Hypothalamic thyrotropin-releasing hormone and maternal plasma TRH-peptidase activity in protein-deficient and food-restricted pregnant rats and their fetuses.

This study examined the effects of protein deficiency and food restriction on hypothalamic TRH in pregnant rats and their fetuses. The absolute and relative amounts of TRH in hypothalami were not significantly changed by diet in either dams or fetuses. Plasma TRH-peptidase activity in the dam was significantly reduced by protein deprivation, whereas food restriction caused a lesser reduction. Fetal hypothalamic TRH was less affected by maternal malnutrition than was fetal body size.