The effects of growth hormone treatment of thyroid-deficient pregnant rats on maternal and fetal carbohydrate metabolism.

Maternal hypothyroidism in rats has been shown previously to result in alterations of maternal, placental, and fetal metabolism. Maternal treatment with 2 IU GH/day for three days prior to autopsy (on the 22nd day of pregnancy) corrected many of the observed alterations of carbohydrate metabolism in hypothyroidism. The maternal and fetal liver glycogen concentrations and the fetal serum glucose levels of the hypothyroid animals were elevated significantly by the GH treatment. In most cases, the utilization of a [1-14C]glucose tracer dose was returned to normal by GH treatment. These results suggest that the impairment of fetal metabolism occurring in maternal hypothyroidism may be due in part to insufficient maternal GH secretion. However, GH alone in the absence of sufficient thyroid hormones did not totally correct all of the observed fetal abnormalities.