Dietary calcium and iron: effects on blood pressure and hematocrit in young spontaneously hypertensive rats.
Supplemental dietary calcium in spontaneously hypertensive rats (SHRs) aged 21-28 d produces a decrease in blood pressure and hematocrit. The simultaneous fall in hematocrit and blood pressure suggests that the changes in blood pressure may be, in part, a consequence of the decrease in hematocrit and reduction in viscosity. To examine this possibility, SHRs aged 21 d were placed on one of four diets varying in iron content. At age 28, the animals showed iron-induced variations in hematocrit (P less than 0.001) but no difference in blood pressure. Subsequent manipulation of the ratio of calcium and iron in the diets of additional groups of animals resulted in variations in hematocrit that were independent of the calcium-induced alterations in blood pressure. We conclude that the effects of calcium on blood pressure are relatively independent of its effects on hematocrit.
Hatton
D
D
Department of Medical Psychology, Oregon Health Sciences University, Portland 97201.
Muntzel
M
M
Absalon
J
J
Lashley
D
D
McCarron
D A
DA
D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002136:Calcium, Dietary / Q000494:pharmacology*; D004032:Diet; D004573:Electrolytes / Q000097:blood; D006400:Hematocrit; D007501:Iron / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR
D002136:Calcium, Dietary; D004573:Electrolytes; D007501:Iron