Growth hormone increases beta-cell proliferation in transplanted human and fetal rat islets.

OBJECTIVE The aim of the study was to increase the number of human islet beta-cells after transplantation with injections of human growth hormone (hGH). INTERVENTIONS Human islets and fetal rat islets were transplanted under the left kidney capsule and under the right kidney capsule, respectively in nude normoglycemic mice which were then given a daily injection of 200 microg hGH for 1-4 weeks. MAIN OUTCOME MEASURE Beta-cell proliferation was determined using thymidine incorporation and the beta-cell area was assessed using light microscopy. RESULTS Mice given hGH increased their body weight one week after transplantation and had a more efficient removal of glucose after 3 and 4 weeks. Treatment with hGH resulted in increased beta-cell proliferation in human and fetal rat beta-cells, and the beta-cell area tended to increase. However, serum insulin concentrations and pancreas insulin content remained unchanged. CONCLUSIONS hGH increased the proliferation of transplanted human beta-cells as well as improving the glucose tolerance of the transplanted mice.