Direct effect of human growth hormone to inhibit glucose uptake in cultured human fibroblasts.

We have examined the effect of human growth hormone (HGH) on both basal and insulin stimulated glucose uptake in human fibroblasts. High concentrations of HGH (100 micrograms/mL) depressed both basal and insulin-stimulated glucose uptake by 25%. Significant inhibition was not seen at concentrations below 50 micrograms/mL of HGH. HGH-related hormones like human prolactin and ovine growth hormone had no effect on glucose uptake while high concentrations of ovine prolactin reduced basal glucose uptake, albeit to a lesser degree than HGH. In conclusion, high concentrations of HGH act independently of insulin to inhibit glucose uptake in human fibroblasts. These data may help explain the glucose imbalance and insulin resistance that is characteristic of acromegaly.