This study was designed to evaluate the effect of acute (2 h daily) and repeated (2 h daily for 2 or 10 consecutive days) immobilization stress (IMO) on: 1) the steroidogenic machinery homeostasis; 2) cAMP signaling; and the expression of receptors for main markers of 3) adrenergic and 4) glucocorticoid signaling in Leydig cells of adult rats. The results showed that acute IMO inhibited steroid...

We found that 3α-hydroxysteroid dehydrogenase (3α-HSD) from Pseudomonas sp. B-0831 can catalyze the carbonyl reduction of non-steroid substrates, such as metyrapone and p-nitrobenzaldehyde, in addition to the activity of 3α-hydroxysteroid dehydrogenase. The results of an inhibition study in metyrapone reduction by androsterone and cholic acid indicated that metyrapone bound to the same catalyti...

Tetrahydrobiopterin (BH(4)) is a cofactor for aromatic amino acid hydroxylases and nitric oxide synthase. The biosynthesis includes two reduction steps catalyzed by sepiapterin reductase. An intermediate, 6-pyruvoyltetrahydropterin (PPH(4)) is reduced to 1(')-oxo-2(')-hydroxypropyl-tetrahydropterin (1(')-OXPH(4)) or 1(')-hydroxy-2(')-oxopropyl-tetrahydropterin (2(')-OXPH(4)), which is further c...

Previous studies with the aid of deuterium as a tracer have shown that alcohol dehydrogenase (1)) lactic dehydrogenase (2)) malic dehydrogenase (3)) and a /?-hydroxysteroid dehydrogenase (4) all catalyze the direct transfer of hydrogen between their respective substrates and the para position of the nicotinamide ring of DPN.’ This hydrogen transfer was also shown to be stereospecific for the DP...

A method is described for the culture of rat ovarian surface epithelial cells, i.e., the cellular component thought to be the source of most ovarian cancers. These cells in culture have a characteristic epithelial morphology which distinguishes them from other ovarian cell types. Cultured surface epithelial cells are histochemically positive for 17ß-hydroxysteroid dehydrogenase and negative fo...

Background: We have recently discovered that human type 12 17β-HSD (h17β-HSD12), a homolog of type 3 17β-HSD, is a new estrogen-specific 17β-hydroxysteroid dehydrogenase involved in the production of estradiol (E2). To further characterize this estradiol-producing enzyme, we have isolated the corresponding cDNA in the cynomolgus monkey (Macaca fascicularis), characterized its enzymatic activiti...

CONTEXT Primary pigmented nodular adrenocortical disease (PPNAD) can lead to steroid hormone overproduction. Mutations in the cAMP protein kinase A regulatory subunit type 1A (PRKAR1A) are causative of PPNAD. Steroidogenesis in PPNAD can be modified through a local glucocorticoid feed-forward loop. OBJECTIVE Investigation of regulation of steroidogenesis in a case of PPNAD with virilization. ...