Urinary phenolsulfonphthalein (PSP, A) and Cr-EDTA (B and C) excretion for 48 h after administration of their oral loads in the OLETF and LETO rats fed the standard and high fat diets. The intestinal permeability tests were performed at 3 (A), 9 (B), and 15 (C) weeks after the start of feeding the experimental diets. Each value represents mean ± SEM, n = 9. Means without a common letter differ, P < 0.05. P values estimated by 2 way ANOVA were (A) 0.24 for strain, < 0.01 for diet, and 0.67 for strain × diet, (B) 0.04 for strain, < 0.01 for diet, and 0.79 for strain × diet, and (C) 0.79 for strain, <0.01 for diet, and 0.16 for strain × diet.