Study on the cupric phenanthroline-induced beta-glucuronidase release in saponin-permeabilized polymorphonuclear leukocytes.
Saponin-permeabilized polymorphonuclear leukocytes (PMNs) released beta-glucuronidase, a lysosomal enzyme, dose-dependently in response to cupric phenanthroline (CuPh), a mild oxidant, which catalyzes the formation of disulfide bridges. The beta-glucuronidase release induced by CuPh was inhibited by ethylene glycol bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). Both dithiothreitol (DTT) and N-(6-aminohexyl)-5-chloro-naphthalene sulfonamide (W-7) also inhibited the beta-glucuronidase release induced by CuPh. CuPh elicited a decrease in protein-bound free sulfhydryls simultaneously, and this decrease was not restored by EGTA treatment. CuPh inhibited Ca2+ uptake into Ca2+ store sites, and promoted a Ca2+ efflux from Ca2+ store sites. It also inhibited Ca(2+)-adenosine triphosphatase (ATPase) activity in permeable PMNs. DTT, a sulfhydryl reducing agent, suppressed both the beta-glucuronidase release and the Ca2+ uptake in CuPh-treated permeable PMNs. On the other hand, chloromercuriphenylsulfonic acid (CMPS), a sulfhydryl modifier, decreased the amount of free sulfhydryls in protein and released beta-glucuronidase in permeable PMNs dose-dependently, but EGTA did not inhibit either reaction. Neither CuPh nor CMPS released beta-glucuronidase from intact PMNs. These results indicate that both CuPh and CMPS act on intra-PMN target molecules to exert their influence, but the involved mechanisms are different in nature. Alteration in calcium movement is responsible for the beta-glucuronidase release in the CuPh-treated permeable PMNs.
Adachi
I
I
Department of Hospital Pharmacy, Toyama Medical and Pharmaceutical University, Japan.
Murase
A
A
Ueno
M
M
Horikoshi
I
I
D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D005966:Glucuronidase / Q000097:blood*; D006168:Guinea Pigs; D008297:Male; D009504:Neutrophils / Q000201:enzymology* / Q000502:physiology; D010618:Phenanthrolines / Q000494:pharmacology*; D012503:Saponins / Q000494:pharmacology*
D010618:Phenanthrolines; D012503:Saponins; C014741:bis(1,10-phenanthroline)copper(2+) ion; D005966:Glucuronidase