Insulin-like Growth Factors I and II, Prolactin, and Insulin in 19 Growth Hormone-Deficient Children with Excessive, Normal, or Decreased Longitudinal Growth after Operation for Craniopharyngioma

We studied insulin-like growth factors (IGF) I and II, prolactin, and the insulin response to arginine in 19 children with craniopharyngioma and documented growth hormone deficiency. Patients were divided into three groups according to their growth rate during the first postoperative year. Seven patients with excessive growth (Group A) had hyperinsulinism, normal IGF values, elevated basal prolactin levels, and a delayed thyrotropin response to thyrotropin-releasing hormone, which was compatible with hypothalamic lesions. In the six patients with normal growth (Group B), the insulin level was low; all other hormone values were similar to those of Group A. In the six patients with decreased growth (Group C), levels of IGF I, insulin, prolactin, and thyrotropin were low, indicating the presence of severe pituitary damage and explaining the failure to grow. Patients in all groups had low or undetectable basal levels of growth hormone. We conclude that in Group B, normal IGF permitted normal growth, and prolactin hypersecretion may have been responsible for normal IGF I values. Excessive growth in Group A may have been caused by hyperinsulinism associated with hyperphagia and obesity of hypothalamic origin.