The effect of inhibitors on insulin regulation of hormone secretion by cultured human trophoblast.

The effect of insulin in physiological concentrations on hormone secretion by human term trophoblast cell culture was studied in relation to insulin control of glucose transport and utilization. Specific inhibitors to these 2 functions were added to the culture, either alone to test for a dose response or with insulin. 2-Deoxy-D-glucose, which inhibits glycolysis, did not change the pattern of response of estradiol and placental lactogen (hPL) secretion to insulin. Phloridzin, an inhibitor of glucose transport, interfered with the stimulatory effect of insulin on hPL secretion, but stimulated insulin inhibition of estradiol secretion when added by itself. The results indicate that hPL response to insulin is dependent on glucose transport, but is independent of glycolysis. Estradiol response is dependent on glucose transport, but is independent of glycolysis.