Characterizing the appetite‐regulatory response throughout the menstrual cycle
Authors: McKie Greg L. , Townsend Logan K. , Islam Hashim , Medeiros Phil , Gurd Brendon J. , Hazell Tom J. 
Published: June 2021

BackgroundObesity rates are higher among females than males potentially due to increases in food intake during certain phases of the menstrual cycle. The female sex hormones, progesterone (P4) and estradiol (E2), fluctuate across the menstrual cycle and are known to influence both energy intake and energy expenditure. Physiologically, the control of energy intake is partially mediated by circulating gut‐derived peptides that either stimulate appetite (acylated ghrelin (AG)) or induce satiety (PYY3–36 and GLP‐1). However, it remains poorly understood how the fluctuations in E2 and P4 influence appetite throughout the menstrual cycle via interactions with gut‐derived peptides, and whether these fluctuations in sex hormones also influence metabolic rate and substrate oxidation.PurposeTo examine changes in appetite regulating hormones, appetite perceptions, metabolic rate, and substrate oxidation during the follicular (FP), ovulatory (OP), and luteal (LP) phases of the menstrual cycle. We hypothesized that the LP, with increased P4, would be associated with greater concentrations of AG, low GLP‐1 and PYY3–36, and greater perceived hunger. Conversely, during the OP, with high concentrations of E2, there would be lower AG but greater concentrations of GLP‐1 and PYY3–36 with concomitantly diminished perceived hunger.MethodsNine healthy young females (age: 22.3±4.5 y; BMI: 23.91±3.52 kg·m−2) were studied during the FP, OP, and LP phases. Venous blood samples were collected following a 12 h overnight fast, and at 30, 60, and 90 min following a standardized test meal (29 kJ·kg−1 bw) to test for E2, P4, AG, PYY3–36, and GLP‐1. Perceptions of appetite were measured immediately prior to each blood sample using visual analogue scales. Fasted gas exchange was measured via indirect calorimetry to assess resting metabolic rate and substrate oxidation.ResultsFasting plasma E2 and P4 concentrations confirmed proper timing of experimental sessions. Post‐prandially there were main effects of time for AG (P=0.039) and GLP‐1 (P<0.001), but not PYY3–36. Menstrual phase had no effect on fasting or post‐prandial plasma concentrations of AG or GLP‐1 (P>0.05), but the post‐prandial change in PYY3–36 was lower during the LP compared to the FP (P=0.026) and OP (P=0.007). P4 concentrations correlated strongly with fasting AG concentrations in the LP only (r=0.93, P=0.024), while E2 correlated strongly with fasting GLP‐1 in the LP only (r=0.90, P=0.036). Fullness and satisfaction both increased over time (P<0.001) and were greater during the OP compared to the FP and LP (P<0.05). There was no effect of menstrual cycle phase on resting metabolic rate (P=0.388), carbohydrate oxidation rate (P=0.603), or fat oxidation rate (P=0.534).ConclusionThese results confirm that fluctuations in female sex hormones are associated with distinct hormonal and perceptual responses to feeding throughout the menstrual cycle.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.