@article{oai:ir.kagoshima-u.ac.jp:00005202,
 author = {小林, 昭 and 寺師, 慎一},
 journal = {南方海域調査研究報告=Occasional Papers},
 month = {2016-10-28},
 note = {Although the seeds of cycad plants have been used as a food in southern areas in
Japan, people have known that it was toxic without adequate removal of the toxin.
The toxin in Japanese Cycas revoluta Thunb. was isolated and the structure of the
toxin was elucidated as Cycasin, methylazoxymethyl - β - D-glucoside, by Nishida, Kobayashi and Nagahama in 1955.
Laqueur et al. (1963) found that the cycad seeds in Guam had carcinogenic actions in experimental animals through his studies about persumed relationship between
ingestion of cycad seeds and neurogenic disorders in men and cattle.
The results of many studies indicated that the toxicity and the carcinogenicity
of Cycasin were revealed after the enzymatic hydrolysis of Cycasin to the aglycon
(Methylazoxymethanol) and that this conversion was brought about in vivo by the
action of β -glucosidase, most likely of intestinal bacterial origin.
Studies about carcinogenic action of Cycasin and morphological studies on hepatic
cancer were carried out in two age-groups of Sprague-Dawley strain rats induced
given 10mg/kg body weight of Cycasin in drinking water through experimental periods.
Fourteen cases each of hepatic cancer were observed in both sexes (17 females and
16 males) in 21-day-old group of animals between 167 and 487 experimental days in
female rats, and between 203 and 438 in male rats. In 50-day-old (20 rats each in
both sexes), 18 each of hepatic cancer were observed between 251 and 556 in female
rats, and between 280 and 556 in male rats.
Macroscopic findings of hepatic tumors were graysh-white nodules with focal hemorrhagic lesions. Macroscopically, most of hapatoma were composed of well differentiated type of hepatocellular carcinoma with trabecular pattern of the tumor cells.
And clear cell type of adenocarcinoma, intestinal metalasia type of cancer and pleomorphic cell carcinoma were also observed, but these types of cancer were rare cases.
Some cases had sarcomatous pattern of tumor growth. Only one case had liver cirrhotic changes with well differentiated type of hepatoma.
Electronmicroscopic findings of tumor cell, such as peroxsomes, tight junctions
and bile ductlesses between the tumor cells, suggested that most of the tumor were
hepatic cell origin., 小林昭（鹿児島大学農学部農芸化学科）, 寺師慎一（鹿児島大学南方海域研究センター）},
 pages = {1--23},
 title = {ソテツ種子含有配糖体(Cycasin)による実験的肝癌},
 volume = {6},
 year = {}
}