Sympathoadrenal influence on glucose, FFA, and insulin levels in exercising rats.
The effects of sympathoadrenal manipulations on the exercise-induced alterations in blood glucose, plasma free fatty acids (FFA), and insulin were investigated in intact and adrenodemedullated rats. Exercise consisted of strenuous swimming against a countercurrent for 15 min. Before, during, and after swimming, blood samples were taken through a permanent heart catheter. Adrenodemedullation (Adm) markedly reduced the exercise-induced increase in both glucose and FFA. This effect was counteracted by intravenous infusion of epinephrine (E, 20 ng/min). Intravenous infusion of 50 ng E/min into Adm rats caused an exaggerated increase in glucose. In two additional experiments 1) specific adrenoceptor agonists and antagonists were administered to exercising intact and Adm rats, and 2) E or norepinephrine (NE; 20 ng/min) was infused into intact resting rats. The results suggest that E from the adrenal medulla directly affects glucose and insulin but not FFA concentrations in the blood. NE released from peripheral sympathetic nerve endings probably acts in two different ways: as neurotransmitter on liver and pancreas and as a hormone on adipose tissue.
Scheurink
A J
AJ
Department of Animal Physiology, State University of Groningen, Haren, The Netherlands.
Steffens
A B
AB
Bouritius
H
H
Dreteler
G H
GH
Bruntink
R
R
Remie
R
R
Zaagsma
J
J
D000313:Adrenal Medulla / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D007328:Insulin / Q000097:blood*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D010805:Physical Conditioning, Animal; D051381:Rats; D011919:Rats, Inbred Strains; D013564:Sympathetic Nervous System / Q000378:metabolism*
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D009638:Norepinephrine; D004837:Epinephrine