Fig. 4. ak mice show deficits of gastrointestinal function. Four- to six-month-old male rd1 and ak mice underwent (A) charcoal evacuation tests, showing that ak mice have longer whole gut transit time than wt and rd1 mice; (B) bead expulsion tests showing that ak mice have colon motility deficits compared with wt and rd1 mice. Quantitative real time PCR showed that expression levels of certain inflammatory markers, IL-6 and IFN-γ, but not of IL-1β, are higher in ak mouse colon (C) than in wt and rd1 mice. In the stomach, none of the three markers showed significant differences between ak and wt and rd1 mice (D). *p < 0.05; **p < 0.01; Mean ± S.E.M.,  n  = 6–10 for each group. N.S. = no significant difference.