Metabolic and vascular effects of circulating endothelin-1 during
moderately heavy prolonged exercise.
Ahlborg, Gunvor, Eddie Weitzberg, Jan Lundberg.
Department of Clinical Physiology, Huddinge Hospital, and
Departments of Anestesiology and Intensive Care, Karolinska Hospital,
and Pharmacology, Karolinska Institute, Stockholm, Sweden.
APStracts 2:0067A, 1995.
The aims were to investigate (a) whether the suppressive effect of
endothelin-1 (ET-1) on splanchnic blood flow, arterial glucagon,
insulin and glucose as well as splanchnic glucose production at rest
is overcome or prevails during exercise (Study I) and (b) the
influence of exercise on circulating arterial ET-1 levels (Studies I
and II). In Study I, six healthy subjects performed 2 h of exercise
at 50% of their peak oxygen uptake on two occasions, preceded by
intravenous infusion of either physiological saline or ET-1 (4
pmol.kg-1.min-1). Blood specimens were taken from catheters in the
brachial artery and a central hepatic vein. The ET-1 levels rose 15
-fold during the infusion at rest. Splanchnic blood flow fell after
ET-1 (p<0.01) and remained unchanged during exercise. Splanchnic
glucose production was approximately 25% lower compared to control
exercise values during the whole exercise period (p<0.01). Neither
heart rate, arterial glucagon, insulin, catecholamines, renin,
glucose, lactate, nor glycerol levels differed from in the control
exercise. Splanchnic glycerol uptake was slightly lower (p<0.05
-0.01), but lactate uptake remained unchanged compared to controls.
The calculated gluconeogenesis from these substrates did not differ
from the corresponding control values. ET-1 levels rose approximately
two-fold in the control exercise during the initial 20 min (p<0.01).
Received 8 June 1994; accepted in final form 16 February 1995.
APS Manuscript Number A566-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 1 March 1995.