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Biomedical subjects

K Schubert

Publications and source records attributed to K Schubert.

At least 91 records · Page 5Linked to original sources
PubMed1978

[Inhibition of rat liver delta 4-3-ketosteroid-5 alpha-reductase by steroids in vitro].

The inhibition of the hydrogenation of testerone to 5alpha-dihydrotestosterone in microsomes of female rat liver has been studied by progesterone-, testosterone- and estradiol derivatives. In the pregnane series, progesterone, 17alpha-OH-progesterone and its acetate were the strongest inhibitors. In the estradiol series, 3-hydroxy-compounds with a CH2X-substituent at 17alpha-position were stronger inhibitors than the respective 3-methoxy derivatives. The most potent inhibitor till now is an estradiol derivative with a SeCN group in 16alpha-position.

5-alpha Reductase Inhibitors↗
PubMed1977

[Steroid metabolism in primates. XIX. Urinary excretion of C21-steroids in Cercopithecus aethiops and Erythrocebus patas].

In male Cercopithecus aethiops (green monkey; grivet) and Erythrocebus patas (dancing red monkey; patas monkey), the pattern of urinary C21 steroids was estimated and compared with those of man, baboon and rhesus monkey. The results indicate diminished 11 beta- and 17 alpha-hydroxylation in steroid biosynthesis as well as diminished delta 4-3-keto reduction and increased 20 beta-reduction in metabolism in these two species.

Animals↗
PubMed1976

[Steroid metabolism in primates. XVIII. Return to higher levels of 17-ketosteroid excretion in urine after ending a long-term treatment with mestranol/chlormadinone acetate in the baboon].

6 weeks after terminating a long-time application of the ovulation inhibitor Ovosiston (mestranol/chlormadinone acetate) in female baboons, excretion of 17-ketosteroids in urine is still decreased. 6 months after ceasing the preparation, urinary 17-ketosteroid excretion resembles that of the control group.

17-Ketosteroids↗
PubMed1976

[Metabolism of sulfate and phosphate conjugates of 19-nortestosterone enantiomers].

The sulfate and phosphate conjugates of 19-nortestosterone (17beta-hydroxy-estr-4-ene-3-one) and ent-19-nortestosterone (ent-17beta-hydroxy-estr-4-ene-3-one) have been synthesized. The sodium salts of the conjugates were i.v. infused to 2 women. On days 1--4 following application, the 19-nortestosterone and 17-ketosteroid excretion in urine as well as the 19-nortestosterone conjugation have been estimated. The 19-nortestosterone enantiomers were excreted in nearly the same amounts. In comparison to testosterone, the excretion of unchanged steroid (20--50%) is significantly higher. The sulfate conjugates of the enantiomers are not hydrolyzed in vivo, whereas the phosphate conjugates are completely splitted. Hydrolysis of ent-nortestosterone phosphate takes place obviously more slowly. Urinary 17-ketosteroids are significantly increased only following infusion of 19-nortestosterone phosphate.

17-Ketosteroids↗
PubMed1975

[Microbial 3-O-demethylation and 3-O-methylation of estratrienes].

Estradiol-3-methylether, estrone-3-methylether, 17alpha-ethinyl-estradiol-3-methylether and other 17alpha-substituted estratrienes were 3-O-demethylated to free 3-hydroxy compounds by fermentation with Corynebacterium sp. A hydroxy groupp in position 6alpha or 6beta prevented the reaction. The opposite reaction, methylation of the 3-hydroxy group of estratrienes, was performed using Mycobacterium smegmatis. The substrate specifity of this methylation was low. Analogies of these microbial reactions to steroid metabolism in mammalian organism are discussed.

Chemical Phenomena↗
PubMed1975

[Steroid metabolism in primates. XVI. Secretion of corticosteroids in the baboon Papio hamadryas during chronic administration of sodium chloride].

The adrenal steroid secretion was investigated in male baboons (Papio hamadryas) treated for a long time with sodium chloride, in comparison to an untreated control group. In animals treated with NaCl, the secretion of progesterone, 17alpha-hydroxyprogesterone, 11-deoxycortisol, aldosterone and corticosterone was decreased, while cortisone, pregnenolone, 7-keto-cholesterol, 7-keto-DHEA, DHEA and adrenosterone were increased.

Adrenal Cortex Hormones↗