Peptide YY Levels across Pubertal Stages and Associations with Growth Hormone

Abstract

Changes in appetite-regulating peptides may impact food intake during puberty and facilitate the pubertal growth spurt. Peptide YY (PYY) is an anorexigenic hormone that is high in anorexia nervosa and low in obesity, inhibits GnRH secretion, and is suppressed by GH administration. The relationship between PYY and GH has not been examined across puberty. We hypothesized that PYY would be inversely associated with GH in adolescents and would be lowest when GH is highest. We conducted a cross-sectional study at a Clinical Research Center. We studied 87 children, 46 boys and 41 girls ages 9-17 yr at Tanner stages 1-5 of puberty (10th-90th percentiles for body mass index). We measured fasting PYY and nadir GH levels after administration of an oral glucose load. Leptin levels were also measured. Fasting PYY was lowest and nadir GH highest in boys in Tanner stages 3-4 (P = 0.02) and in girls in Tanner stages 2-3 (P = 0.02). Leptin levels were highest in early pubertal boys and late pubertal girls. For the group as a whole and within genders, even after controlling for body mass index, log nadir GH correlated inversely with log PYY (P = 0.003, 0.07, and 0.02). PYY levels did not correlate with leptin levels. During mid-puberty, at a time when GH levels are the highest, PYY is at a nadir, and these low PYY levels may facilitate pubertal progression and growth.