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Biomedical subjects

J A Mahoudeau

Publications and source records attributed to J A Mahoudeau.

At least 37 records · Page 2Linked to original sources
PubMed1975

[The effect of gonadotropic hormones and the fetal hypophysis on testosterone production by the testis of 18 day mouse fetuses in organ culture].

The production of testosterone (measured by radioimmuno-assay) by the 18-day-old mouse fetal testis may be stimulated specifically by ovine LH (1 ng, p less than 0.005) and HCG in organ culture. A stimulation by FSH is observed only with high doses (10 mug, p less than 0.0005). Prolactin and ACTH have no effect. Age-matched fetal pituitaries increase significantly the testosterone production in the culture medium (p less than 0.0005).

Adrenocorticotropic Hormone↗
PubMed1975

Dissociated responses of plasma testosterone and estradiol to human chorionic gonadotropin in adult men.

Plasma testosterone (T), dihydrotestosterone (DHT) and estradiol (E2) were determined by radioimmunoassay in 10 normal males receiving hCG im 5000 IU on days 1, 2 and 3. The mean increase of plasma steroid on days 2, 3 and 1, respectively, was: 1.42, 1.79 and 1.87 times for T; 1.17, 1.56 and 1.49 times for DHT; 4.04, 3.29 and 2.33 times for E2. While T was still significantly increasing from day 2 to day 4, E2 significantly decreased. A positive correlation (P less than 0.01) was found between the basal T and the E2 peak after hCG, suggesting a release of E2 from a storage compartment in the testis. No significant change of either steroid was detected 4 h after the first hCG injection. In 6 cases of primary male hypogonadism, the mean basal values of T to hCG was defective, despite considerable individual variations. In 14 males with gonadotropin deficiency, basal values of T and E2 were very low; the T response to hCG ranged from undetectable to dramatic, and was correlated with the degree and duration of previous exposure to gonadotropin; and impaired response of E2 in all cases porvides a better estimate of the actual gonadotropin deficiency.

Adolescent↗
PubMed1971

The metabolic clearance rate and origin of plasma dihydrotestosterone in man and its conversion to the 5-alpha-androstanediols.

Dihydrotestosterone metabolism was studied with a constant infusion technique in three men, three women, five hirsute women, and four estrogen-treated hirsute women. The mean dihydrotestosterone metabolic clearance rate was higher in men (336 liters/24 hr per m(2) [range, 239-448]) than in women (153 liters/24 hr per m(2) [range, 108-184]). The metabolic clearance rates in hirsute patients were intermediate between those men and women and were decreased by estrogen treatment. These observations demonstrate similarities in the metabolic rates of testosterone and dihydrotestosterone. The conversion of plasma testosterone and androstenedione to dihydrotestosterone was studied in men and hirsute women. Approximately 4 and 2% of plasma testosterone and androstenedione, respectively, were converted to plasma dihydrotestosterone in both groups. From these observations it was determined that a major fraction of plasma dihydrotestosterone was derived from these plasma precursors rather than from glandular secretion. Both 5alpha-androstan-3alpha,17beta-diol (3alpha-diol) and 5alpha-androstan-3beta,17beta-diol (3beta-diol) were identified in plasma during dihydrotestosterone and testosterone infusions. The conversion ratio of dihydrotestosterone to 3alpha-diol (C(BB) (DHT-3alpha)) was greater than the conversion ratio to the 3beta-isomer (C(BB) (DTH-3beta)) in all the patients studied. Both C(BB) (DHT-3alpha) and C(BB) (DHT-3beta) were higher in men (mean values of 0.151 [range, 0.110-0.222] and 0..031 [range, 0.022-0.042]) than in women (means of 0.044 [range, 0.037-0.048] and 0.012 [range 0.010-0.013]). A smaller fraction of testosterone was converted to 3alpha-diol and 3beta-diol.

Adrenocortical Hyperfunction↗