Synthesis and Release of Prolactin and GH in vitro from the Anterior Pituitaries of Virgin or Pregnant Mice

The secretory activities of prolactin and GH of the mouse anterior pituitary were determined from 14C-leucine incorporation in vitro into these hormones. Prolactin and GH of the mouse anterior pituitary were fractionated by disc electrophoresis on polyacrylamide gel.Neither synthesis nor release of prolactin and GH was different between estrus and diestrus in C3H/He strain of virgin mice. No relation existed between the number of placentae and the pituitary secretory activities of these hormones on day 19 of pregnancy when the number of placentae was adjusted to 1-8 each on day 8. Synthesis of prolactin and GH was significantly higher and percent release of these hormones was lower on day 19 of pregnancy than during virginal stages.