Effects of human growth hormone on lipid metabolism in hypophysectomized rats

Abstract

Growth hormone (GH) replacement therapy has been proved to show beneficial effects on abnormalities of lipid metabolism in adult growth hormone deficiency (GHD) patients. To support this clinical evidence, we studied the effects of recombinant human growth hormone (rhGH) in combination with L-thyroxine (T4) 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 findings in adult GHD patients. At para-physiological doses, replacement therapy with rhGH, T4 and CS in HPX rats restored the increased body fat and LDL-cholesterol levels to normal. But replacement therapy with T4 only, or both of T4 and CS did not show clear effects. These results support that rhGH has an important role in maintaining lipid metabolism, providing with a rationale for the effectiveness of rhGH replacement therapy on normalizing impaired lipid metabolism in adult GHD patients.