Impact of Menstrual Phase on Oral Glucose Sensitivity

In this study we are determining whether the hormones associated with the phases of the menstrual cycle (menstruation \& ovulation) influence taste sensitivity to glucose. We hypothesized that women would be more sensitive to oral glucose as assessed by absolute detection threshold during ovulation than when assessed during menstruation. These phases of the cycle are associated with peak plasma estradiol levels and nadir estradiol levels. There is evidence that estrogen can increase the sensitivity of the metabolic signaling pathway of the pancreatic beta-islet cells to stimulate insulin release more readily when glucose is present by increasing sensitivity of the K-ATP channel to ATP. Since the same metabolic signaling pathway is reported to be present in taste tissue, we tested whether peak estrogen levels would enhance taste detection of glucose but not sweeteners that cannot generate ATP, such as sucralose or methyl-D-glucopyranoside (MDG).