The effect of GH replacement therapy on different fat compartments: a whole-body magnetic resonance imaging study

Abstract

ObjectivePatients with GH deficiency (GHD) are insulin resistant with an increase in visceral fat mass (FM). Whether this holds true when sedentary control subjects (CS) are matched for waist has not been documented.GH replacement therapy (GHRT) results in a decrease in FM. Whether the decrease in FM is mainly related to a reduction in visceral FM remains to be proven. The aim was to separately assess visceral and subcutaneous FM in relation to insulin resistance (IR) in GHD patients before and after GHRT and in sedentary CS.MethodsTen patients with GHD were investigated before and 6 months after GHRT. Sedentary CS matched for age, gender, body mass index, and waist were assessed. Exercise capacity was measured as VO2maxusing an incremental work load on a treadmill. Visceral and subcutaneous FM were measured using whole-body magnetic resonance imaging and IR by the homeostasis model assessment of IR (HOMA-IR) index.ResultsGHD patients had a non-significantly lower VO2maxbut did not have increased subcutaneous and visceral FM compared with CS. GHRT resulted in a similar relative decrease in subcutaneous and visceral FM. Compared with CS, GHD patients showed a lower HOMA-IR. GHRT tended to increase HOMA-IR.ConclusionMatching for waist and separate assessment of visceral and subcutaneous FM may be critical in the evaluation of body composition and IR in GHD patients before and after GHRT.