Spontaneous diabetes mellitus in Macaca cyclopis and Mandrillus leucophaeus: case reports.

Spontaneous diabetes mellitus was reported in a Mandrillus leucophaeus (drill baboon) and a Mpacaca cyclopis (Formosan rock macaque). Each had hyperglycemia, impaired clearance of glucose during tolerance test, and reduced concentrations of immunoreactive insulin; the M cyclopis also had increased triglyceride and prebetalipoprotein concentrations. Both monkeys had extensive amyloid infiltration into the islets of Langerhans and loss of beta cells. Beta cell obliteration can account for the appearance of the diabetic syndrome in these and other nonhuman primate species.