Fig. 2

Intravenous injection of lipids partially recovers postprandially decreased blood estrogen levels in males. a Male rats aged 11–15 weeks were deprived of food for 4 h. Isolated gastric gland epithelia from the rats (left) were incubated with capric acid (C10-FFA: 0, 250, 500 and 1000 µM) in the presence of testosterone (20 nM) at 37 ^◦C for 1 h. Relative total E2 levels compared to the non-E2 producing control (C10-FFA: 0 µM) were determined (middle), and the relationship between C10-FFA concentrations and relative total E2 levels was analyzed (right). Bar: 50 μm. b and c Eight-week-old male rats were deprived of food for 12 h before the experiment. TG (2 mL of 20% soy oil emulsion per kg of body weight, b) or C10-FFA (2 mL of 150 mM capric acid [pH 7.8] per kg of body weight, c) was injected intravenously into postprandial rats (2 h after a 0.5 h ND feeding [bars]) (ND + TG or C10-FFA iv, blue) or control fasted rats (fasted + TG or C10-FFA iv, brown) (arrows, at 0 h). Blood TG, FFA, and E2 levels in the tail vein were measured before (ND-fed: at −2.5, −2, −1, 0 h; fasted: at 0 h) and at 0.25, 0.5. 1, 2, 3 h after injection. d Changes in blood FFA and E2 levels in fasted (brown) and postprandial (ND, blue) rats from before (at 0 h) to 0.25 h after the injection of TG or C10-FFA. Data are represented as mean ± s.d. n = 8. a R and P values determined by Pearson’s product-moment correlation with a 95% density ellipse. b–d P values were determined by a two-sided Student’s t-test between the indicated data sets. Raw data are provided in Supplementary Data 2.