Hepatic insulin extraction after major hepatectomy.
BACKGROUND
After major hepatectomy, the remaining liver compensates for its reduced mass and maintains euglycemia through increased hepatic glucose output. The mechanism of this compensation may be a diminished hepatic extraction of portal insulin, which thereby decreases the suppressive effects of insulin on gluconeogenesis.


METHODS
Extraction of insulin by the liver was measured using the isolated perfused rat liver model. Fasted Sprague-Dawley rats were studied at 1, 2, 3, 4, 6, and 14 days after 70% hepatectomy. Control rats had no operation, and sham rats were studied 1 day after a sham laparotomy. The difference between portal and caval insulin concentrations was determined and reported as micromoles of insulin extracted per gram liver per minute.


RESULTS
Insulin extraction decreased from 191 +/- 22 microU/gm liver/min in control rats to 87 +/- 13.2 microU/gm liver/min at postoperative day 1 (p = 0.0001). Extraction normalized by postoperative day 6. Extraction rates in rats recovering from sham laparotomy were similar to control rats (p = 0.088), suggesting that decreased extraction in hepatectomized rats was not due to postoperative stress.


CONCLUSIONS
After 70% hepatectomy, the remaining liver extracts less insulin per gram. This may explain the ability of the reduced liver mass to maintain euglycemia after major hepatectomy.
Kogut
K A
KA
Department of Surgery, School of Medicine and Dentistry, University of Rochester, N.Y., USA.
Nifong
L W
LW
Witt
M J
MJ
Krusch
D A
DA
D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D006498:Hepatectomy; D066298:In Vitro Techniques; D007328:Insulin / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D008099:Liver / Q000098:blood supply / Q000502:physiology*; D008112:Liver Glycogen / Q000378:metabolism*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D009929:Organ Size; D010477:Perfusion; D011168:Portal System; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014682:Vena Cava, Inferior
D001786:Blood Glucose; D007328:Insulin; D008112:Liver Glycogen