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Hyperfiltration and calcium metabolism in essential hypertension
C Zoccali1, F Mallamaci, M Postorino
1Divisione di Nefrologia, CNR Centro Fisiologia Clinica, Reggio Cal, Italy.
American Journal of Hypertension
|December 1, 1991
Summary
Essential hypertension is linked to altered calcium metabolism, affecting kidney function. Lowering calcium intake significantly impacts glomerular filtration rate (GFR) in hypertensive individuals, particularly those with hypercalciuria.
Area of Science:
- Nephrology
- Endocrinology
- Cardiovascular Medicine
Background:
- Essential hypertension is often associated with hyperfiltration, a condition where the glomerular filtration rate (GFR) is elevated.
- The role of calcium metabolism in regulating GFR in hypertension remains incompletely understood.
Purpose of the Study:
- To investigate the relationship between urinary calcium excretion and GFR in untreated essential hypertensives.
- To determine the influence of varying calcium intake on GFR in essential hypertension and normotensive controls.
Main Methods:
- Studied 38 untreated essential hypertensives on a free diet, assessing urinary calcium and GFR (creatinine clearance).
- Examined GFR changes in 30 essential hypertensives (15 hypercalciuric, 15 normocalciuric) and 11 controls with fixed low and high calcium diets.
Main Results:
- A direct correlation was observed between urinary calcium excretion and GFR in free-diet hypertensives.
- GFR was significantly higher on low calcium intake compared to high calcium intake in essential hypertensives.
- This low-calcium-induced hyperfiltration effect was prominent in hypercalciuric patients and hypertensive women.
Conclusions:
- Alterations in calcium metabolism significantly influence GFR regulation mechanisms in essential hypertension.
- Calcium intake modification impacts GFR, suggesting a role for calcium in hypertensive nephropathy.
- Hypercalciuria and sex may modulate the relationship between calcium metabolism and GFR in hypertension.