Unchanged insulin secretion and glucose tolerance but increased insulin clearance during long-term calcium antagonism with felodipine in essential hypertension.

Studies were performed to explore the effect of calcium antagonism with felodipine for 8 weeks on glucose homeostasis and serum lipids in 8 patients with essential hypertension. Fasting levels of blood glucose as well as serum C-peptide, insulin, glucagon and free fatty acids were unchanged following felodipine. During an intravenous glucose tolerance test, the incremental area under the curve for C-peptide and glucose was unchanged, but decreased for insulin, after felodipine. The decremental area over the curve for glucagon and free fatty acids remained unchanged. Fasting serum total cholesterol and high density lipoprotein cholesterol were unaltered, whereas triglycerides decreased following felodipine. The findings indicate that calcium antagonism with felodipine does not affect glucose-induced insulin release in vivo. The increased insulin clearance could be expected to be coupled to a change in glucose tolerance, but this was unaltered during long-term calcium antagonism.