P-140. Fitness is related to 24-h GH release in older men but not women

24-h GH release is correlated with visceral adipose tissue (VAT) in older men and women (ICE 1996 #OR3-4). To determine the relationship among aerobic fitness, VAT and GH release in older adults, serum GH was measured (chemiluminescence assay) at 5-min internals for 24 h in 17 older and 14 women (67±0.9 [SE] yr); 24-h integrated [GH] (IGHC) was calculated. Peak oxygen consumption (VO₂ peak, n = 31) and VO₂ at the lactate threshold (VO₂ LT, n = 19) were measured during an incremental treadmill test. VAT area was measured by CT at the L4-L5 space. Men had higher values (vs women, ml-kg^-1-min^-1) for VO₂ peak (32.5±1.1 vs 22.8±1.2, p<0.01) and VO₂ LT (21.1±1.2 vs 15.1±0.3, p<0.01). Men tended to have lower IGHC than women (664±87 vs 913±110 min μg-L^-1, p = 0.08) but VAT area did not differ (123±13 vs 112±11 cm²). IGHC was correlated with VO₂ peak and VO₂ LT in men (r = 0.51, p = 0.04; r = 0.77, p<0.01) but not in women (r = 0.21; r = 0.08). VAT was correlated with VO₂ peak and VO₂ LT in men (r = 0.77, p<0.01; r = 62. p = 0.07) but not women (r = 0.35, r = 0.34). In contrast, IGHC was correlated with VAT in both men (r=0.75, p<0.01) and women (r = 0.59, P = 0.03). We conclude that in older men aerobic fitness is related to both 24-h GH release and VAT; fitness may influence GH secretion directly or by reducing VAT. In older women. 24-h GH release is related to VAT but not to aerobic fitness; fitness has less impact on VAT.