Cardiovascular and metabolic responses to chronic PYY3‐36 infusion

Abstract

Peptide YY3‐36 (PYY3‐36) is secreted by the gastrointestinal tract in response to feeding and has been shown to have anorexic actions during acute systemic injections. The importance of PYY3‐36 in chronic regulation of food intake and cardiovascular function, however, is poorly understood. The purpose of the current study was to test the hypothesis that chronic infusion of PYY3‐36 leads to sustained reductions in food intake and elevations in blood pressure (BP) and heart rate (HR). Sprague Dawley rats (n=7) were instrumented with arterial and venous catheters for continuous monitoring of BP and HR. After recovery and 5 days of control measurements, PYY3‐36 was infused IV for 7 days at a dose of 10 nM/hr. Post‐control measurements were taken for 5 additional days. PYY3‐36 infusion caused a sustained 20% reduction in caloric intake after day 3 (82 ± 2 kcal to 65 ± 2 kcal). BP remained unchanged during PYY3‐36 infusion (+2.8 ± 0.1 mmHg, average change on days 5‐7 of infusion), whereas HR increased significantly (20 ± 1 bpm). Food intake returned to control level within one day after stopping PYY3‐36 infusion. Heart rate, however, did not return to control values until the 2nd day following the termination of PYY3‐36 infusion. Our results indicate that chronic PYY3‐36 infusion caused a sustained reduction in appetite while increasing HR but had no significant effect on chronic blood pressure regulation. (NHLBI ‐ PO1 HL51971).