Steroid biosynthesis

About: Steroid biosynthesis is a research topic. Over the lifetime, 1721 publications have been published within this topic receiving 58977 citations.

Peripheral-Type Benzodiazepine Receptor

Abstract: Eukaryotic steroid hormones, derived from cholesterol, are involved in the maintenance of the organism’s homeostasis, adaptability to the environment, and developmental and reproductive functions. In addition to the well-defined actions in peripheral tissues, steroids have pleiotropic actions on the central nervous system (CNS), where they control a number of neuroendocrine and behavioral functions. Thus, comprehension of the molecular systems underlying the control of steroid hormone biosynthesis is essential for the study and treatment of a multitude of physiological disorders.

Lutropin/choriogonadotropin stimulate the proliferation of primary cultures of rat Leydig cells through a pathway that involves activation of the extracellularly regulated kinase 1/2 cascade.

Abstract: Primary cultures of progenitor and immature rat Leydig cells were established from the testes of 21- and 35-d-old rats, respectively. The cell population remained homogeneous after 4–6 d in culture as judged by staining for 3β-hydroxysteroid dehydrogenase, but the cells were unable to bind 125I-human chorionic gonadotropin (hCG) or to respond to hCG with classical LH receptor (LHR)-mediated responses, including cAMP and inositol phosphate accumulation, steroid biosynthesis, or the phosphorylation of ERK1/2. Infection of primary cultures with recombinant adenovirus coding for β-galactosidase showed that approximately 65% of the cells are infected. Infection with adenovirus coding for the human LHR (hLHR) allowed for expression of the hLHR at a density of approximately 25,000 receptors per cell and allowed the cells to respond to hCG with increases in cAMP and inositol phosphate accumulation, steroid biosynthesis, and the phosphorylation of ERK1/2. Although progenitor and immature cells were able to respond...

Dual Regulation of 3β-Hydroxysteroid Dehydrogenase, 17α-Hydroxylase, and Dehydroepiandrosterone Sulfotransferase by Adenosine 3′,5′-Monophosphate and Activators of Protein Kinase C in Cultured Human Adrenocortical Cells

Abstract: The relationship between cAMP and protein kinase C in the regulation of 3 beta-hydroxysteroid dehydrogenase (3 beta HSD), 17 alpha-hydroxylase, and sulfotransferase was examined in human fetal adrenocortical cells under defined serum-free conditions in culture. Forskolin induced 3 beta HSD and 17 alpha-hydroxylase in a dose-dependent manner, with maximal effects at 10 microM. 12-O-Tetradecanoyl phorbol 13-acetate (TPA) at 1 nM depressed the induction of 17 alpha-hydroxylase activity by forskolin by more than 95% and increased the stimulation of 3 beta HSD activity by forskolin by 4- to 5-fold. Increases were maximal at 48-72 h of incubation. Dehydroepiandrosterone sulfotransferase activity increased over 48 h when cells were transferred to serum-free defined medium. Addition of 10 microM forskolin stimulated sulfotransferase activity only when cells remained in 10% serum. TPA at 1 nM inhibited the increase in sulfotransferase activity. The concentration of TPA required for inhibition of forskolin-stimulated 17 alpha-hydroxylase and sulfotransferase activity was similar to that required for enhancement of forskolin-induced 3 beta HSD activity, suggesting that comparable levels of C kinase activation are involved in these events. Angiotensin II, carbachol, epidermal growth factor, and fibroblast growth factor had actions similar to those of TPA on one or more of these enzyme activities. TPA also had similar actions on enzyme activities when they were stimulated by cAMP analogs rather than by forskolin. These studies suggest that adrenal steroid biosynthesis is under dual regulation by cAMP and protein kinase C. cAMP induces enzymes required for synthesis of 17 alpha-hydroxylated steroids, including the adrenal androgens. Activation of protein kinase C may play a complementary role by enhancing the induction of enzymes required for non-17 alpha-hydroxylated steroid biosynthesis and inhibiting those involved in the synthesis of androgens.