Response of fat cells to growth hormone (GH): effect of long term treatment with recombinant human GH in GH-deficient adults.

GH deficiency impairs lipid metabolism in adults, but little is known about the direct effect of GH on adipose tissue in humans. First, the in vitro response of fat cells to GH in five GH-deficient adults was studied; second, it was investigated whether 6-month recombinant human GH (rhGH) administration modifies this response. Biopsies of fat were obtained from the periumbilical region before and after rhGH administration. The response of the collagenase-isolated fat cells to various concentrations of GH was assessed by glycerol release, measured by bioluminescence. Before treatment, GH induced a lipolytic activity from the adipocytes, which became significantly higher after 6 months of treatment. Thus, this study provides evidence for an intrinsic lipolytic activity of GH in GH-deficient adults and for its improvement after long term rhGH administration.