Effect of Median Eminence Implants of FSH, LH or Prolactin on Luteal Function in the Rat¹

Abstract

The effects of a single implant of FSH, LH or prolactin in the median eminence (ME) were observed on duration of pseudopregnancy (PP) and formation of deciduomata in the rat. A ME implant of prolactin on day 1, 4 or 8 of PP invariably reduced the duration of PP (mean = 10.8 days), whereas FSH or LH implants had no effect (13.4–13.9 days). ME implants of prolactin but not of FSH or LH on day 1 or 4 of PP prevented the formation of deciduomata after the uterus was traumatized on day 4 of PP. The increase in uterine weight as a result of deciduomata formation was completely prevented by prolactin but not by FSH or LH. These results indicate that prolactin but not FSH or LH is necessary for luteal maintenance in the rat. (Endocrinology 88: 1273, 1968)