c-peptide and Gigantism

A 17-year-old boy with pituitary gigantism who had two episodes of diabetic ketoacidosis is reported. Glucose tolerance and insulin secretion were evaluated before, during and after each episode of ketoacidosis. The patient was 201 cm tall and weighed 137 kg. Before surgery, his plasma growth hormone level was 3,000 ng/ml, glucose tolerance was almost normal and insulin response to glucose load was enhanced. He fell into diabetic ketoacidosis twice; 3 weeks after hypophysectomy and one year later after getting the "flu". On each occasion, insulin treatment was needed only temporarily. After the ketoacidosis improved, glucose tolerance and C-peptide responses became nearly normal. Urine C-peptide was low during and immediately after the second episode, but increased to normal following recovery. It is presumed that a pre-operative compensation for the diabetogenic action of excess growth hormone by hyper-secretion of insulin was broken when superimposed stress was added. This is an example in which subnormal insulin response may not be a prerequisite for the occurrence of a severe diabetic state, and decompensated insulin secretion leading to ketoacidosis may not imply permanent damage to the beta cells.

Topics: Adolescent; C-Peptide; Diabetic Ketoacidosis; Gigantism; Glucose Tolerance Test; Growth Hormone; Humans; Hypophysectomy; Insulin; Male; Pituitary Hormones, Anterior; Thyrotropin-Releasing Hormone