Wiktionary
pregnane
n. (context organic compound English) The parent hydrocarbon for a range of steroids including the progesterones
Wikipedia
Pregnane
Pregnane is, indirectly, a parent of progesterone. It is a parent hydrocarbon for two series of steroids stemming from 5α-pregnane (originally allopregnane) and 5β-pregnane (17β-ethyletiocholane).
5β-Pregnane is the parent of the progesterones, pregnane alcohols, ketones, and several adrenocortical hormones and is found largely in urine as a metabolic product of 5β-pregnane compounds.