The current study was undertaken to determine the effects of porcine growth hormone (pGH) administration on insulin binding to swine liver microsomes. Liver microsomes were prepared from pigs, injected with either pGH (22ug/Kg BW) or bicarbonate buffer for 30 days. Insulin binding was measured by incubating 250ug of microsomes protein with I^(125)-insulin and various concentrations of unlabeled insulin in 50 mM Tris buffer for 24h at 4℃. Porcine GH administration had no effects of insulin binding to liver microsomes with a decrease in receptor concentration and a compensatory increase in receptor affinity. These findings suggest that GH induces insulin resistance at post-receptor levels.