Phenotypic consequences after restoration of lymphopenia in the diabetes-prone BB/OK rat.

Besides other factors, lymphopenia (ll) is essential for development of insulin-dependent diabetes mellitus in the BB rat. It is unknown which phenotypic consequence may have a non-lymphopenia. Therefore, the region containing the lymphopenia gene of the BB/OK rat was replaced with that of the non-lymphopenic (LL) and hypertensive rat, SHR (11 cM, D4Mit6-LL-Npy-Spr). The resulting congenic strain, BB.LL, did not develop diabetes up to an age of 30 weeks and was non-T-lymphopenic. The SHR region did not influence the blood pressure of the BB.LL rat, but influenced obviously the motor activity, body weight, serum lipids, and the 24h urine excretion of urea, sodium, and potassium.