Effect of maternal pituitary-adrenal axis on serum alphafetoprotein levels in pregnant rats.

The effect of the maternal pituitary-adrenal axis on alphafetoprotein (AFP) production was studied in pregnant rats. Serum AFP levels in the intact pregnant rats were raised significantly after day 12, reaching the maximum levels on day 21. There was a direct relation between the number of conceptuses and the maternal serum AFP levels. Hypophysectomy (HYPOX) on day 12 induced a significant raising of the maternal serum AFP levels on days 17 and 19. This increase was inhibited by daily injection of 10 U ACTH between days 12 and 17. In the rats which received adrenalectomy (ADX) on day 12 of pregnancy, the maternal serum AFP levels were significantly higher than the control group. These results suggested that the maternal pituitary-adrenal axis would inhibit AFP production by the fetus in pregnant rats.