Spontaneous Diabetes Mellitus in a Female Cynomolgus Monkey (Macaca fascicularis)

A nine-year old female cynomolgus monkey (Macaca fasticularis) of feral origin was diagnosed with spontaneous diabetes based on abnormal glucose tolerance curve(K value, 0.968) and diminished plasma insulin levels during intravenous glucose tolerance test (IVGTT). Fasting glucose level was normal (106 mg/dL). Clinical signs characteristic of diabetes mellitus were not apparent at the time of diagnosis. Nine months after initial diagnosis, blood chemistry showed elevated fasting blood glucose (276 mg/dl.), GOT (731U/ L) and CPK (1602 1 U/L) levels. Urinalysis revealed slight glycosuria, slight proteinuria, alkaline pH and presence of urobilinogen. Body weight showed a decline from 3.6 (10/4/01) to  3.1 kg (7/4/02). Food consumption was also reduced prior to conduct of blood examination. Insulin therapy (0.4 U/kg body weight BID) was instituted to minimize further reductions in body weight as well as to control blood glucose level. Improvement in body weight, blood glucose level and food consumption were noted with insulin administration. However, the animal died six months later. Blood chemistry and urinalysis conducted two weeks prior to death showed hyperglycemia (259 mg/dL), hypertriglyceridemia (139mg/dL) and ketonuria. Histopathologic examination of the pancreas revealed the presence of large and small-sized islets. Large-sized islets were cellular with granular cytoplasm while small-sized islets were characterized by loss of secretory cells. Pancreas stained with Congo red revealed the presence of amyloid material confirming type 2 diabetes mellitus. There was slight swelling of the hepatocytes. In addition, the glomerul were  enlarged with almost complete obliteration of the Bowman's space. Thickening of glomerular basement membrane and disintegration of the tubular cells were present. Death could have been caused by diabetic ketoacidosis with renal dysfunction.