Fig. 1.

Age-related changes in the ERG. (A) Average ERGs recorded from a group of moderately hypoglycemic Gcgr^−/− mice (red traces; n = 3) and euglycemic Gcgr^+/− mice (black traces; n = 4) in response to 10-ms flashes. (B) Intensity-response functions of a-waves recorded from moderately hypoglycemic Gcgr^−/− mice ages ≤8 to 13 months. (C) Intensity-response functions of b-waves from the same ERGs that yielded the a-waves in B. Dashed horizontal lines and vertical intercepts on the abscissa show the method for determining threshold light intensities (I_t). Responses in B and C were recorded at ≤8, 10, 12, and 13 months from 12, 17, 7, and 4 Gcgr^−/− mice, respectively.