Comparison of immunoreactive gonadotropin-releasing hormone and human chorionic gonadotropin in term placentas from normal women and those with insulin-dependent and gestational diabetes.

We measured prohormone gonadotropin-releasing hormone (high-molecular-weight gonadotropin-releasing hormone), gonadotropin-releasing hormone and human chorionic gonadotropin concentrations in term placentas from normal women and those with insulin-dependent and gestational diabetes. The placental immunoreactive gonadotropin-releasing hormone levels were significantly higher in normal tissues than in tissues from insulin-dependent and gestational diabetes (p less than 0.01). When compared with diabetic placental extracts, normal tissue also had more stored prohormone immunoreactive gonadotropin-releasing hormone. Whereas there were no consistent differences in placental human chorionic gonadotropin concentrations in normal tissues and tissues from insulin-dependent and gestational diabetes, there was a significant correlation between gonadotropin-releasing hormone and human chorionic gonadotropin concentrations in normal samples (r = 0.57, p less than 0.05), which was abolished when the diabetic tissue was included in the analysis. These data suggest that differences in high-molecular-weight gonadotropin-releasing hormone and gonadotropin-releasing hormone concentrations in term placentas from normal versus diabetic mothers may be due to enhanced processing of the prohormone and increased release of the decapeptide in diabetic pregnancy.