[Experimental studies on anthelmintics (XXVI). Biochemical and pharmacological studies of 4-iodothymol on Ascaris lumbricoides suum].

We have shown previously that 4-iodothymol (IT) produces a contraction in Ascaris muscle, probably due to the myogenic action. In this paper, the effects of IT on the carbohydrate metabolism in Ascaris muscle have been investigated in comparison with those of hexylresorcinol (Hex), santonin (S) and piperazine (Pip). (1) Hex (200 approximately 400 mug/ml) showed a strong nonspecific inhibition on the formation of succinate from fumarate in muscle homogenate, the phosphofructokinase (PFK) activity in cytoplasm, and the electron transfer activity in mitochondria. (2) S(100 approximately 400 mug/ml) and Pip (100 approximately 400 mug/ml) were inneffective on these activities. (3) IT inhibited the formation of succinate from glucose and fumarate in muscle homogenate (100 approximately 400 mug/ml), the PFK activity in cytoplasm (400 mug/ml), and the mitochondrial succinate oxidase system (25 approximately 400 mug/ml). These results suggest that IT elicits the wormcidal action by inhibiting the energy metabolism of Ascaris muscle mitochondria.