Changes in Fat Tissue and Growth Hormone Receptor mRNA after Growth Hormone Therapy

ABSTRACT

PURPOSE: Growth hormone(GH) is a powerful inhibitor of lipoprotein lipase and is known to decrease fat cell mass. The lipolytic effect has more pronounced influence on visceral fat than subcutaneous fat. The effects of GH therapy on GH receptor in fat tissue are not clear. We investigated the changes in fat tissue and GH receptor mRNA in adipose tissue with GH therapy. METHODS: Eight children with growth hormone deficiency(GHD) and 9 children with Prader-Willi syndrome(PWS) were studied. The children were treated with 0.6U/kg/week GH for 6 months. We compared fat distribution on CT scan before and after GH therapy. Abdominal fat biopsy was done in 6 children with GHD, 3 children with PWS and 3 controls before and after GH therapy. GH receptor expression by reverse transcription PCR was examined. RESULTS: In children with GHD, total, subcutaneous and visceral fat were decreased after GH therapy(P>0.05), but thigh muscle mass was increased from 6,165 to 7,689(P<0.05). In chidren with PWS, visceral fat was decreased from 7,613 to 5,022 in abdominal CT(P<0.05) and V/S ratio(visceral fat/subcutaneous fat) was decreased also from 0.37 to 0.23(P<0.05). The thigh muscle mass was increased from 6,358 to 7,175. The expressions of GH receptor mRNA were reduced in children with GHD and PWS. But it was not significant in children with PWS. CONCLUSION: In children with PWS, fat mass was reduced and muscle mass was increased after GH therapy. In children with GHD, muscle mass was increased significantly and fat mass was decreased insignificantly. We observed down regulation of GH receptor of adipose tissue in patients with GHD after GH therapy.