Peptide YY is secreted after oral glucose administration in a gender-specific manner

Context: Previous studies with small numbers of subjects showed a negative correlation between plasma peptide YY ( PYY) levels and obesity. If correct, this would imply that low PYY levels might be involved in the pathogenesis of obesity. Objective: Our objective was to investigate whether plasma PYY levels were correlated with sex and body mass index ( BMI). Design, Setting, and Patients: We conducted a cross-sectional study of 151 normal volunteers ( 19-90 yr of age) in the Baltimore Longitudinal Study of Aging. Interventions: All subjects had an oral glucose tolerance test ( 75 g) performed. Main Outcome Measures: Immunostaining of human duodenum, BMI, hemoglobin A(1c), plasma glucose, insulin, PYY, glucagon like peptide-1 (GLP-1), ghrelin, and leptin were the main outcome measures. Results: PYY and GLP-1 colocalized in the same cells in human duodenum. Both hormones reached peak plasma levels by 20 min and had similar secretory patterns. The incremental increases in PYY and GLP-1 during that first 20 min were significantly correlated ( r(2) = 0.388; P < 0.0001). The areas under the curve from 0-120 min for PYY and GLP-1 were similar in both obese and lean participants. Female participants across the range of BMI had significantly higher PYY area under the curve ( 17,464 +/- 1,240 vs. 14,120 +/- 806 pmol/ liter center dot min, female vs. male; P < 0.05) compared with male participants. Conclusions: Our findings show that PYY and GLP-1 are colocalized and cosecreted from L cells and that total secretion of PYY is higher in females than in males, but fasting PYY levels and PYY secretion in response to oral glucose were not in any way correlated with BMI.