androstane

Androstane is a fundamental steroid nucleus, a structure composed of 17 carbon atoms arranged in four rings (A, B, C, and D). This parent structure can be modified in numerous ways, leading to a vast array of steroids. Androstane itself exists in cis and trans forms, differing in how the A and B rings are fused.1

A related compound, androstenedione, is a steroid sex hormone (C₁₉H₂₆O₂) produced by the testes, ovaries, and adrenal cortex. It serves as an intermediate in the biosynthesis of testosterone and estrogen. Testosterone and androstenedione are the primary androgens, with other less active androgens also occurring naturally. The specific orientation of atoms and groups within the steroid molecule, indicated by Greek letters like alpha (α) and beta (β), is crucial for defining its properties and reactivity.231