Enhanced exercise-induced GH secretion in subjects with pro7 substitution in the Prepro-NPY

The leucine 7 to proline 7 (Leu7Pro) polymorphism in the signal peptide of NPY is associated with high blood lipid concentrations and accelerated rate of atherosclerosis as well as diabetic retinopathy. Also, healthy subjects with this polymorphism have increased NPY secretion during sympathetic sti mulation. Because NPY may regulate GH release and ghrelin may regulate NPY formation, we studied the effects of the Leu7/Pro7 genotype on GH, ghrelin, and IGF-I secretion during standardized cycle-ergometer exercise. Furtherm ore, we studied the effect of the Leu7/Pro7 genotype on diurnal GH secretio n in rest in a separate study. The subjects with Leu7/Pro? genotype had 54% higher maximal increases in the plasma GH concentrations than the controls during exercise. There were no significant differences in the ghrelin or I GF-I concentrations during exercise among the groups. Furthermore, there we re no differences in diurnal GH secretion between the genotypes. The result s indicate that the prepro-NPY genotype has an influence on GH response dur ing exercise in humans. The clinical significance of this finding is not kn own, and further studies are needed to evaluate whether the observed change in GH secretion during exercise could play a role in promoting diseases.