Effects of prostanoids on the rat's myometrium in vitro during pregnancy

• Published in: Biology of reproduction Vol. 46; no. 3; pp. 392 - 400
• Main Authors: CRANKSHAW, D. J, GASPAR, V
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01-03-1992
• Subjects: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Biological and medical sciences; Dinoprost - pharmacology; Dinoprostone - pharmacology; Female; Fundamental and applied biological sciences. Psychology; Hormone metabolism and regulation; Iloprost - pharmacology; Myometrium - drug effects; Myometrium - physiology; Pregnancy; Pregnancy. Parturition. Lactation; Prostaglandin D2 - pharmacology; Prostaglandin Endoperoxides, Synthetic - pharmacology; Prostaglandins - pharmacology; Rats; Rats, Inbred Strains; Uterine Contraction - drug effects; Vertebrates: reproduction; Myometrium; Prostaglandin; Rat; Arachidonic acid derivatives; Rodentia; Contractility; In vitro; Pregnancy; Vertebrata; Mammalia; Uterus; Female genital system; Prostanoid; Thromboxane
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod46.3.392

The objectives of this study were to determine the effects of pregnancy in the rat on the contractile response of the myometrium
in vitro to a number of prostanoids. Longitudinally and circularly oriented strips were studied separately. Responses to PG
(prostaglandin)F2 alpha, PDG2, the PGI2-mimetic iloprost, and the thromboxane (Tx) A2-mimetic U-46619 were investigated on
Days 10, 15, 18, 20, 21, and 22 of pregnancy. Responses were prostanoid-dependent, and differences between longitudinal and
circular strips were small. PGF2 alpha and PGD2 produced similar patterns, with a high potency but low maximal response on
Day 10; thereafter potency fell to a minimum value on Day 18 and then gradually increased until Day 22, when it was still
lower than at Day 10. In contrast, for PGE2 there were no changes in potency over the period of study (longitudinal muscle)
or a slight increase between Days 15 and 21 (circular muscle). Both iloprost and U-46619 maintained a low potency throughout
pregnancy. We conclude that the pregnant rat's myometrium is probably not a target for PGI2 or TxA2 and that the difference
patterns of responses to PGE2 and PGF2 alpha during pregnancy support the hypotheses that these prostanoids act at different
sites within the myometrium.