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A Sunde

Publications and source records attributed to A Sunde.

42 records · Page 3Linked to original sources
PubMed1982

C-19-steroid 7 alpha-hydroxylation by rat testes. Isolation and identification of: 7 alpha, 17 beta-dihydroxy-5 alpha-androstan-3-one, 5 alpha-androstan-3 alpha, 7 alpha, 17 beta-triol and 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol.

From incubations of testosterone with rat testicular homogenates in the presence of a NADPH-generating system, the following 7 alpha-hydroxylated metabolites could be isolated and identified: 7 alpha, 17 beta-dihydroxy-4-androsten-3-one (7 alpha-hydroxy-testosterone), 7 alpha-17 beta-dihydroxy-5 alpha-androstan-3-one (7 alpha-hydroxy-Dht), 5 alpha-androstan-3 alpha, 7 alpha, 17 beta-triol (7 alpha-hydroxy-3 alpha-A'DIOL) and 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol (7 alpha-hydroxy-3 beta-A'DIOL). To our knowledge this is the first demonstration of the formation of 5 alpha-reduced-7 alpha-hydroxylated metabolites of testosterone in the male gonad. These 5 alpha-reduced-7 alpha-hydroxylated metabolites could also be isolated after incubations of 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-A'DIOL) with testicular homogenates in the presence of A NADPH-generating system. Measured as the sum of 7 alpha-hydroxy-testosterone, 7 alpha-hydroxy-Dht. 7 alpha-hydroxy-3 alpha-A'DIOL and 7 alpha-hydroxy-3 beta-A'DIOL formed using testosterone as substrate, total 7 alpha-hydroxylase activity was six times higher in testes of mature rats than in testes from animals 23 days old. With 3 alpha-A'DIOL as substrate total 7 alpha-hydroxylase in the mature testis was about three times greater than in the sexually immature testis.

Androstane-3,17-diol↗
PubMed1982

Effects of cadmium on survival and morphology of cultured rat Sertoli cells.

The toxicity of different metals on isolated Sertoli cells grown in culture has been investigated. Methyl mercury (CH3HgCl) and mercury chloride (HgCl2) were more toxic than cadmium (CdCl2) which was slightly more toxic than arsenic (As2O3). Isolated peritubular cells and Sertoli cells were equally sensitive to cadmium. Cadmium reduced the Sertoli cell survival over the concentration range of 1--10 microM. Freeze-etch electron microscopy of cadmium-exposed Sertoli cells revealed circular areas of average diameter 500 nm devoid of intramembrane particles in the nuclear membrane, and general signs of degeneration such as vesiculation of the plasma membrane and intramembrane particle aggregation. However, cadmium did not dissolve junctional complexes between Sertoli cells. Isolated Sertoli cells were protected against cadmium-induced damage when the cells were preincubated for 48 h with selenium, zinc or low doses of cadmium. Preincubation with cobalt, FSH, testosterone or oestradiol did not protect against cadmium-induced damage. Cadmium bound to metallothionein had no toxic effects on isolated Sertoli cells.

Animals↗
PubMed1980

Hydroxylation of testosterone in the human testis. Identification of 4-androstene, 7 alpha,17 beta-diol-3-one (7 alpha-hydroxytestosterone) as a metabolite of testosterone.

Homogenates of normal or cryptorchid, human testes were incubated with [3H]testosterone and a NADPH-generating system. [3H]4-andostene,7 alpha,17 beta-diol-3-one (7 alpha-OH-testosterone) was isolated and identified from such incubations. To our knowledge this is the first demonstration that 7 alpha-OH-testosterone is a metabolite of testosterone in the human testis. 4-Andro-stene,6 beta,17 beta-diol-3-one (6 beta-OH-testosterone) and 4-androstene,16 alpha,17 beta-diol-3-one (16 alpha-OH-testosterone) were also identified as testosterone metabolites. The specific activity of both testosterone 6 beta- and 16 alpha-hydroxylase was higher than that of 7 alpha-hydroxylase. Pre-pubertal or cryptorchid human testis tissues seem in our study to have higher testosterone 6 beta- and 7 alpha-hydroxylase activity than normal adult testis tissue.

Adolescent↗
PubMed1979

Metabolism of 5 alpha-androstane-3 beta,17 beta-diol to 17 beta-hydroxy-5 alpha-androstan-3-one and 5 alpha-androstan-3 alpha,17 beta-diol in the rat.

Significant metabolism of 5 alpha-androstane-3 beta,17 beta-diol to 17 beta-hydroxy-5 alpha-androstan-3-one was recorded in several tissues and organs from rats and humans. This bioconversion was further investigated in rat testis homogenates. 5 alpha-Androstane-3 beta,17 beta-diol was readily metabolized to 17 beta-hydroxy-5 alpha-androstan-3-one with NAD and/or NADP added as cofactors. When a NADPH generating system was included in the incubation, 5 alpha-androstane-3 beta,17 beta-diol was metabolized to 5 alpha-androstan-3 alpha,17 beta-diol. Only small amounts of 17 beta-hydroxy-5 alpha-androstan-3-one accumulated under the latter condition.

Androstanols↗
PubMed1977

Production and effects of 7 alpha-hydroxytestosterone on testosterone and dihydrotestosterone metabolism in rat testis.

1. Testicular 7 alpha-hydroxylation of testerone was assayed in cell extracts of rats between 12 and 79 days of age. Maximal 7 alpha-hydroxylase activity was observed about 60 days, while insignificant activity was obtained prior to 42 days of age. 2. 7 alpha-Hydroxytestosterone, a major metabolite of testosterone in mature rat testis, inhibited 5 alpha-reduction of testosterone in cell extracts of mature but not of immature rat testis. 3. Maximal testicular activity of 3 beta-hydroxysteroid dehydrogenase using dihydrotestosterone as substrate was obtained in the presence of NAD, while maximal 3 alpha-hydroxysteroid dehydrogenase activity was observed with NADP. Both enzyme activites were reversible. 4. Sensitivity toward testosterone inhibition of 3-hydroxysteroid dehydrogenase varied greatly with stage of testis development being highest at 25-27 days of age. In contrast to testosterone, 7 alpha-hydroxytestosterone was an inhibitor of 3 alpha-hydroxysteroid dehydrogenase only. In the mature rat testis 7 alpha-hydroxytestosterone may be a naturally occurring inhibitor of dihydrotestosterone and 5 alpha-androstane-3 alpha, 17 beta-diol formation.

Aging↗