ELEVATION OF RHESUS-MONKEY PLASMA LUTEINIZING-HORMONE LEVELS IN RESPONSE TO E-SERIES PROSTAGLANDINS

Experiments were carried out to assess the influence of prostaglandins (viz. PGE1, PGE2 and PGF2α) on plasma concentrations of FSH and LH in the female rhesus monkey. Monkeys were ovariectomized and treated with estradiol benzoate to suppress endogenous gonadotropin levels prior to these experiments. Femoral venous blood was taken at intervals following a single carotid arterial injection of the PG in anesthetized monkeys. FSH and LH concentrations, determined by radioimmunoassay, were not significantly altered in 4 control animals receiving saline (2) or ethanol-saline (2), the vehicles for PGF2α and for the E series PGs, respectively. PGE1 (5mg) effected dramatic elevations of LH within 5 min in 3 animals and the high plasma concentrations were maintained at least for 60 min. Similarly, 5.0 mg of PGE2 effected rapid elevation of LH concentrations, from 2- to 7-fold pre-injection levels in 3 animals. In contrast, FSH levels were not so markedly altered by PGE1 and PGE2, but in general, appeared to be somewhat decreased by these treatments. PGF2α had no effect on plasma FSH and LH concentrations. These data demonstrate the ability of PGs of the E series to elevate plasma LH concentrations in the rhesus monkey and support studies in other species suggesting a modulating role for PGs on gonadotropin secretion or release. © 1978.