No abstract

The histochemical utilization of 3\g=a\-,6\g=b\-, 1 1 \ g = a \ -,12\g=a\-,16\g=a\-,16\g=b\-,17\g=a\-, 21-and 24-hydroxysteroids in human and mouse testis, human placenta, mouse ovary and rat adrenal has been investigated using a coupling method and the tetrazolium salt, Nitro-BT. 3\g=a\-Hydroxysteroiddehydrogenase was present in the human Leydig cells and placental syntrophoblast, but there was little in rat adrenal zona fasciculata and in mouse ovary; the enzyme is NAD or NADP dependent. 6\g=b\-Hydroxysteroiddehydrogenase was present in human Leydig cells, mouse Leydig cells, placental syntrophoblast, ova, granulosa, theca interna, corpora lutea and interstitial tissue; it is NAD dependent. 11\g=a\-Hydroxysteroiddehydrogenase activity was very poorly developed, being NAD dependent and demonstrable only in human Leydig cells. 12\g=a\-Hydroxysteroiddehydrogenase could be demonstrated in some human Leydig cells; it was both NAD and NADP dependent. 16\g=a\-Hydroxysteroids were very poorly used by all the tissues surveyed. 16\g=b\-Hydroxysteroidsgave an intense histochemical reaction with NAD in human Leydig and Sertoli cells, in placental trophoblast, in adrenal zonae glomerulosa, fasciculata and reticularis and in all ovarian tissues. 17\g=a\-, 21-and 24-hydroxysteroids were poorly utilized by human Leydig cells, but not by the other tissues. The first two were NAD dependent; 24-hydroxysteroid utilization was both NAD and NADP dependent.The techniques used are believed to demonstrate specific hydroxysteroid dehydrogenases because of variations in pyridine nucleotide requirement and in the location in the tissues of different hydroxysteroid dehydrogenases. Moreover, stereoisomers of the same hydroxysteroid behave differently in this system. The role of steroid 5\g=a\-and 5\g=b\-dehydrogenases is discussed in connexion with the histochemical results.

Summary Starch gel electrophoresis showed that Bacillus cereus esterase and catalase are not single enzymes but multimolecular species and that they undergo changes during sporulation. Heat resistant spore catalase was detected in vegetative cells before mature spores were present.

SUMMARY 3β-Hydroxysteroid dehydrogenase activity was studied histochemically in human, monkey, and rat adrenal glands and in human placentae. Tissue sections were incubated separately with each of the following substrates: (1) 3β-hydroxypregn-5-en-20-one (pregnenolone); (2) sodium 3β-sulphoxypregn-5-en-20-one (pregnenolonesulphate); (3) 3β-acetoxypregn-5-en-20 one (pregnenoloneacetate); (4) 3β,16α-dihydroxypregn-5-en-20-one (16α-hydroxypregnenolone); (5) 3β,17α-dihydroxypregn-5-en-20-one (17α-hydroxypregnenolone); (6) ammonium 3β-sulphoxy-17α-hydroxypregn-5-en-20-one (17α-hydroxypregnenolone ammonium sulphate); (7) 3β-hydroxyandrost-5-en-17-one (DHA); (8) 3β-sulphoxyandrost-5-en-17-one (DHA sulphate); (9) 3β-acetoxyandrost-5-en-17-one (DHA acetate); (10) androst-5-ene-3β, 17β-diol (androstenediol). The histochemical results obtained with pregnenolone and DHA as substrates resemble those described by other workers. Using pregnenolone sulphate and 17α-hydroxypregnenolone sulphate, a strong histochemical reaction with diformazan deposition was found in the zona fasciculata of the adrenals of all species and in the placental syntrophoblast. With DHA sulphate an extremely weak histochemical reaction was obtained with the adrenal zona fasciculata, monoformazan only being deposited. The syntrophoblast, however, showed intense 3β-hydroxysteroid dehydrogenase activity when incubated with DHA sulphate. These results accord with recent findings regarding the secretion and metabolism of 3β-sulphoxysteroids. A strong histochemical reaction was also obtained in both adrenal and placental tissues using 17α-hydroxypregnenolone, 16α-hydroxypregnenolone, androstenediol, pregnenolone acetate, and DHA acetate. These steroids have not previously been described as substrates for the histochemical demonstration of 3β-hydroxysteroid dehydrogenase in the adrenal or placenta.

SUMMARY One hundred and thirty-two male Swiss white mice were killed in batches of twelve, between birth and the end of the 10th week of postnatal life inclusive, a total of eleven groups. Sections of testis from every animal were incubated with three steroid substrates to demonstrate 3β-hydroxysteroid dehydrogenase histochemically. The substrates were (1) 3β: 17α-dihydroxypregn-5-en-20-one (17α-hydroxypregnenolone), (2) 3β-hydroxypregn-5-en-20-one (pregnenolone) and (3) 3β-hydroxyandrost-5-en-17-one (DHA). When 17α-hydroxypregnenolone was used as a substrate no 3β-hydroxysteroid dehydrogenase activity was demonstrable in the testis until the end of the 10th week of postnatal life. With pregnenolone as a substrate 3β-hydroxysteroid dehydrogenase activity was demonstrable throughout the age groups studied. It was present at birth and increased progressively until the end of the 6th week of postnatal life. Thereafter the activity decreased progressively during the ensuing 4 weeks. With DHA as substrate activity was again demonstrable in all age groups studied and increased progressively from birth until the end of the 7th week of postnatal life after which a relatively constant high level was maintained. On the basis of these findings the existence of more than one 3β-hydroxysteroid dehydrogenase enzyme is postulated, each enzyme being substrate specific.