ABSTRACT
Peroxisomes are single-membrane-bound organelles present in almost all eukaryotic cells. Hypolipidemic agents such as clofibrate, herbicides and plasticizers induce an increase in the number and size of peroxisomes from mammalian cells. However, there is no evidence of drugs causing a decrease in the number of these organelles. In this paper, we report the effect in vivo of toxin T-514 extracted from the plant Karwinskia humboldtiana, now re-named peroxisomicine-A1, on hepatic peroxisomes from rats intoxicated with this compound. Rats were treated with a single dose of 25 mg/kg of peroxisomicine-A1 and at different times were killed by decapitation. For the peroxisomal counting, liver tissue sections from control and treated rats were processed for the localization of catalase in peroxisomes. The results of the quantitative analysis demonstrated a significant decrease in the number of liver peroxisomes from rats intoxicated with peroxisomicine-A1. This finding suggests that peroxisomicine-A1 as in yeast, causes a damage to mammalian peroxisomes. The diminution in the number of peroxisomes could be a consequence of damage to the organelle, which is further removed by an autophagic process.
Subject(s)
Anthracenes/toxicity , Cytotoxins/toxicity , Liver/ultrastructure , Microbodies/ultrastructure , Animals , Catalase/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Female , Liver/drug effects , Liver/enzymology , Male , Microbodies/drug effects , Microbodies/metabolism , Rats , Rats, Wistar , Time FactorsABSTRACT
Peroxisomicine is a toxic compound isolated from plants of the genus Karwinskia (Rhamnaceae). This toxin produces irreversible and selective damage to the peroxisomes of yeast cells in vivo. Peroxisomicine also inhibits catalase activity in vitro, when using purified enzyme. This paper reports on the effect of peroxisomicine on liver catalase in tissue fragments, in situ, as well as in mice intoxicated with peroxisomicine, in vivo. The catalase activity was determined by biochemical and histochemical methods. In contrast with the reported findings in vitro, the results demonstrate that there is no inhibition of the activity of tissue catalase, and suggest that catalase in situ and in vivo is protected against the inhibitory effect of peroxisomicine by an unknown factor.