Glucose tolerance and insulin release in hypertensive patients treated with the cardioselective beta-receptor blocking agent metoprolol.

Blood glucose and plasma insulin levels were studied under fasting conditions and following an i.v. and an oral glucose load, respectively, in nine males with moderate hypertension before treatment, after one month on placebo and after three months on the cardioselective beta-receptor blocking agent metoprolol. The studies were performed under metabolic ward conditions. The reproducibility of blood glucose and plasma insulin values following an i.v. glucose load was very good. Medication with metoprolol caused no changes in the fasting levels of blood glucose or plasma insulin, nor in the blood glucose response following a glucose load given i.v. or orally. The initial and total integrated insulin response to the i.v. administration of glucose was similar before and during metroprolol. Following oral glucose both the total integrated blood glucose response and the insulin response were unaffected by treatment with metoprolol.