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Biomedical subjects

R Morfin

Publications and source records attributed to R Morfin.

8 recordsLinked to original sources

Neurosteroids: pregnenolone in human sciatic nerves.

The characterization and quantification of pregnenolone in human sciatic nerves were undertaken, following previous demonstration of the synthesis of this steroid in rat brain oligodendrocytes, to explore the hypothesis that Schwann cells may demonstrate the same biosynthetic activity. Pregnenolone was definitively identified by mass spectrometry and quantified by specific radioimmunoassay. Its concentration (mean +/- SD, 63.9 +/- 45.9 ng/g of wet tissue, n = 12) was greater than or equal to 100 times the plasma level and concentration found in tendons and muscle. No correlation was found with sex or age. Free dehydroepiandrosterone as well as sulfate and fatty acid esters of pregnenolone and dehydroepiandrosterone were also measured. Results are discussed in terms of the concept that these "neurosteroids" may be synthesized in the peripheral nervous system.

Adult

[Evidence of 5 alpha-androstane-3 beta, 6 alpha, 17 beta-triol and of 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol in the anterior pituitary of the prepuberal male rate].

Incubation of 3H-5 alpha-androstane-3 beta, 17 beta-diol with anterior pituitaries from immature male Rats led to the major production of polar radio-metabolites. Of these, 53 and 27% were identified with 5 alpha-androstane-3 beta, 6 alpha, 17 beta-triol and 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol, respectively. The formation of these trihydroxysteroids may be involved in the intracellular regulation of 5 alpha-androstane-3 beta, 17 beta-diol levels.

Androstane-3,17-diol

Pituitary metabolism of 5alpha-androstane-3beta-17beta-diol: intense and rapid conversion into 5alpha-androstane-3beta,6alpha,17beta-triol and 5alpha-androstane-3beta,7alpha, 17beta-triol.

In the male rat pituitary, 5alpha-androstane-3beta, 17beta-diol (3beta-diol) is extensively metabolized into polar steroids. They were identified as 5alpha-androstane-3beta, 6alpha-17beta-triol (6alpha-triol) and 5alpha-androstane-3beta, 7alpha, 17beta-triol (7alpha-triol). 6-alpha-Triol represents 53% and 7alpha-Triol 28% of the total 3beta-diol metabolites. The remaining percentage is related to 6beta and 7beta isomers. The biological role of triols is still unknown.

Androstane-3,17-diol

[7 alpha-Hydroxylation of 5 alpha-androstane-3 beta, 17 beta-diol in normal and hyperplastic human prostate].

Incubation of 4-14C-5 alpha-androstane-3 beta, 17 beta-diol with human normal and hyperplastic prostate minces led to the NADPH-dependent production of a major polar radiometabolite which was identified as 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol and proved the presence of a 3 beta-hydroxysteroid-7 alpha-hydroxylase in prostate. Such evidences may bring new leads for the study of the mechanisms of androgenic steroid action in the prostate gland.

Androstane-3,17-diol

[7-alpha-Hydroxylation of 5 alpha-androstane-3 beta, 17 beta-diol in human normal and hyperplastic prostates].

Incubation of 4-14C-5 alpha-androstane-3 beta, 17 beta-diol with human normal and hyperplastic prostate minces led to the NADPH-dependent production of a major polar radiometabolite which was identified as 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol and proved the presence of a 3 beta-hydroxysteroid-7 alpha-hydroxylase in prostate. Such evidences may bring new leads for the study of the mechanisms of androgenic steroid action in the prostate gland.

Adolescent

[Is the prostatic adenoma of hormonal origin].

Prostatic adenoma develops at the site of the periurethral glands. The concentration of 5alpha-dihydrotestosterone seems greater at the center of the adenoma than in the overlying prostate. This suggests that medical treatment of prostatic adenoma might be feasible using substances inhibiting the 5alpha-reduction of testosterone.

Aged

[Testosterone and prostatic cancer (author's transl)].

Hormono-dependent epithelial cells of the prostate gland loose their histologic and cytologic differentiation when becoming neoplastic. Such loss of differentiation is related to a change in testosterone metabolism measured by the testosterone metabolites ratio (17 beta-hydroxy/17-oxometabolites). This ratio decreases with differentiation losses and increasing independence from androgenic steroids. Knowledge of that ratio is suggested, prior to the starting of antiandrogenic therapies.

Biopsy