Effect of Reserpine on Prolactin-Inhibiting Activity of Rat Hypothalamus12

Publisher Website
Google Scholar
Abstract
Previous studies have shown that the hypothalamus contains a factor(s) which inhibits prolactin synthesis and release in vitro. The present experiments were undertaken to determine whether reserpine acted by depressing hypothalamlc production of "prolactin-inhibitlng factor" (PIF) in vivo, and whether it could reduce the inhibitory effect of hypothalamic tissue on pituitary prolactin release in vitro. Hypothalamic extract from reserpine-treated rats had no significant effect on prolactin release by rat anterior pituitary when incubated in a Dubnoff shaker at 37[degree]C for 2 hr. whereas hypothalamic extract from control cycling rats inhibited prolactin release by 54%. When reserpine was added to a medium containing anterior pituitary halves and hypothalamic pieces, 83-92% more prolactin was released than in medium containing the corresponding anterior pituitary halves and hypothalamic pieces incubated without reserpine. Reserpine had no effect on prolactin release when incubated with anterior pituitary alone. These results indicate that reserpine can delete the rat hypothalamus of PIF when administered in vivo, and can act directly on the hypothalamus in vitro to depress PIF release.