Fig. 1.

Morphology and a cell proliferation marker in the intestines of fed, fasted, and refed X. laevis. A Histology of representative intestines of fed, fasted, and refed X. laevis stained with hematoxylin and eosin. The frogs were fed for 22 days (a), fasted for 22 days (b), or fasted for 21 days and then refed for 1 day (c), and fasting for 5 months (d). e Schematically illustrated structure of the X. laevis intestine with morphological parameters measured (see Table 1). The box in each panels (a–d) is enlarged image. el epitherial layer, gc goblet cell, lu lumen, me muscularis externa, tr trough, vi villus. Bar 500 μm in panels a, b, c and d, and 100 μm in boxes. These experiments were repeated at least three times, with similar results. B Protein expression of proliferating cell nuclear antigen (PCNA) in the intestines from fed, fasted, and refed X. laevis. Intestine homogenates (60 μg protein; two samples/each group) were analyzed by SDS-PAGE, followed by Western blotting. Band intensities were analyzed and expressed relative to α-tubulin, and values are expressed relative to the value of the fed frog (left) that was set to 1.00. (a) PCNA; (b) α-tubulin