Effects of human growth hormone on lipid metabolism in hypophysectomized rats

Growth hormone (GH) replacement therapy has been proved to show beneficial effects on abnormalities of lipid metabolism in adult growth hormone defici ency (GHD) patients. To support this clinical evidence, we studied the effe cts of recombinant human growth hormone (rhGH) in combination with L-thyrox ine (T-4) and corticosterone (CS) on lipid metabolism in hypophysectomized (HPX) mature rats. Hypophysectomy resulted in marked increases of body fat and serum low density lipoprotein (LDL)-cholesterol similarly to the findin gs in adult GHD patients. At para-physiological doses, replacement therapy with rhGH, T-4 and CS in HPX rats restored the increased body fat and LDL-c holesterol levels to normal. But replacement therapy with T-4 only, or both of T-4 and CS did not show clear effects. These results support that rhGH has an important role in maintaining lipid metabolism, providing with a rat ionale for the effectiveness of rhGH replacement therapy on normalizing imp aired lipid metabolism in adult GHD patients.