Adenyl cyclase activity in Morris hepatomas 7777, 7794A, and 9618A.

Abstract

Summary Adenyl cyclase activity has been measured in Morris hepatomas, moderately fast-growing 7777 (average generation, 2 months) and slower-growing tumors 7794A (average generation, 4 months) and 9618A (average generation, 5 months). The activity levels of the tumors varied as a function of their growth rate. Slower-growing tumors exhibited adenyl cyclase activity which was higher than the normal level. The fastest-growing tumor (7777) had a much higher level of adenyl cyclase activity than did normal liver. All of the hepatomas had cyclase activity which was irregular in response to epinephrine facilitation of cyclization, thought to be a primary element of organismal control of cellular activity. Adenyl cyclase activity of the liver of hepatomatous animals differed from liver of healthy animals. The relationships were essentially the same as those of the several hepatomas themselves to the normal liver. The fastest-growing tumor had a higher adenyl cyclase activity; the slower-growing tumor approached that of the normal. Like the hepatomas themselves, the liver adenyl cyclase activity of hepatomatous animals was affected less by epinephrine than was normal liver.