Bisphenol A (BPA) is an endocrine disruptor used in a variety of consumer 
products. Exposure to BPA leads to alterations in steroidogenesis of ovarian 
granulosa cells. Here, we analyzed the mechanism by which BPA alters 
progesterone biosynthesis in immature rat granulosa cells. BPA increased 
expression of steroidogenic acute regulatory protein (StAR), cholesterol 
side-chain cleavage enzyme and 3β-hydroxysteroid dehydrogenase in granulosa 
cells; however, BPA prevented the basal and the FSH-induced progesterone 
production. BPA caused sequestration of cholesterol to the perinuclear area, as 
evident by the Filipin staining. BPA decreased mRNA expression of ATP binding 
cassette transporter-A1 (Abca1) and increased level of sterol regulatory element 
binding protein 1. Addition of exogenous cell-permeable cholesterol restored the 
effect of BPA on Abca1 and Star mRNA expression and partially reversed BPA's 
effect on progesterone production. These results indicate that exposure to BPA 
disrupts cholesterol homeostasis leading to decreased progesterone production in 
immature rat granulosa cells.