AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 1 146-R153, Copyright © 1984 by American Physiological Society
Liver and adipose tissue contributions to newly formed fatty acids in an ascites tumor
M. Ookhtens, R. Kannan, I. Lyon and N. Baker
We determined the contribution from host hepatic and extrahepatic tissues
to newly synthesized fatty acids (FA) in the Ehrlich ascites tumor (EAT).
We administered 3H2O (subcutaneously) and [14C]glucose (in a test meal) and
measured the appearance of radioactivity in plasma triglyceride fatty acids
(TGFA) and free fatty acids (FFA) and in tumor total lipid fatty acids
(TLFA). Using [14 C]FFA, we selectively labeled epididymal fat TGFA to
estimate the FA transport rate from intraperitoneal adipose tissue directly
to the tumor. Contributions of four major pathways to newly synthesized FA
in EAT were determined by multicompartmental analysis. De novo FA synthesis
by EAT accounted for more than 93% of the TLFA radioactivity found in the
tumor. Contributions from liver TGFA via plasma TGFA (less than 0.5%),
adipose tissue TGFA via plasma FFA (less than 6%), and adipose tissue TGFA
via direct intraperitoneal transport of FFA (less than 1%) accounted for
less than 7% of all TLFA radioactivity measured in the EAT. Thus the
present study establishes that practically all labeled esterified FA in the
EAT is derived from de novo synthesis by tumor cells.
