Experimental studies on globefish poison (I) Seasonal variation of the concentration, distribution in the fish body, and stablity of the poison

Globefishes offered to the experiments were limited to which were landed at the Shimonoseki fish market during a definite period from October to March. The results of experiments were shown as follows. (1) Seasonal variation of the concentration of the poison. Three species of globefish-Sphoeroides rubripes, S. porphyreus and S. albpplumbeus were used for this experiment. The concentration of the poison was near to zero in October and November, then it gradually increased in December and reached to the highest value in Janury to March. (2) Distribution of the poison in various tissues. Liver, ovary, testis, skin, intestine, heart, muscle and blood were used for the examination. The poison conttent of ovary was twice, especially in winter, that of liver. The other organs had apprently less content. Testis, in contrast with ovary, had no detectable poison. (3) Distribution of the poison in ovary. As ovary was most poisonous, it was devided into three parts-parenchyma, egg cells and tissue fluid-, and tested their toxicities respectively. The fluid part contained the highest concentration and the largest amount of the poison. The ratio of toxicities of the parenchyma, egg cells tissue fluid parts were shown ca. 1: 2 : 80 (concentration) and 1 : 2 : 70(amount). (4) Stability of the poison. A) For chemical ray: It was no effect on toxicity that exposure toquartz mercury lamp in less than 48 hours and to sunshine in less than one year in ampule. B) For heating: Heat resistances of the poison were as follows. Toxicity was unchanged at 60℃ for two days and decreased to the half at 80℃ for 10 hours and to 1/4 within 48 hours. In the case of 100℃ heating, the poison was almost destroyed after 5 hours. C) For acid and alkali : As indicated in Table 8, the poison was stable in weak acid solution and began to destroy over 0.5 N HCI and 2N CH_3COOH. Nevertheless, this poison was labile in weak alkaline solution. The change of hydrogen ion concentration of the solution in which the poison was diluted was effective to the toxicity. At the acid pH, the poison was comparatively stable, but at the alkaline pH, it was gradually reduced. D) For digestive enzymes : Peosin, trypsin, erepsin and amylopsin gave no effect on the toxicity when they were incubated at 38℃ for 48 hours.