AJP - Renal Physiology, Vol 259, Issue 1 104-F110, Copyright © 1990 by American Physiological Society
Developmental changes of Ca2+, PO4, and calcitriol metabolism in spontaneously hypertensive rats
P. Bourgouin, P. Lucas, C. Roullet, A. Pointillart, M. Thomasset, M. Brami, L. Comte, B. Lacour, M. Garabedian, D. A. McCarron and al. et
Institut National de la Sante et de la Recherche Medicale Unite 90, Hopital Necker-Enfants Malades, Paris, France.
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)
