Diagnosis of diabetes mellitus in a bull by means of butyrate infusion.

A 9-month-old bull was presented with a history of runting and glucosuria. The bull showed major signs of diabetes mellitus, such as polyuria, polydipsia, polyphagia, emaciation, glucosuria, and ketonuria, but persistent hyperglycemia was missing. Because in an intravenous glucose tolerance test glucose disappearance was only insignificantly more rapid in a non-diabetic age-matched control than in the diabetic bull a butyrate-stimulated insulin response test was performed. Insulin response to butyrate infusion was markedly impaired in the diabetic bull compared with the non-diabetic bull. At necropsy hepatic cirrhosis was noticed and suggestive signs for diabetes mellitus were seen in liver and kidneys.