Topic
Steroid biosynthesis
About: Steroid biosynthesis is a research topic. Over the lifetime, 1721 publications have been published within this topic receiving 58977 citations.
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122 citations
TL;DR: Radioimmunoassay techniques indicate the presence of testosterone and possibly estrogens in the gonad of the mussel at two different stages in its gametogenic cycle.
121 citations
TL;DR: An overview of human C19 steroid biosynthesis including the production of 11-oxygenated androgens, their transport in circulation and uptake into peripheral tissues, and the mechanisms of intracrinology are conceptualised and reviewed.
120 citations
TL;DR: The results implicate NUR77 as a mediator of cAMP action on StAR transcription in steroidogenic Leydig cells and identify a role for CaMKI in this process.
Abstract: Cholesterol transport in the mitochondrial membrane, an essential step of steroid biosynthesis, is mediated by a protein complex containing the steroidogenic acute regulatory (StAR) protein. The importance of this transporter is underscored by mutations in the human StAR gene that cause lipoid congenital adrenal hyperplasia, male pseudohermaphroditism, and adrenal insufficiency. StAR transcription in steroidogenic cells is hormonally regulated and involves several transcription factors. The nuclear receptor NUR77 is present in steroidogenic cells, and its expression is induced by hormones known to activate StAR expression. We have now established that StAR transcription in cAMP-stimulated Leydig cells requires de novo protein synthesis and involves NUR77. We found that cAMP-induced NUR77 expression precedes that of StAR both at the mRNA and protein levels in Leydig cells. In these cells, small interfering RNA-mediated NUR77 knockdown reduces cAMP-induced StAR expression. Chromatin immunoprecipitation assa...
120 citations
TL;DR: In this paper, ovarian tissue from one normal subject and from 9 patients with polycystic ovarian disease was incubated with progesterone-4-C-14, 5-pregnenolone-1/4/C/14 or 19-hydroxyandrostene dione, which resulted in a failure to synthesize estrogen and in an accumulation of testosterone, dehydroepiandrosterone and other C19 metabolites.
Abstract: Ovarian tissue from one normal subject and from 9 patients with polycystic ovarian disease was incubated with progesterone-4-C-14, 5-pregnenolone-4-C-14, testosterone-4-C-14 or 19-hydroxyandrostene dione. In normal tissue, 17-hydroxylation, 20-ketone reduction, side-chain cleavage, formation of subsequent 19-hydroxy and 19-aldo metabolites and aromatization to estradiol-17β were demonstrated. In the polycystic tissue, deficiencies of aromatization, 17-hydroxy lation and 3β-ol dehydrogenase activity were found. This resulted in a failure to synthesize estrogen and in an accumulation of testosterone, dehydroepiandrosterone and other C19 metabolites. These disorders only partially explain the associated clinical findings, and it is not known whether they are primary defects, secondary to extra-ovarian influences, or a combination of the two.
120 citations