INS and diabetes mellitus: (C) Islet lysates from LepRdb/+ heterozygote (control) or LepRdb/db mice at different stages of diabetes progression (random blood glucose values shown above; blood glucose in LepRdb/+male was 138 mg/dL and in female was 117 mg/dL) were analyzed by nonreducing or reducing SDS-PAGE and immunoblotting with mAb anti-proinsulin (CCI-17, above black line; molecular mass markers are noted) or guinea pig anti-insulin (below black line).