Abstract
Summary
Previous findings in this laboratory that AVT inhibited the preovulatory surge of LH and subsequent ovulation prompted the present study demonstrating that AVT effects a marked suppression of the prolactin surge during proestrus, but does not affect the concurrent surge of FSH. Microgram amounts of AVT (administered from 1300 to 1600 hr on the afternoon of proestrus) suppressed the prolactin surge significantly, relative to saline-treated controls and comparable doses of antidiuretic hormone and oxytocin (P < 0.001); and prolonged administration with increased amounts of AVT (up to 16 μg over the period from 0900 through 1600 hr) had no effect on the FSH surge. These results support earlier suggestions that different mechanisms are involved in the cyclic release of LH and FSH and that the surge of FSH is minimally involved in ovulation in the cycling rat.
These investigations were supported in part by the Levi J. and Mary Skaggs Foundation of Oakland, California. We are indebted to Alicia Sagasay and Robert Schlegel for technical assistance.
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