EFFECT OF PROSTAGLANDIN-E(2) ON RATE OF DECIDUALIZATION IN RATS

Based on morphology, it has been suggested that prostaglandin E2 (PGE2 ) accelerates the process of endometrial stromal cell differentiation to decidual cells in the rat. The present study investigated this poss ibility, using changes in uterine weight and in endometrial alkaline p hosphatase (ALP) activity as indicators of decidualization. Rats were ovariectomized and treated with one of two steroid protocols; the firs t was identical to that previously used for the study of morphology, t he second a modified protocol which results in greater uterine sensiti zation for decidualization, producing larger amounts of decidual tissu e, thereby making it easier to detect differences between treatments. On the day of uterine sensitization, rats within each treatment protoc ol were given a unilateral intrauterine infusion of phosphate-buffered saline (PBS) or PGE2 plus indomethacin, and killed 24, 48 or 72 h lat er. The time-courses for the increases in uterine weight and ALP activ ity in uterine horns infused with PBS or PGE2 plus indomethacin differ ed between steroid protocols, but within a protocol were statistically indistinguishable. The results do not support the hypothesis that PGE 2 accelerates the process of decidualization but do provide additional support for the notion that PGE2 is a physiological rather than pharm acological mediator of decidualization.