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Biomedical subjects

D Boucher

Publications and source records attributed to D Boucher.

At least 127 records · Page 7Linked to original sources

[Biological assay of hypophyseal gonadotropins in the male rat (statistical study)].

The reproductibility, the experimental and statistical procedures of FSH and LH bioassays are studied. The estrogen pretreatment of animals increases, considerably the responsiveness and reliability of the LH bioassays. FSH levels have been determined, by the methods for parallel line assays, in the pituitary gland of normal rats and three days or seventeen days orchiectomized rats.

Animals↗

[Action of an ovulation stimulator on the genital function of the female rat].

Effect of cyclofenil on genital function implied organs, is studied in cyclic female rats injected s. cut: 0.5, 5 or 50 mg/kg/day, during 12 days. The treatment increases pituitary, adrenal and uterine weights, decreases ovarian weight, adrenal and ovarien cholesterol. These data suggest that cyclofenil acts directly or undirectly at different levels of hypothalamo-pituitary-genital axis with central inhibition and light peripheral stimulation.

Adrenal Glands↗

[Interrelationship between adrenal cortex and genital apparatus of the male rat].

Interactions between gonadal hormones and adrenocortical function have been studied in the male rat. After injection (im) of testosterone, the accessory reproductive organs are more stimulated in the castrated rats than in the castrated adrenalectomized rats. Gonadectomy increases lipids, cholesterol and corticosterone in adrenal glands and plasma corticosterone levels. Testosterone reverses these effects.

17-Ketosteroids↗

Pituitary gonadal function in infertile men with varicocele.

Infertile men with varicocele or idiopathic infertility were compared with a control group. Spermocytograms were taken and the following radioimmunological plasma analyses carried out: testosterone, FSH and LH before and after 50 micrograms LRH, Prolactin (PRL) before and after 200 micrograms TRH; in addition, 8 patients with varicoceles and 3 controls received LRH intravenously (0.4 microgram/min.) for 4 hours. The binding of [125I] human chorionic gonadotrophin (hCG) to testicular tissue obtained by biopsy from 10 infertile men was also investigated. Of the parameters studied, no differences were found between the unilateral or bilateral varicoceles. In the two groups of infertile men, sperm motility and percentage normal forms were similar and significantly lower than in controls. As compared to the controls, in the groups of infertile men, basal LH and testosterone levels were no different but basal FSH levels was increased, basal PRL was higher (p less than 0.05) in the varicocele group. Responses of the LH, FSH and PRL to LRH and TRH stimulations were generally higher in infertile men than in controls. As compared to the idiopathic infertile men, testosterone levels and responses of plasma FSH to LRH injection were lower in varicocele group. Moreover, in infertile men with varicocele, age was correlated negatively with sperm motility and testosterone level and it was correlated positively with LH response to LRH injection. For each patient, testicular tissue was able to specifically bind [125I]hCG, but in some cases of varicoceles, hCG binding capacity was different in the two testes and seemed higher than that observed in men with obstructive azoospermia. These results suggest: 1) dysfunction in both spermatogenesis and Leydig cells with a compensatory hyperfunction of the pituitary gland in infertile men with varicocele; 2) worsening in Leydig cells and tubular lesions with longer duration of varicocele; and 3) absence of any gross abnormality in hCG binding to its specific receptors in the testis of men with varicocele. These data suggest varicoceles may play a causal role in infertility.

Adult↗

Bromocriptine, a dopamine agonist, directly inhibits testosterone production by rat Leydig cells.

We investigated the direct effects of bromocriptine (BR) on both basal and hCG-stimulated testosterone production by rat collagenase-dispersed Leydig cells. In a final volume of 2.2 ml, 2.10(6) Leydig cells were incubated at 33 degrees C for 3 h either alone or with various amounts of hCG (1. 10. 10(2). 10(3). 10(4) mUI/vial) and BR (1.5 10(-9), 1.5 10(-7), 1.5 10(-5) M); BR was dissolved in 20 microliters of ethanol. BR (1.5 10(-5) M) decreased significantly both basal and hCG-stimulated testosterone production whereas at lower doses, BR had no effect. These results suggest that the dopamine itself may regulate rat Leydig cell function and that there is room for criticism of BR-induced hypoprolactinemia as an experimental model to study the effect of prolactin on the androgenic function.

Animals↗

Effect of pineal gland on testosterone release in vitro.

We studied the effect of hCG, aminoglutethimide and pineal effluent on the basal testosterone secretion by superfused adult rat interstitial cells. The period used to determine the mean rates of release was 120-240 min. after the start of superfusion i.e. when basal secretory rate was stable. A 2 h administration of hCG (10 mUI/ml) induced a rapid increase in testosterone output while aminoglutethimide (100 microM) decreased it. Basal testosterone release was not modified when interstitial cells were superfused with effluent of a chamber containing 1, 2 or 4 pineal glands. These results suggest that pineal secretory products exert no direct acute action on testosterone biosynthesis by rat interstitial cells.

Aminoglutethimide↗

Modulation of Leydig cell testosterone production by secretory products of macrophages.

Unstimulated macrophages from testes inhibited the production of testosterone by Leydig cells from adult, but not immature, Sprague-Dawley rats (significant after 48 h). Similar results were observed with unstimulated macrophage-conditioned media, suggesting that the observed effect was mediated by one or more secretory products. None of these substances was interleukin-1, since macrophage supernatants tested negative in an interleukin-1 alpha and interleukin-1 beta sensitive, thymocyte assay. Interleukin-6 was detected by a B cell proliferation assay. After stimulation by LPS, testicular macrophages enhanced testosterone production by Leydig cells from adult and immature rats. This enhancement was dose-dependent and required low concentrations (but over 2.5%) of conditioned media. Interleukin-1 and interleukin-6 activities were detected in LPS-stimulated macrophage supernatants. Supernatants of LPS-stimulated, human monocytes had similar effects on Leydig cells. They were rich in interleukin-1, interleukin-1 receptor antagonist and interleukin-6. The present study suggests that, in adult rats, testicular macrophages modulate Leydig cell steroidogenesis by secretory products whose secretion depends on the physiological state of macrophages. The factor or factors responsible for stimulation are not species-specific. The effect cannot be accounted for by variations in the concentration of the above mentioned interleukins in macrophage supernatants.

Animals↗

Effect of short-term starvation on Leydig cell function in adult rats.

An experiment was carried out to analyze the effect of 3 days of starvation on the Leydig cell function in adult rats. Starvation markedly decreased plasma insulin and testosterone levels (p < .05). The weight of testes was maintained, whereas the testicular interstitial fluid volume decreased (p < .05). The level of testosterone decreased in this fluid (60%), whereas insulin levels showed no significant change. Purified Leydig cells showed normal LH/hCG binding in fasted rats but low insulin binding. The ability of these cells to produce testosterone in vitro was normal under both basal conditions and hCG stimulation in the absence and presence of insulin in the incubation medium. These data suggest that there is no gross impediment in the Leydig cell capacity to produce testosterone that might explain the starvation-associated decrease in plasma testosterone.

Animals↗