Effects of intracellular sodium concentration on the bone resorption in organ culture.
- Author:
Tai Joon LEE
1
;
Won Sik YANG
Author Information
1. Department of Orthodontics, College of Dentistry, Seoul National University, Korea.
- Publication Type:Original Article
- MeSH:
Amiloride;
Animals;
Bone Resorption*;
Injections, Subcutaneous;
Membranes;
Monensin;
Organ Culture Techniques*;
Ouabain;
Pregnancy;
Rats;
Sodium*;
Ulna;
Veratridine
- From:Korean Journal of Orthodontics
1989;19(1):61-75
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
Recently, indirect evidences suggest that Na-Ca exchange mechanism is involved in bone resorption. To study this suggestion, effects of several drugs which increase the intracellular sodium concentration by different mechanisms on the PTH-induced bone resorption were analysed employing organ culture. Ulnae and radii were removed from 19-day fetal rats, prelabelled by subcutaneous injection of 200micron Ci 45CaCl2 on the 17th day of gestation, and then explanted on the membrane filters in organ culture dishes. For studying the effects of amiloride, ouabain, monensin, and veratridine on the PTH-induced bone resorption, control group was cultured in BGJb media containing PTH (0.4U/ml) while experimental group was cultured in BGJb media containing PTH and drugs. The effects of drugs on the PTH-induced bone resorption were observed by the ratios of %-release of 45Ca between paired control and experimental groups. The results were as follows: 1. 45Ca release was significantly increased by PTH (0.4U/ml) at 48 and 72 hours of culture. 2. Amiloride, at concentration of 500micronM, significantly inhibited the PTH-induced bone resorption after 48 and 72 hours of culture. 3. Ouabain, at concentration of 0.1mM, presented significant inhibition of PTH-induced bone resorption after 48 and 72 hours of culture, and at 0.5mM and 1mM, presented significant inhibition of PTH-induced bone resorption after 72 hours of culture. 4. Monensin, at concentration of 500nM, significantly inhibited PTH-induced bone resorption after 72 hours of culture. 5. Veratridine, at concentration of 0.5mM, presented significant inhibition of PTH-induced bone resorption after 48 and 72 hours of culture, and at 1mM, presented significant inhibition of PTH-induced bone resorption after 72 hours of culture. Taken altogether, these results suggest that Na-Ca exchange mechanism playa role in PTH-induced bone resorption.
