TOXICITY OF OLAQUINDOX IN RATS

The oral toxicity of Olaquindox, antibacterial substance and growth pr omoter, was evaluated in rats exposed in utero and during lactation. T reatment was continued for three months after weaning. Administered do ses were 0,5, 5 and 50 mg/kg body weight. Olaquindox had no effect o n the reproductive performance and the development of newborn rats. In subchronic treatment with 50 mg/kg, Olaquindox decreased the growth ra te of rats (- 10 p.cent) in both sexes. Adrenal relative weight was sl ightly increased without change of the microscopic structure of the gl and. Olaquindox has no hepatotoxic effect but treatment with the highe st dose increased the relative liver weight and induced (25 to 50 p.ce nt) the activities of some microsomal enzymes, especially the UDP-gluc uronyltransferase activity in male rats. Olaquindox induced an hypertr ophy of the thyroid follicular cells in male rats. This effect could b e related to an increase of the metabolism and the excretion of thyrox ine as glucurono-conjugates in bile. Plasma concentrations of Olaquind ox seemed to indicate a low and time-limited impregnation of the rat o rganism after a three month administration.