Effect of FK 506 on spontaneous diabetes in BB rats.

From days 30-120 after birth, 59 BB rats were treated with water (n = 20) or FK 506 in intragastric doses of 1 mg.kg-1.day-1 (n = 19) or 2 mg.kg-1.day-1 (n = 20). Diabetes developed in 75, 15, and 0% of the 3 groups, respectively. Animals protected from diabetes by FK 506 had normal intraperitoneal glucose tolerance tests, virtual absence histopathologically of autoimmune insulitis, and normal pancreatic insulin content. Forty-five to 75 days after stopping FK 506, approximately 75% of the rats that were diabetes free at 120 days remained so.