P-088. abdominal adiposity rather than age and sex predicts the mass and patterned regularity of gh secretion in healthy adults

We tested whether abdominal adiposity; accounts for the variation in endogenous GH secretion in 42 non-fasting, clinically non-obese adults of different age and sex (mean BMI (SE) 24 (0.5) kg/m²). We measured lean and fat tissue distribution (CT and DNA), and physical fitness (VO₂-max), and deconvolution analysis was used to estimate specific features of 24-h GH secretion and clearance. Approximate entropy was used to quantify the orderliness or regularity of the GH release process. Older subjects exhibited reduced (1) mean GH concentrations, (2) GH production rate, (3) amplitude, and (4) mass of GH secreted per burst compared to younger individuals. Females had a higher (1) mean 24-h GH secretion, (2) GH production rate, (3) amplitude, and (4) mass of GH secreted per burst, and (5) a longer GH half-life than males. No differences in number of GH secretory bursts were found between either groups. Females displayed significantly more irregularity in their GH release profiles than males. Mean 24-h serum GH concentrations correlated inversely with intra-abdominal fat and W/H-ratio and positively with VO₂-max. Multiple linear regression analysis revealed that intra-abdominal fat and W/H ratio were the major determinants of mean 24-h serum GH concentration, endogenous GH production rate, amplitude and mass of GH secreted per burst. We conclude that intra-abdominal fat is a dominant determinant of GH secretion in healthy, non-obese adults. Although the underlying mechanisms remain to be elucidated, our findings extend the clinical implications of visceral adiposity to include hyposomatotropism.