Search PubMed⌕ Search

Biomedical subjects

J B Hay

Publications and source records attributed to J B Hay.

At least 109 records · Page 6Linked to original sources
PubMed1976

Metabolism of androgens in vitro by human foetal skin.

Fresh scalp, genital, chest and axillary skin from human foetuses of 12-41 weeks' maturity was incubated in Krebs improved Ringer I medium with (7alpha-3h)dehydroepiandrosterone, (7alpha-3H)testosterone and (7alpha-3H)androstenedione. The metabolites identified were androstenedione, 5alpha-androstane-3alpha, 17beta-diol, 5alpha-androstane-3beta, 17beta-diol, 5-androstene-3beta, 17beta-diol and testosterone. The results provide evidence for the presence of 3beta-hydroxysteroid dehydrogenase, delta4-5 isomerase, 17beta-hydroxysteroid dehydrogenase, delta4-3-oxosteroid-5alpha reductase and 3alpha-hydroxysteroid dehydrogenase in human foetal skin. There were quantitative differences in the various enzyme activities between different body sites and skin specimens of different gestational age. 5alpha-Reductase activity was particularly high in genital skin. 3beta-Hydroxysteroid dehydrogenase delta4-5 isomerase activity was low in skin from a 12-week foetus, but high in skin specimens from 28-, 38- and 41-week foetuses. 17beta-Hydroxysteroid dehydrogenase activity was already high in the skin of the 12-week foetus and remained so in the older foetuses. These results were correlated with the development of the foetal sebaceous glands, and were in general agreement with a parallel enzyme histochemical study. The role of androgen metabolism in human foetal skin is discussed.

17-Ketosteroids↗
PubMed1975

An unusual pattern of testosterone metabolism in tissue associated with a keratin-filled cutaneous cyst.

Testosterone metabolism was studied in tissues associated with a keratin-filled cutaneous cyst. Instead of the 5alpha-reduced metabolites usually associated with skin steroid metabolism, considerable amounts of 5beta-reduced steroids were found. These included 5beta-androstane-3,17-dione, 17beta-hydroxy-5beta-androstan-3-one, and 5beta-androstane-3beta,17beta-diol. This change in metabolic pattern is discussed.

Adult↗
PubMed1975

The use of radioactive microspheres to quantitate hyperemia in dermal inflammatory sites.

A variety of dermal lesions produced by PGE1, tuberculin, and allogeneic lymphocytes were induced in rabbits, guinea pigs, and sheep, respectively. Microspheres labeled with 85Sr were injected into the ascending aorta, and the distribution of radioactivity in the lesions, saline control sites, and various major organs was assessed. It was concluded that the trapping of the microspheres was related to the degree of hyperemia induced, and that this technique enabled a quantitative measure of the blood flow. PGE1 was found to be a potent mediator of hyperemia and to have a significant effect on the blood flow at a dose of 1 ng. The blood flow to cellular hypersensitivity reactions was measured and the capacity of the skin to accomodate a large increase in flow during the inflammatory response was established.

Animals↗