Insulin and glucose effects on amino acid metabolism in pregnant and nonpregnant ewes.

The effects of 1) a rapid intravenous injection of insulin (4.4 IU), 2) a continuous intravenous infusion of insulin (.14 IU/min), or 3) a rapid intravenous injection of glucose (.24 g/kg body weight) into nonpregnant ewes and 4) a continuous intravenous infusion of glucose (1.2 mg/kg body weight/rain) into pregnant ewes on plasma amino acid metabolism and a-amino acid nitrogen (~-NH 2 -N) uptake by the gravid uterus were studied in four experiments. A continuous infusion or a rapid injection of insulin into nonpregnant ewes did no t significantly alter total plasma free 0t-NH2-N or plasma urea-N concentrations. Plasma glucose concentrations decreased to about 50% Gf control levels with both continuous and rapid insulin infusions. However, total plasma free a-NH2-N decreased with a rapid injection of glucose into nonpregnant ewes and a continuOus infusion of glucose into pregnant ewes. Concentrations of lysine, arginine, threonine, leucine, and tyrosine decreased most markedly (about 35%) after rapid glucose injection. Continuous glucose infusion into pregnant ewes did not markedly alter blood flow to or a-NH2-N uptake by the gravid uterus .