Pituitary and adrenals are required for the hyperglycemic reflex
initiated by stimulation of the carotid body receptors with
cyanide..
Alvarez-Buylla, Ram[acute]on, Elena Alvarez-Buylla, Her[acute]on
Mendoza, Sergio A. Montero, and Arturo Alvarez-Buylla.
Centro Universitario de Investigaciones Biom[acute]edicas,
Universidad de Colima, Colima, Col., M[acute]exico, Departamento de
Fisiolog[acute]ia, Biof[acute]isica y Neurociencias, CINVESTAV,
M[acute]exico, Fac. de Medicina, Universidad Aut[acute]onoma de
Tamaulipas, M[acute]exico, and Rockefeller University, New York, NY,
U.S.A.
APStracts 3:0325R, 1996.
We have previously shown that stimulation of carotid body receptors
(CBR) with sodium cyanide (NaCN) elicits a rapid hyperglycemic
reflex. Here we explore whether the pituitary and adrenals, two
glands involved in glucose homeostasis, are necessary for this
reflex. Experiments were performed in anesthetized rats that were
artificially ventilated. Measurements of hepatic venous-arterial
glucose difference indicated that CBR stimulation with a bolus of 5
[mu]g/100 g NaCN, produced an immediate increase in the output of
glucose by the liver. The same dose of NaCN failed to increase
hepatic output of glucose in rats with bilateral adrenalectomy or in
rats one week after surgical removal of neurohypophysis (NHX). Reflex
glucose output by the liver was maintained after adenohypophysectomy
(AHX), or in adrenalectomized rats after adrenal autotransplantation
to epiplon. Measurements of epinephrine in plasma and in the grafted
adrenal tissue showed that the adrenal autograft can store and
secrete catecholamines. Immunocytochemical observations indicated
that the grafted adrenals retain medullary cells. These results
indicate that neurohypophysis and adrenals are necessary for the
hyperglycemic reflex initiated by CBR stimulation with NaCN, and that
the participation of these two organs in this reflex is probably
humoral.
Received 4 March 1996; accepted in final form 23 August 1996.
APS Manuscript Number R137-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996