Altered pressor response to norepinephrine in calcium- and vitamin D-deficient rats.
Norepinephrine (NE: 100-1000 ng/kg) pressor response studies in calcium- (0.005, 0.17, 1.4, and 2.8% in diet) and vitamin D-supplemented (0, 95, 190, and 950 U vitamin D3/day) normotensive conscious male rats were performed prior to and after administration of propranolol (100 ng/kg). Eight weeks of the above dietary treatments (beginning at 4 weeks of age) increased blood pressure (B.P.) in the 0.005% Ca group but reduced it in the 2.8% Ca group compared with the 1.4% Ca (control) group, whereas infusion of NE produced increased and decreased pressor responses, respectively. In the vitamin D groups, B.P. was increased only in the 0 U group, but NE pressor response was decreased in all groups compared with the 190 U (control) group. Plasma and bone calcemic parameters reflected disturbed Ca metabolism due to Ca and vitamin D deficiencies and excesses. These data suggest that Ca and vitamin D-induced changes in B.P. regulation in rats may in part be due to an altered adrenergic system.
Baksi
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Department of Veterinary and Comparative Anatomy, Washington State University, Pullman 99163-6520.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000097:blood / Q000172:deficiency* / Q000378:metabolism; D002136:Calcium, Dietary / Q000008:administration & dosage; D007262:Infusions, Intravenous; D008297:Male; D009638:Norepinephrine / Q000008:administration & dosage*; D051381:Rats; D011919:Rats, Inbred Strains; D014807:Vitamin D / Q000008:administration & dosage; D014808:Vitamin D Deficiency / Q000097:blood / Q000503:physiopathology*
D002136:Calcium, Dietary; D014807:Vitamin D; D002118:Calcium; D009638:Norepinephrine