Congenic diabetes-prone BB.Sa and BB.Xs rats differ from their progenitor strain BE/OK in frequency and severity of insulin-dependent diabetes mellitus

Two newly established congenic diabetes-prone BE rat strains designated BB. Sa and BB.Xs carrying a region of chromosome 1 (Sa-Lsn-Secr-Igf2-Tnt, 16 cM ) and a region of chromosome X (DXMgh3-Mycs/Pfkb1-Ar, 36 cM) of the SHR rat s, respectively, were studied to determine whether the transferred chromoso mal regions influence diabetes frequency, age: at onset, and clinical pictu re. Therefore, 4 complete litters of BB/OK (n = 43), BB.Sa (n = 45), and BB .Xs (n = 41) were observed for diabetes occurrence up to the age of 30 week s. From these litters 6 diabetic males of each strain manifesting in an int erval of 1 week were chosen to study body weight, blood glucose, insulin re quirement to survive, and several diabetes-related serum constituents at on set of diabetes and after a diabetes duration of 150 days. The diabetes fre quency was significantly lower in BB.Xs than in rats of the parental strain BB/OK, whereas comparable frequencies were found between BB/OK and BB.Sa r ats. Obvious differences were observed 150 days :after diabetes onset betwe en BB/OK and both BB.Sa and BB.Xs rats. BB/OH rats were significantly heavi er and needed significantly more insulin/100 g body weight than BB.Sa and B B.Xs rats. Comparisons of the serum constituents as lipids, proteins, and m inerals revealed significant differences between diabetic BB/OK rats and th eir diabetic congenic derivatives in several traits studied at onset and af ter 150 days of insulin treatment. These results not only show the lower of congenic lines in diabetes research, but indicate for the first time that there are genetic factors on chromosomes 1 and X influencing frequency and severity of diabetes in the BB/OK rat. (C) 1999 Academic Press.