The role of cortisol in the peripheral granulocyte response to insulin-induced hypoglycaemia in man.

Abstract

Peripheral blood leukocyte counts and plasma hormonal changes in response to acute insulin-induced hypoglycaemia were examined in 16 patients undergoing assessment of pituitary function. Eight subjects had a normal cortisol secretory response (Group 1), and 8 patients had definite hypopituitarism in whom the cortisol responses were deficient or absent (Group 2). An equivalent degree of hypoglycaemia was achieved in both groups. In Group 1a biphasic rise in leukocyte count occurred following hypoglycaemia, with an early rise in lymphocytes at 15 minutes after the acute hypoglycaemic reaction, and a later rise in granulocytes. A similar rise in lymphocytes was observed in Group 2, but the rise in the granulocyte count was attenuated, increasing from a basal value of 3.6 +/- 0.6 x 10(9) cells/L to a peak of 7.4 +/- 1.1 x 10(9) cells/L, compared with a peak of 11.7 +/- 1.2 x 10(9) cells/L in Group 1 (P less than 0.05). The usual increment in plasma cortisol in response to hypoglycaemia occurred in Group 1, but plasma cortisol did not rise in Group 2. A correlation was observed between the magnitude of the granulocyte rise and the increment in plasma cortisol in individual subjects (r = 0.64, P less than 0.02). This suggests that the rise in peripheral granulocytes following insulin-induced hypoglycaemia in man is mediated by cortisol released from the adrenal gland, following activation of the hypothalamic-pituitary-adrenal axis.