Biology of Reproduction, Vol 14, 143-150, Copyright © 1976 by Society for the Study of Reproduction

Effect of Dietary Protein Restriction on Hormone Status and Embryo Survival in the Pregnant Rat

¹ Department of Food Science, Clemson University, Clemson, South Carolina 29631

One hundred and sixty-two pregnant rats were allocated to either of three factorial experiments. These experiments were conducted to examine the effects of dietary protein (0, 6, and 18 percent of diet) on plasma prolactin and progesterone levels, the weights of the corpora lutea, ovary and fetus, and the number of implantation sites. In the first experiment rats were killed after mid-pregnancy (Days 10, 12 and 14) and in the second and third experiment rats were killed before mid-pregnancy (Days 8 and 10). On Days 8 and 10, plasma prolactin was significantly less (P<.01) in the fully deprived rats than in the fully fed rats. The mean plasma progesterone level was also significantly lower in the protein deprived rats on Days 8 and 10 of pregnancy (P<.01) and this effect on plasma progesterone became greater in rats killed later in pregnancy (Days 12 and 14). In the experiment in which rats were killed on Day 8 only, there was only a trend toward lower progesterone levels in the protein deprived group compared with the fully fed group (P<.05). The effect of dietary protein level on maternal organ weights, fetal weights and number of implantations was readily apparent after mid-pregnancy but not before mid-pregnancy. The marginal dietary protein level (6 percent) had little if any effect on the parameters measured in rats killed before or after mid-pregnancy.

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ACKNOWLEDGMENTS We are indebted to Drs. J. D. Neill and I. H. Thorneycroft for their aid in completing this study.