Fig. 1

Blood estrogen decreases after meals, especially after carbohydrate intake in males. Eight-week-old male rats were deprived of food for 12 h. a Rats were fed either a high-fat diet (HFD, red) or a normal diet (ND, blue) ad libitum for 30 min (from −0.5 to 0 h, bars). Blood triglyceride (TG), fatty acids (FFA), glucose, and estrogen (E2) levels in the tail vein were measured before (−0.5) and at 0, 1, 2, 3, 4, and 5 h after feeding. Rats fed HFD were allowed a week to adapt to the diet before the experiment. b and c Rats were orally administrated either carbohydrate (4 g starch per kg of body weight, blue), TG (2.5 mL olive oil per kg of body weight, red), or protein (2 g casein per kg of body weight, green) using intragastric gavage technique. Blood TG, FFA, glucose, and E2 levels in the tail vein were measured before (0) and at 1, 2, 3, 4, and 5 h after administration (b). Correlation diagram between blood FFA and E2 levels of carbohydrate-administered rats at 1 h after administration (c). d Rats were fed ND ad libitum for 30 min. Blood TG, FFA, glucose, and E2 levels in the tail vein and blood E2 levels in the portal vein were measured 2 h after feeding (blue). Fasted rats were used as control “pre-fed” rats (brown). Data are represented as mean ± s.d. n = 8. a, b, d P values were determined by a two-sided Student’s t-test between the indicated data sets. c, R and P values determined by Pearson’s product-moment correlation with a 95% density ellipse. Raw data are provided in Supplementary Data 1.