsiveness of the individual animal to photoperiodic changes. Male deer mice (Peromyscus maniculatus) were maintained on long or short day photoperiod and either left intact, castrated, or castrated with testosterone replacement. KCl-evoked GnRH release was measured from hypothalamic explants from each animal and compared between long and short days, between castrated, intact, and castrated with testosterone replacement animals, and between animals that did or did not show gonadal regression in response to short day treatment. There was a significant decline in evoked release of GnRH in short day housed animals when comparing photoperiod responsive mice to nonresponsive mice. In addition, both reproductively nonresponsive and long day-housed mice release less GnRH following castration than their intact counterparts. When castrated long day-housed mice were provided with long day levels of testosterone, evoked GnRH release was restored to intact levels. Taken together, the results of this study suggest that variation in testicular response to short days is most likely due to differences in the release of GnRH from the hypothalamus.

Short‐term fasting leads to inhibition of responsiveness to LH‐stimulated testosterone secretion in the adult male bonnet monkey

A variety of stressors including fasting profoundly inhibit reproductive function in mammals. Although the effect of short-term fasting on gonadotropic axis is well established, the direct effects of fasting on gonads have not been reported. The objectives of the present experiments were to examine the effect of short-term fasting on circulating luteinizing hormone (LH) and testosterone (T) secretion, and to determine the responsiveness of testis to exogenous recombinant human (rh) LH treatment in male bonnet monkeys. In addition, an experiment was carried out to examine whether brief inhibition of endogenous LH secretion causes alteration in testicular responsiveness. Adult male monkeys were fasted for 1 day for examining the circulating endocrine hormone concentrations and challenged with rhLH injection 1 day after fasting. Food withdrawal for 1 day resulted in significant (P<0.05) decrease in LH, T and increase in cortisol concentrations. Surprisingly, T secretion in response to direct stimulation of Leydig cells by LH was not observed in fasted monkeys. In fed monkeys, treatment with Antide (a specific gonadotropin releasing hormone receptor antagonist to inhibit pituitary LH secretion) for 1 day did not compromise T secretion stimulated by rhLH, suggesting that loss of responsiveness of testis to exogenous LH treatment in fasted monkeys was not because of interruption in pituitary LH stimulation of the testis. The results indicate that short-term fasting in adult male monkeys cause inhibition of LH and T secretion, and inhibition of responsiveness of testis to LH stimulation.

Melatonin in the Regulation of Annual Testicular Events in Carp Catla catla: Evidence from the Studies on the Effects of Exogenous Melatonin, Continuous Light, and Continuous Darkness

The physiological significance of melatonin in the regulation of annual testicular events in a major carp Catla catla was evaluated through studies on the effects of graded dose (25, 50, or 100 µg/100 g body wt.) of melatonin exogenously administered for different durations (1, 15, or 30 days) and manipulation of the endogenous melatonin system by exposing the fish to constant darkness (DD) or constant light (LL) for 30 days. An identical experimental schedule was followed during the preparatory (February–March), pre‐spawning (April–May), spawning (July–August), and post‐spawning (September–October) phases of the annual cycle. Irrespective of the reproductive status of the carp, LL suppressed while DD increased the mid‐day and mid‐night values of melatonin compared to respective controls. Influences of exogenous melatonin varied in relation to the dose and duration of treatment and the reproductive status of the carp. However, testicular response to exogenous melatonin (at 100 µg, for 30 days) and DD in each reproductive phase was almost identical. Notably, precocious testicular maturation occurred in both DD and melatonin‐injected fish during the preparatory phase and in LL carps during the pre‐spawning phase. In contrast, testicular functions in both the melatonin‐treated and DD fish were inhibited during the pre–spawning and spawning phases, while the testes did not respond to any treatment during the post‐spawning phase. In conclusion, this study provided the first experimental evidence that melatonin plays a significant role in the regulation of annual testicular events in a sub‐tropical surface‐dwelling carp Catla catla, but the influence of this pineal hormone on the seasonal activity of testis varies in relation to the reproductive status of the concerned fish.

Control of annual reproductive cycle in the subtropical house sparrow (Passer domesticus): evidence for conservation of photoperiodic control mechanisms in birds

BackgroundIn many birds, day length (=photoperiod) regulates reproductive cycle. The photoperiodic environment varies between different seasons and latitudes. As a consequence, species at different latitudes may have evolved separate photoperiodic strategies or modified them as per their adaptive need. We studied this using house sparrow as a model since it is found worldwide and is widely investigated. In particular, we examined whether photoperiodism in house sparrows (Passer domesticus) at 27°N, 81°E shared features with those exhibited by its conspecifics at high latitudes.ResultsInitial experiment described in the wild and captive conditions the gonad development and molt (only in captives) cycles over a 12-month period. Both male and female sparrows had similar seasonal cycles, linked with annual variations in day length; this suggested that seasonal reproduction in house sparrows was under the photoperiodic control. However, a slower testis and attenuated follicular growth among captives indicated that other (supplementary) factors are also involved in controlling the reproductive cycle. Next experiment examined if sparrows underwent seasonal variations in their response to stimulatory effects of long day lengths. When birds were transferred every month over a period of 1 year to 16 hours light:8 hours darkness (16L:8D) for 17–26 weeks, there was indeed a time-of-year effect on the growth-regression cycle of gonads. The final experiment investigated response of house sparrows to a variety of light-dark (LD) cycles. In the first set, sparrows were exposed for 31 weeks to photoperiods that were close to what they receive in between the period from sunrise to sunset at this latitude: 9L:15D (close to shortest day length in December), 12L:12D (equinox, in March and September) 15L:9D (close to longest day length in June). They underwent testicular growth and regression and molt in 12L and 15L photoperiods, but not in 9L photoperiod. In the second set, sparrows were exposed for 17 weeks to photoperiods with light periods extending to different duration of the daily photosensitivity rhythm (e.g. 2L:22D, 6L:18D, 10L:14D, 14L:10D, 18L:6D and 22L:2D). Interestingly, a slow and small testicular response occurred under 2L and 10L photoperiods; 6L:18D was non-inductive. On the other hand, 14L, 18L and 22L photoperiods produced testicular growth and subsequent regression response as is typical of a long day photostimulation.ConclusionSubtropical house sparrows exhibit photoperiodic responses similar to that is reported for its population living at high latitudes. This may suggest the conservation of the photoperiodic control mechanisms in birds evolved over a long period of time, as a physiological strategy in a temporally changing environment ensuring reproduction at the best suited time of the year.

Failure to Maintain a Suppressed Level of Serum Testosterone during Long-Acting Depot Luteinizing Hormone-Releasing Hormone Agonist Therapy in Patients with Advanced Prostate Cancer

Objectives: It was the aim of this study to analyze the failure rates in achieving or maintaining castrate levels of serum testosterone in patients with advanced prostate cancer treated with the 3-month luteinizing hormone-releasing hormone agonist (LH-RH) therapy. Methods:Total serum testosterone was determined in 234 patients with prostate cancer in a cross-sectional study. A subset of 90 patients submitted to radical prostatectomy was used as the control group (group 1), and 144 patients with advanced prostate cancer under androgen suppression therapy were included in the study group (groups 2 and 3). The study group was divided into 93 patients (group 2) treated with 50 mg daily bicalutamide and LH-RH agonist (maximal androgen blockade, MAB) and 51 patients treated with the LH-RH agonist alone (group 3). Median follow-up after androgen suppression was 42 months. The castrate testosterone level was defined below 50 ng/dl. Results: The mean serum testosterone level was 29.1 ng/dl in patients undergoing MAB (group 2) and 29.5 ng/dl in patients treated with the LH-RH agonist (group 3; p > 0.05). In group 1, the mean serum testosterone was 445.2 ng/dl (p < 0.0001). The rate of patients with a serum testosterone level higher than 50 ng/dl was 10.9% in patients undergoing androgen suppression, 10% in patients with MAB treatment and 12.5% in those with LH-RH agonist therapy (p > 0.05). In group 1, 98.9% of the patients had a serum testosterone level higher than 50 ng/dl. Conclusions: A small but clinically significant rate of patients under 3-month LH-RH agonist therapy fail to achieve or maintain castrate testosterone serum levels. This finding supports the need of monitoring testicular response during LH-RH agonist therapy.

Direct Effect of Progestogen on Gene Expression in the Testis during Gonadotropin Withdrawal and Early Suppression of Spermatogenesis

Testicular production of steroids and gametes is under gonadotropin support, but there is little information as to the molecular mechanisms by which these are regulated in the human. The testicular response to gonadotropin withdrawal is important for the development of effective contraceptive methods. Our objective was investigation of expression of genes in the normal human testis reflecting steroidogenesis, Sertoli cell function, and spermatogenesis after short-term gonadotropin withdrawal and the effects of activating testicular progesterone receptors. We conducted a randomized controlled trial at a research institute. Thirty healthy men participated. Subjects were randomized to no treatment or gonadotropin suppression by GnRH antagonist (cetrorelix) with testosterone (CT group) or with additional administration of the gestogen desogestrel (CTD group) for 4 wk before testicular biopsy. Gene expression was quantified by RT-PCR. Both treatment groups showed similar suppression of gonadotropins and sperm production and markedly reduced expression of steroidogenic enzymes. Addition of progestogen in the CTD group resulted in reduced expression of 5alpha-reductase type 1 compared with both controls and the CT group. Inhibin-alpha and the spermatocyte marker acrosin-binding protein were significantly lower in the CTD but not CT groups, compared with controls, but did not differ between treated groups. Men who showed greater falls in sperm production also showed reduced expression of these three genes but not of the spermatid marker protamine 1. These data provide evidence for direct progestogenic effects on the testis and highlight steroid 5alpha-reduction and disruption of spermiation as important components of the testicular response to gonadotropin withdrawal.