Developmental changes of Ca2+, PO4, and calcitriol metabolism in spontaneously hypertensive rats.
We have measured Ca and P balance, serum calcitriol, and vitamin D-dependent intestinal calcium-binding protein (CaBP9k) in the spontaneously hypertensive rat (SHR) and its normotensive control, the Wistar-Kyoto rat (WKY) at 4-5 and again at 13-14 wk of age. In rats on a 1% Ca diet, P balance was significantly more positive in the 5-wk-old SHR than WKY (P less than 0.01); Ca balance tended to be greater in the 5-wk-old SHR. In contrast, in the 14-wk-old SHR, P and Ca balance were less positive than in the WKY (P was 5.8 +/- 1.3 vs. 13 +/- 1.7 mg/day, P less than 0.01, and Ca was 53 +/- 4.6 vs. 67 +/- 2.7 mg/day, P less than 0.05). On the 1% Ca diet, plasma calcitriol levels of the 5-wk-old SHR were higher than those of the WKY (58 +/- 3.2 vs. 40 +/- 2.1 pg/ml, P less than 0.002), whereas at 12 wk there was no difference. On Ca-deficient (0.1%) diets, plasma calcitriol was increased in 5-wk-old and 12-wk-old SHR and WKY, compared with the 1% Ca diet (P less than 0.001). Calcitriol metabolic clearance rate was the same in the 13-wk-old SHR and WKY on either Ca diet. Intestinal CaBP9k content of the 5-wk-old (38 +/- 2.6 vs. 40 +/- 3.9 micrograms/mg) and the 12-wk-old (11 +/- 1.6 vs. 14 +/- 1.4 micrograms/mg) SHR and WKY were similar on the 1% Ca diet.(ABSTRACT TRUNCATED AT 250 WORDS)
Bourgouin
P
P
Institut National de la Santé et de la Recherche Médicale Unité 90, Hôpital Necker-Enfants Malades, Paris, France.
Lucas
P
P
Roullet
C
C
Pointillart
A
A
Thomasset
M
M
Brami
M
M
Comte
L
L
Lacour
B
B
Garabédian
M
M
McCarron
D A
DA
D000375:Aging / Q000378:metabolism; D000818:Animals; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood / Q000378:metabolism*; D002118:Calcium / Q000008:administration & dosage / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000032:analysis; D004032:Diet; D006973:Hypertension / Q000378:metabolism*; D007422:Intestines / Q000032:analysis; D008297:Male; D010710:Phosphates / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D002135:Calcium-Binding Proteins; D010710:Phosphates; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium