The effect of mercuric chloride on the excretion of two urinary enzymes in the rat

Abstract

The effect of intravenous injections of HgCl2 on the renal excretion of alkaline phosphatase (AP) and leucine aminopeptidase (LAP) was investigated in rats. On the first day after Hg enzyme excretion showed a linear rise with the Hg dose from a threshold value of 0.44 mg Hg/kg. On the second day a statistically significant effect was seen already after 0.25 mg HgKG. After doses of 0.75 mg/kg or more a decrease of enzyme activity below control values occurred which persisted for more than 4 days. Treatment with 2,3-dimercaptopropansulfonate (DMPS) brought about a normalization of AP excretion. An effect on LAP excretion was observed only with early treatment. The same holds for the effect of DMPS on Hg-induced lethality. The usefulness of a measurement of LAP excretion for estimating the exposure to inorganic mercury is discussed.

The Effect of Immediate and Delayed Treatment with 2,3‐Dimercaptopropane‐l‐sulphonate on the Distribution and Toxicity of Inorganic Mercury in Mice and in Foetal and Adult Rats

“…BAL-sulph given to rats 24 hrs after the HgC12injection is without effect on the survival of the animals according to Planas-Bohne (1977). Our observations of the renal pathology at autopsy 72 hrs after the HgCl2-injection seems in consistence with these results, since changes developed t o the same extent in the treated animals as in the controls.…”

“…Immediate or early chelation therapy is considered to be more effective than delayed treatment in metal intoxications (Catsch & Harmuth-Hoene 1975). By shortening the time interval between the HgCl2 exposure and BAL-sulph treatment from 24 to 6 hrs, Planas-Bohne (1977) could increase the survival of male rats. As seen in the present study, this knowledge of survival does not correlate with the amount of mercury in the kidneys (i.e.…”

Chelation for Heavy Metals (Arsenic, Lead, and Mercury): Protective or Perilous?

“…noted that all the animals survived when a single dose of the antidote was administered 5 min after the arsenical, as compared with no survival despite intensive repeated chelation initiated after a delay of 6 h. This finding that “chelation delayed is chelation diminished” has been demonstrated for other chelators studied in the context of acute intoxication by inorganic arsenic or mercuric salts. 7 , 8 , 9 Although chelation initiated late in the clinical course may still enhance urinary excretion of the metal, there can be no assurance that such delayed decorporation will influence the key measure of therapeutic efficacy, namely decreased morbidity and mortality.…”