Description_x000D_ Application_x000D_ 5-Pregnen-3β-ol-20-one is suitable for use:_x000D_ • as a substrate for 3β-HSD at a concentration of 1 μg/mL to study the time-dependent effect of reduced oxygen tension on 3β-hydroxysteroid dehydrogenase (3β-HSD) activity_x000D_ • as a progestin precursor to study the effects of splenic macrophages on progestin secretion of luteal cells_x000D_ • in the testicular interstitial cell culture medium at a concentration of 15mg/mL_x000D_ Packaging_x000D_ 1, 5, 25, 100 g in poly bottle_x000D_ Biochem/physiol Actions_x000D_ One of a small number of "neurosteroids," steroids synthesized in the brain rather than peripheral sources. Decreased levels of these neurosteroids has been implicated in rodent cognitive decline with age, but studies in humans have been contradictory._x000D_ Testosterone production in rats occurs in Leydig cells of the testis via the Δ4 pathway. Cholesterol is first converted to pregnenolone, then to progesterone, and finally to testosterone. Pregnenolone is the key neurosteroid synthesized in steroidogenic glands. It is also present as a sulfate ester that serves as an antagonist of GABAergic neurons by interacting with γ-aminobutyric acid (GABA) receptor._x000D_ Other Notes_x000D_ Tandem Mass Spectrometry data independently generated by Scripps Center for Metabolomics is available to view or download in PDF. P9129.pdf Tested metabolites are featured on Scripps Center for Metabolomics METLIN Metabolite Database. To learn more, visit sigma.com/metlin.