THE EFFECT OF DIFFERENT PROSTAGLANDINS ON HUMAN MYOMETRIUM IN VITRO.

The effect of different prostaglandins present in human semen--PGE1 PGE2 PGE3 PGF1x PGF2x and a crude extract of human semen HSF-PG--were investigated and compared on human myometrium in vitro. The concentration of the prostaglandins in HSF-PG was determined with a new chemical method. All the PGE-compounds inhibited the spontaneous motility of human non-pregnant myometrium in vitro. In most cases the effect of HSF-PG was similar to that obtained with the PGE-compounds. The PGE-compounds also inhibited the motility of pregnant myometrium. The stimulatory effect of the PGF-compounds tested was more pronounced on pregnant myometrium. The sensitivity of non-pregnant myometrium to the different prostaglandins and to HSF-PG was dependent on the extracellular concentration of potassium and calcium. An increased potassium concentration made the myometrium less sensitive to the PGE-compounds and to HSF-PG but enhanced the effect of the PGF-compounds. A decrease in the calcium concentration to 1/3 of the normal concentration increased the sensitivity of the myometrium to HSF-PG and to PGE1 predominantly at the ovulation time. The sensitivity of the non-pregnant myometrium to the PGE compounds and to HSF-PG in vitro varied significantly during the different phases of the menstrual cycle with the sensitivity of the myometrium most pronounced at ovulation time.