Post-hypophysectomy insulin response in patients with advanced breast cancer

Seven postmenopausal women with metastic breast cancer underwent transsphenoidal hypophysectomy. The rate of disappearance, k*, of iv glucose and insulin following iv glucose and l-arginine infusion was determined before and after the ablation. The k* was estimated with a linear least squares weighted regression method. The insulin secretory capacity of the pancreas before and after the ablation was evaluated with the index of insulinogenic reserve, the index representing the quantity of insulin secreted per unit of glycemic stimulus. Following iv glucose and arginine, there was no significant difference in the mean k* for glucose and insulin, before and after the ablation. The insulinogenic index before was lower than the normal. After hypophysectomy, the index decreased further for the first 30 min following iv glucose. In patients with advanced cancer the index of insulinogenic reserve is lower than normal and is suppressed further by hypophysectomy.