Augmentation of the renal tubular dopaminergic activity by oral calcium supplementation in patients with essential hypertension.
We studied the effect of oral calcium supplementation on renal tubular dopaminergic activity in patients with mild to moderate essential hypertension. Fifteen patients aged 45 to 68 years (nine men and six women, mean age 59 +/- 7 [SD]) participated in the study. We orally administered calcium (1.0 g per day for 1 week) during hospitalization. The change in 24-h blood pressure (BP), measured by ambulatory BP monitoring, and excretions of electrolytes and catecholamines were investigated before and after 1 week of oral calcium supplementation. The mean values of 24-h systolic and diastolic BP showed no significant changes by calcium loading. Daily urinary excretion of free dopamine, sodium clearance (CNa), fractional excretion of sodium (FENa), and urinary volume were significantly increased by oral calcium supplementation. Urinary excretions of epinephrine and norepinephrine and creatinine clearance showed no significant changes by oral calcium treatment. CNa and FENa showed significant correlations with urinary excretion of free dopamine. These results suggest that oral calcium supplementation induces natriuresis partly through augmentation of renal tubular dopaminergic activity.
Dazai
Y
Y
Second Department of Internal Medicine, Ehime University School of Medicine, Japan.
Iwata
T
T
Hiwada
K
K
D000284:Administration, Oral; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology; D003404:Creatinine / Q000652:urine; D004298:Dopamine / Q000502:physiology* / Q000652:urine; D004837:Epinephrine / Q000652:urine; D005260:Female; D005527:Food, Fortified; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007684:Kidney Tubules / Q000737:chemistry* / Q000502:physiology; D008274:Magnesium / Q000097:blood; D008297:Male; D008875:Middle Aged; D009318:Natriuresis / Q000502:physiology; D009638:Norepinephrine / Q000652:urine; D010281:Parathyroid Hormone / Q000097:blood; D011188:Potassium / Q000097:blood; D012964:Sodium / Q000097:blood / Q000652:urine
D010281:Parathyroid Hormone; D012964:Sodium; D003404:Creatinine; D008274:Magnesium; D011188:Potassium; D002118:Calcium; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine