GUT REGULATORY PEPTIDE LEVELS IN BOVINE FETUSES AND THEIR DAMS BETWEEN THE 3RD AND 9TH MONTHS OF GESTATION

Several gut regulatory peptides were measured by radioimmunoassay betw een 3 and 9 months of gestation in the plasma of 91 bovine fetuses and their dams, in fetal gastric content and in amniotic fluid. During ge station, plasma peptide concentrations did not change in cows. Likewis e, fetal plasma concentrations of cholecystokinin, somatostatin, secre tin and vasoactive intestinal polypeptide showed no variation while th ose of gastrin, pancreatic polypeptide and gastric inhibitory polypept ide increased during the last 6 months. Peptide levels in the fetus we re higher than or equal to maternal concentrations. At 8-9 months of g estation, gastrin, CCK, secretin and somatostatin concentrations in am niotic fluid were lower than those measured in fetal gastric content a nd in maternal and fetal plasma. Therefore, a substantial endogenous e ndocrine production of regulatory peptides by the fetus probably exist s as early as the third month of gestation, accompanied by a release i nto the lumen of the gut.