Lung surfactant in the hyperinsulinemic fetal monkey

Abstract

We examined the effect of hyperinsulinemia in the absence of hyperglycemia on parameters of lung surfactant production in the fetal rhesus monkey at 134–148 days gestation. Hyperinsulinemia was achieved by infusion of insulin for 21 d from an Alzet minipump implanted in the fetal hind leg. Blood insulin levels were elevated 80-fold in the treated group. These fetuses were also slightly hypoglycemic and their body weights were 25% greater than expected. There were no differences, however, between the insulin-treated and control groups in the phospholipid content and composition of lung lavage or lavaged lung tissue or in the rate of choline incorporation into disaturated phosphatidylcholine in lung slices. These data suggest that hyperinsulinemiaper se does not inhibit surfactant production in the fetal primate at least up to 148 d gestation. Although an inhibitory effect of insulin later in gestation is not ruled out, it is also possible that hyperglycemia rather than hyperinsulinemia is responsible for the deficiency in surfactant often observed in human infants of diabetic mothers.