Effect of insulin-induced hypoglycemia on adrenergic responsiveness and forearm haemodynamics in low- and normal-high-renin hypertension

In order to elucidate possible differences in adrenergic responsiveness and forearm haemodynamics between patients of different renin-status, hypoglycemia was induced by insulin in seven patients with low-renin and in seven patients with normal-high-renin hypertension. Nearly identical nadir plasma glucose values were obtained 45 min after insulin administration. Simultaneously, plasma adrenaline and plasma noradrenaline concentrations as well as plasma renin activity increased in both groups of patients indicating an increased sympathetic nervous activity whereby renin release was stimulated. However, plasma renin activity remained significantly lower in the low-renin group compared with the normal-high-renin group during hypoglycemia. No significant differences were found between the two groups in basal values or in changes of plasma catecholamines. Mean blood pressure and calculated forearm vascular resistance decreased, whereas forearm blood-flow increased, which indicates that the β2 receptor vasodil...