VISCERAL ADIPOSE-TISSUE IS ASSOCIATED WITH CIRCULATING HIGH-AFFINITY GROWTH HORMONE-BINDING PROTEIN

Recent data show that body fat distribution, specifically visceral fat accumulation, is associated with the regulation of GH secretion. To o ur knowledge no studies have been performed with regard to the relatio nship between plasma high affinity GH-binding protein (GHBP) levels an d fat distribution in humans. To address this question, we measured pl asma GHBP and insulin-like growth factor I levels as well as visceral, sc abdominal, and hip adipose tissue (AT) areas by using magnetic res onance imaging scanning in 12 patients with GH deficiency (GHD) and in 12 age- and sex-matched healthy subjects. The GHD patients were subse quently treated with GH replacement therapy. Regardless of the GH stat us of the subjects, body mass index and visceral AT area were positive ly correlated to plasma GHBP (r = 0.70; P < 0.01 and r = 0.73; P < 0.0 1, respectively), whereas the sc AT areas at the abdominal level tende d to correlate positively with GHBP levels, but did not reach signific ance (r = 0.44; P = 0.07). The sc AT areas at the hip level were not c orrelated with plasma GHBP levels. In the GHD patients the pretreatmen t visceral and abdominal sc AT areas were positively correlated with t he change in GHBP levels after GH replacement (r = 0.82; P < 0.01 and r = 0.75; P < 0.01, respectively). The pretreatment sc AT area at the hip level was not associated with the therapy-induced changes in plasm a GHBP (r = 0.28; P > 0.10). In summary, this study shows that viscera l fat is associated with circulating GHBP levels, suggesting that visc eral fat mass may be involved in the regulation of the plasma GHBP lev el. Further, the amount of abdominal fat in GHD patients may partially determine the plasma GHBP response to GH replacement therapy.