Selective hypoglycemia in the liver induces adrenomedullary
counterregulatory response.
Lamarche, Louis, Nobuharu Yamaguchi, and Francois P[acute]eronnet.
Groupe de Recherche sur le Syst[grave]eme Nerveux Autonome,
Facult[acute]e de Pharmacie and D[acute]epartement d'Education
Physique, Universit[acute]e de Montr[acute]eal, Montr[acute]eal,
Qu[acute]e., Canada H3C 3J7
APStracts 3:0003R, 1996.
The present study was designed to investigate adrenal medullary
responses to a regional hypoglycemia selective in the liver of dogs
with hepatic cross-perfusion. The liver of recipient dogs (Rc) was
perfused with vena caval and aortic blood of donor dogs (Dn) through
the portal vein and hepatic artery, respectively. Total hepatic
venous blood of Rc was returned to Dn through the left jugular vein.
Upon the cross-perfusion, glucose (Glc, 5%) was infused at an average
rate of 3.5 +/- 0.2 mg x kg-1 x min-1 (n=12) in Rc to compensate the
loss of hepatic Glc delivery into the systemic circula tion. Insulin
(5.0 IU/kg iv) was administered to Dn followed by infusion with an
average rate of 0.95 +/- 0.17 IU x kg-1 x min-1 (n=6), and this
served as the hepatic hypoglycemic group. Saline was similarly
administered to Dn, which served as the normoglycemic control group.
In the hepatic hypoglycemic group, aortic and vena caval Glc levels
in Dn, which represent Glc concentrations entering the liver of Rc,
decreased from 129.9 +/- 7.1 and 122.5 +/- 7.8 mg% to 44.6 +/- 6.1
and 38.0 +/- 5.9 mg% (P<0.05) 45 min after insulin
administration, respectively. During this regional hepatic
hypoglycemia in Rc, the systemic glycemia being kept within a normal
range, adrenal epinephrine and norepinephrine output increased from
245.5 +/- 55.8 and 39.1 +/- 9.9 ng/min to 618.9 +/- 180.4 and 134.3
+/- 52.7 ng/min (P<0.05), respectively. By contrast, aortic Glc
and insulin levels in Dn of the normoglycemic control group remained
unchanged, as did adrenal epinephrine and norepinephrine output in
Rc. The results indicate that the regional hepatic hypoglycemia can
significantly increase adrenal catecholamine secretion even during
systemic (central) normoglycemia. The study suggests that the hepato
-adrenal Glc counterregulatory reflex may be functionally implicated
in insulin-induced hypoglycemia.
Received 16 December 1994; accepted in final form 15 December
1995.
APS Manuscript Number R712-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 22 January 96