Altered cation transport in non-insulin-dependent diabetic hypertension: effects of dietary calcium.
Erythrocyte cation transport and intracellular calcium in 15 black type II diabetic hypertensives were compared with 11 otherwise similar non-diabetic hypertensives and 16 normal black adults. The diabetic hypertensives were then randomized into either a placebo group or a calcium-supplemented (600 mg/day) group and studied again after 4 weeks. Na+,K+-ATPase activity was significantly lower in both groups of hypertensives than in the normotensives. In contrast, Ca-ATPase activity was similar among the non-diabetic hypertensive and normotensives but was markedly (approximately 60%) suppressed in the diabetics, while intracellular calcium was proportionally elevated. Calcium supplements significantly increased Ca-ATPase activity and reduced intracellular calcium and blood pressure compared with the placebo group. We conclude that type II diabetes is characterized by a defect in Ca-ATPase which may be responsible for increases in intracellular calcium and vascular resistance and which is partially corrected by dietary calcium supplementation.
Zemel
M B
MB
Division of Endocrinology, Metabolism and Hypertension, Wayne State University, Detroit, Michigan 48202.
Bedford
B A
BA
Zemel
P C
PC
Marwah
O
O
Sowers
J R
JR
D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000008:administration & dosage*; D000252:Calcium-Transporting ATPases / Q000097:blood; D002412:Cations / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000150:complications*; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood
D002136:Calcium, Dietary; D002412:Cations; D012964:Sodium; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium