Elevation of blood pressure in young rats fed a low calcium diet. Effects of nifedipine and captopril.
Hypertension was developed in 5-week-old male rats fed a low calcium diet, which evokes hypocalcemia and nutritional hyperparathyroidism, for 2 weeks. Blood pressure returned to normal after changing to a normal calcium diet. These changes of blood pressure were preceded by changes of calcium levels in plasma. In parathyroidectomized rats receiving a normal calcium diet, blood pressure did not rise, though the plasma calcium level decreased to a similar extent as in rats fed the low calcium diet. These findings seem to indicate that hyperparathyroidism, not hypocalcemia, is involved in the elevation of blood pressure in rats fed a low calcium diet. The elevated blood pressure was reduced by a calcium antagonist, nifedipine, but not by an inhibitor of angiotensin-converting enzyme, captopril. This may indicate that hypertension due to nutritional hyperparathyroidism responds to the calcium antagonist nifedipine and calcium supplementation, and is not dependent on renin.
Togari
A
A
Department of Pharmacology, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.
Arai
M
M
Shamoto
T
T
Matsumoto
S
S
Nagatsu
T
T
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D002118:Calcium / Q000008:administration & dosage* / Q000097:blood / Q000172:deficiency; D002216:Captopril / Q000494:pharmacology*; D004032:Diet; D004195:Disease Models, Animal; D006339:Heart Rate / Q000187:drug effects; D006961:Hyperparathyroidism / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D002216:Captopril; D009543:Nifedipine; D002118:Calcium