Inhibition of prostaglandin synthesis by ovine allantoic fluid: acute reduction in inhibitory activity during late gestation.
The capacity of ovine allantoic fluid to modulate prostaglandin (PG) synthesis was measured in fluid taken from ewes at 100-140 days gestation. An inhibitor of PG synthesis was found in allantoic fluid from ewes at 100-130 days gestation. The inhibitor had the capacity to inhibit PGF2 alpha, PGE2, and 6-keto-PGF1 alpha synthesis by endometrial cotyledon microsomes in a concentration-dependent manner. At 140 days gestation, the inhibitory potency of the fluid was significantly less than that present at 100-130 days gestation, at concentrations greater than 20% (v/v) (p less than 0.001). The inhibitor is not albumin and remained active after boiling, dialysis, and protease treatment. It was extracted with chloroform-methanol, indicating that the active portion of the molecule is a lipid. We suggest that parturition in the sheep may be associated with a local withdrawal of inhibition of prostaglandin synthesis.
D000482:Allantois / Q000032:analysis / Q000502:physiology*; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D005321:Extraembryonic Membranes / Q000502:physiology*; D005260:Female; D008297:Male; D010447:Peptide Hydrolases / Q000494:pharmacology; D011247:Pregnancy; D011448:Prostaglandin Antagonists / Q000502:physiology*; D011453:Prostaglandins / Q000096:biosynthesis*; D012756:Sheep
D001095:Arachidonic Acids; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; D016718:Arachidonic Acid; D010447:Peptide Hydrolases; D002118:Calcium