Résumé
Nucleoside triphosphates (NTPs) at 4-10 microM concentrations were found to inhibit the rates of collagen-induced in vitro mineralization and ion exchange reactions. The sequential removal of the terminal phosphate groups caused a step-wise decrease in their inhibitory potency. The results suggest that NTPs inhibit the rates of ion uptake and exchange reactions at concentrations much lower than their intracellular physiological concentrations. Thus NTPs may be involved in the control of biological mineralization and the tissues which mineralize under physiological conditions develop a system to locally convert NTPs to NDPs and NMPs.
Sujets)
Collagène/pharmacologie , Transport des ions/effets des médicaments et des substances chimiques , Cinétique , Minéraux/métabolisme , Nucléotides/pharmacologieRésumé
Rat urine could inhibit not only the in vitro initial precipitation of calcium and phosphate/oxalate ions as mineral phase but also the subsequent growth of the preformed mineral phase. Oral administration of the aqueous extract of a commercially available Ayurvedic compound preparation to rats, was found to significantly increase the ability of the urine samples to inhibit both the initial mineral phase formation and its subsequent growth.