Linda Ogren

Prolactins of pregnancy and their cellular source.

Publisher Summary This chapter discusses the biochemistry, mechanism, and regulation of secretion along with the functions of the pituitary hormones prolactin (PRL) and growth hormone (GH). The placentas of numerous species produce hormones that are structurally and functionally similar to the PRL and GH, which are 20–25K molecular weight proteins that regulate various processes, including mammary gland differentiation, steroidogenesis, somatic growth, and intermediary metabolism. The most extensively studied placental PRL-like hormones are the placental lactogens (PLs). The PLs differ from one another in size and primary function, and some species produce more than one hormone that is a PL. The chapter summarizes the nomenclature used to describe PLs in various species. The maternal component of the placenta—the decidua—also produces PRL-like substances in some species. The primate decidua secretes a molecule that appears to be structurally identical to pituitary PRL. The rat decidua produces a substance designated decidual luteotropin, which has PRL-like biological activity but is not identical to rat pituitary PRL.

Effects of neonatal treatment with diethylstilbestrol and 17α-hydroxyprogesterone caproate on in vitro pituitary prolactin secretion

The effects of neonatal hormone treatment with diethylstilbestrol (DES) and 17 alpha-hydroxyprogesterone caproate (HPC) on days 1-5 of life on serum prolactin (PRL) levels and 3H-PRL synthesis and release were studied in C3H/MTV+ mice at 2, 4, 6, 8 and 10 weeks of age. Neonatal treatment of mice with 2.5 micrograms/day DES was the only treatment that affected the developmental pattern of serum PRL levels. Serum PRL levels were significantly decreased at 6 wks of age with this dose of DES. Neonatal treatment with 2.5 micrograms/day DES and 150 micrograms/day HPC affected the developmental pattern of H-PRL synthesis by the pituitary. At 10 wks of age 3H-PRL synthesis was significantly decreased by these doses of DES and HPC. The percent of 3H-PRL released did not differ between neonatally hormone treated and control animals, suggesting that neonatal treatment affected mechanisms that regulate PRL synthesis but not those that regulate release.