CONTROL OF HAMSTER FERTILITY WITH PROSTAGLANDIN F2α IMPLANTS

Abstract

ABSTRACT Prostaglandin, PGF2α, freely permeates polyacrylamide (PAA) during in vitro incubation in saline. In contrast, Silastic tubing was found to be comparatively impervious and subsequently was discounted as a possible implant medium for PGF2α in these experiments. Subcutaneous and vaginal PAA implantation of 20, 75 and 100 μg PGF2α, 2 days after mating, significantly reduced (mainly at the higher levels) the number of female hamsters found to be pregnant upon autopsy, 12 days p. c. Subcutaneous injection and vaginal douche were less effective means of administration. Local application of the drug to the vagina was associated with lower pregnancy rates than was parenteral administration. When PAA implants with 0.5 and 5 mg PGF2α were given (sc injection) on the second day after mating and 5 mg PGF2α was implanted an equal interval prior to mating, it became evident that the former approach was at least ten times more effective in lowering the pregnancy rate in hamsters. This dependence on the time of PGF2α implantation is attributed to rapid release of the drug from these implants and to the existence of a sensitive phase in the initial stages of pregnancy.