Effects of morphine on the level of the free fatty acids in the serum of rats.

It is well known that morphine produces hyperglycemia in some laboratory animals such as rats, dogs and so on (1) by inducing the release of catecholamine from the adrenal medulla (2). As catecholamine raises the level of free fatty acids (FFA) in blood as well as that of glucose (3), there would be a possibility that morphine also raises the level of FFA in blood. On the other hand the changes of FFA in serum by the administration of morphine were reported scarcely (4, 5). The purpose of the present investigation was to examine the changes of the level of FFA in serum of the morphine-tolerant and non tolerant rats by the administration of or by the withdrawal from morphine, and was also to see whether the level of FFA in serum of the rats changed in parallel with that of glucose in blood when the rats were treated with morphine. In some cases, the content of FFA of the epididymal fat pad and the rate of lipolysis were examined in order to know the effect of morphine on the lipolysis of the adipose tis sue, which is supposed to change the level of FFA in serum.