Effect upon the human myometrium during early pregnancy of the prostaglandin F2 alpha and its analogue 15(S)-15-methyl-PGF2 alpha.

The hysterometric technique has been designed to measure the pharmacological effect of active agents upon the human uterine muscle. The physiological background is the fact that smooth muscle contracts under the influence of mechanical stimulation. By applying hysterometry, the effects on the human myometrium in vivo during early pregnancy of the naturally occurring prostaglandin F2 alpha and its analogue 15(S)-15-methyl-PGF2 alpha have now been evaluated. According to the analysis of the contractile responses, the effects of the agents have been determined quantitatively. The drug effects have been characterized by changes in myometrial response between registrations under basic conditions and during the infusion of the active agent, respectively. It was found that when these drugs were given in the doses usually employed in clinical practice, the effect on contractility of the PGF2 alpha compound was more pronounced than that of the analogue. However, when describing the results on a microgram basis, the 15-methyl-PGF2 alpha was confirmed to be 10-20 times more potent than PGF2 alpha.