Influence of gestation and hydrocortisone-acetate treatment on the nutritive utilization of protein

The effect of pregnancy and of cortisol on the digestive and metabolic utilization of protein in Wistar rats was studied. The cortisol is i.m. administered during 21 days in a pharmacological dose (4 mg/100 g weight per day) to female Wistar rats. Pregnancy is observed to increase and cortisol to decrease significantly the food intake (g dry matter/rat per day); the intake of nitrogen follows the same pattern. Pregnancy significantly increases the weight of both groups: pregnant rats as comparison to non-pregnant rats saline injected and pregnant rats cortisol-treated in relation to the animals pregnant but not hormone-treated. The increase being greater in the last 5 days of pregnancy. Cortisol in the pregnant and non pregnant rats considerably reduces the weight. The protein absorption is unaltered by pregnancy but is diminished by the effect of cortisol. Pregnancy increases the balance of nitrogen in both sets of rats; the increase being significantly greater in the last period of pregnancy. When administered to non pregnant rats, cortisol produces a negative balance of nitrogen. The protein of good quality (casein + 5% DL-methionine at a level of 12%) partially equalizes the negative effect of cortisol in spite of the long treatment and high doses used.