N. Angayarkanni et R. Selvam, ENHANCED RENAL VITAMIN-K-DEPENDENT GAMMA-GLUTAMYL CARBOXYLASE ACTIVITY IN EXPERIMENTAL RAT UROLITHIASIS, European urology, 33(1), 1998, pp. 116-120
Objective: To detect the role of the enzyme gamma-glutamyl carboxylase
in an experimental stone-forming condition. Methods: Urolithiasis was
induced in experimental rats by (i) oral feeding of 1% ethylene glyco
l (EG) and (ii) feeding a calculus-producing diet containing 3% sodium
glycolate. Results: A significant enhancement in the activity of rena
l vitamin-K-dependent gamma-glutamyl carboxylase was observed in both
groups of experimental urolithic rats. Dicoumarol as well as EG treatm
ent enhanced the accumulation of the endogenous substrate for the enzy
me. The carboxylase activity was stimulated by sodium oxalate as well
as calcium oxalate in vitro. A positive correlation was observed betwe
en lipid peroxidation and the renal gamma-glutamyl carboxylase activit
y. Conclusion: The enhanced carboxylase activity observed in the hyper
oxaluric condition is suggested to be due to stimulation of the enzyme
by oxalate/ calcium oxalate, increased concentration of endogenous ca
rboxylase substrate and lipid peroxidation.