Altered Bile Acid Physiology during Lactation in the Rat

There is evidence that the rate of bile acid secretion increases significantly during lactation in the rat. We show that this increase in secretion rate is accompanied by an expanded bile acid pool and that occasioning the enhancement of both pool size and secretion is an increase in bile acid synthesis. The hypothesis is advanced that maternal prolactin, promoted by suckling young, amplifies cholesterol-7-alpha-hydroxylase, the rate-limiting enzyme in bile acid biosynthesis, and perhaps HMG-CoA reductase, the rate-limiting enzyme in cholesterogenesis.