Effect of whey protein metabolites on insulin signaling in women with polycystic ovary syndrome (PCOS)
The purpose of this project was to examine the impact of whey protein (WP) ingestion on insulin sensitivity in women with and without polycystic ovarian syndrome (PCOS). Women with PCOS tend to have insulin resistance (IR), characterized by disrupted cell insulin binding resulting in reduced cellular glucose uptake. This faulty insulin response leads to high blood glucose levels. PCOS and non-PCOS women were administered oral glucose tests (OGTT) on Day 0 (baseline), Day 1 (start of WP treatment) and Day 7 (post-initiation of WP intake). Plasma insulin and glucose were measured. No significant difference in glucose responses for Day 0 and 1 was observed. Contrasting Day 0 to Day 1, insulin levels between the PCOS and non-PCOS women were significantly higher at 30 min after the start of WP treatment in the PCOS group and after 15 min and 90 min in the non-PCOS group. At Day 7, Non-PCOS insulin spiked at 15 min where PCOS women had a bimodal insulin response with peaks at 30 and 120 min. To further understand changes in insulin in PCOS vs. non-PCOS women before and after WP treatment, differentiated 3T3-L1 mouse adipocytes were treated with the human plasma collected during OGTTs for 48 hrs with media and cells were collected for protein and gene expression analysis. GLUT-4 expression was higher with 7th day plasma incubation in the non-PCOS women compared to Day 0 and to the PCOS woman at any time point. All GLUT-4 levels were elevated above the positive control cultures. While preliminary data identified minimal effects of whey protein supplementation on IR in PCOS women, acute WP treatment reduced peak glucose responses by enhancing insulin release in women with and without PCOS following glucose load.