Effects of Thorium on Blood and Liver Enzymes of White Rats

Abstract

In a previous communication 1 some of the effects of thorium, zirconium, titanium and cerium on enzyme action in vitro were reported. Due to the peculiar physico-chemical properties of these metals, especially in respect to their precipitability in protein solutions it was deemed advisable to determine whether these effects could be observed in vivo. Roussy, Oberling and Guerin 2 have reported that thorium dioxide is carcinogenic when administered intraperitoneally to rats. In this investigation an attempt is being made to determine the effects produced by the intraperitoneal injection of varying amounts of soluble thorium nitrate, Th(NO₃)₄, on a variety of the blood and liver enzymes of the adult white rat.

The effects upon the following enzymes were investigated: blood amylase, blood lipase, blood esterase and blood phosphatase. The following liver enzymes were investigated : liver amylase, liver lipase, liver esterase, liver phosphatase, liver xanthine dehydrogenase, liver glucose dehydrogenase, and liver lactic dehydrogenase. Amylase was determined by the Willstatter-Schudel method, 3 lipase and esterase by the method suggested by Sure et al., 4 phosphatase by the method described by Bodansky 5 and the inorganic phosphorus determined by the method of Fiske and Subbarrow. 6 The dehydrogenase activities were estimated by the Thunberg technique as adapted by Collett. 7

Twenty-one adult white rats were used for the study. Two sets of controls were run. One set of controls was inoculated with physiological saline and the other received an injection of dilute hydrochloric acid equivalent to the acid strength of the thorium injected into the experimental animals.