HORMONAL REQUIREMENTS FOR THE MAINTENANCE OF LUTEAL FUNCTION IN HYPOPHYSECTOMIZED, PSEUDOPREGNANT RATS

Publisher Website
Google Scholar
Abstract
Pseudopregnant rats with traumatized uteri were hypophysectomized on day 6 and injected with various hormones over the next 4 days. Luteal function was assessed on day 10 of pseudopregnancy by weighing deciduomata and determining luteal and plasma levels of progesterone by a competitive protein-binding assay. Daily treatment with 0·25 mg prolactin restored plasma and luteal levels to the values of intact pseudopregnant animals; however, the deciduomata weighed only 55% of control values. Combining oestrone with prolactin restored deciduomata weight to control values without affecting peripheral progesterone levels. Either 200 μg of follicle-stimulating hormone (FSH) or 5 μg luteinizing hormone (LH) could be substituted for oestrone, in conjunction with prolactin, to increase deciduomata weight to control values. Moreover, the combination of prolactin with FSH or LH significantly increased peripheral plasma levels of progesterone beyond the effects of prolactin alone. Higher doses of LH were luteolytic as shown by decreased deciduomata weight and considerable variation in plasma and luteal values of progesterone. LH given alone — either in saline or polyvinyl pyrrolidine — failed to maintain any of the parameters of luteal activity mentioned above. The results reaffirm the primacy of prolactin in vivo as the principal luteotrophic hormone of the rat and indicate that selected doses of LH or FSH play an additive role in further increasing peripheral levels of progesterone.

This publication has 0 references indexed in Scilit: