Abstract

The effect of ethionine and CCl₄ on the urethan or phenobarbital shortening of hexobarbital sleeping time was studied in mice. If ethionine or CCl₄ was given simultaneously with urethan or phenobarbital, the normally observed shortening response was blocked. If, however, ethionine or CCl₄ was given 24 hours after the urethan or phenobarbital, the response was not blocked. These data are interpreted to indicate that the urethan and phenobarbital responses may be due to enzyme induction. These effects were produced with doses of ethionine and CCl₄ which had no effect on normal sleeping time and bromsulfalein retention.