Stimulation of progesterone synthesis, in corpus luteum cells isolated from 4-amino-3,4-d-pyrazolopyrimidinetreated rats, by cholesterol presented in non-lipoprotein form

AbstractWe have previously shown that the administration of 4-amino-3,4-d-pyrazolopyrimidine (4-APP) to rats reduces progesterone synthesis by cells subsequently isolated from their corpora lutea, and that plasma high density lipoprotein (HDL) can restore this progesterone synthesis to normal. In this paper we demonstrate that a dispersion of phospholipid and cholesterol, but not other sterols, can enhance this 4-APP-disabled progesterone synthesis to the same level as can HDL, thus providing the first direct evidence that cholesterol is the component of HDL upon which rat corpus luteum depends for its ability to synthesize progesterone