EFFECT ON THE CANINE ECK FISTULA LIVER OF INTRAPORTAL TGF-BETA ALONE OR WITH HEPATIC GROWTH-FACTORS

Transforming growth factor-beta canceled the hepatocyte proliferation caused by transforming growth factor-alpha when the two substances were mixed and administered through a disconnected central portal vein branch after creation of an Eck fistula. In contrast, transforming growth factor-beta had no antidotal action on the stimulatory effects of insulin or full test doses of insulinlike factor-2, hepatocyte growth factor, epidermal growth factor or triiodothymanine. A minor antidotal effect on hepatic stimulatory substance activity could be detected, but only with hepatic stimulatory substance was given in doses smaller than those known to cause maximum stimulatory response. These results suggest a highly specific pharmacological and physiological interaction between transforming growth factor-alpha and transforming growth factor-beta in the modulation of liver growth control.