Effect of arterially infused catecholamines and insulin on plasma glucose and free fatty acids in carp
Van Raaij, M.T.; van den Thillart, G.E.; Hallemeesch, M.; Balm, P.H.; Steffens, A.B.
American Journal of Physiology 268(5 Pt 2): R1163-R1170
1995
ISSN/ISBN: 0002-9513 PMID: 7771575 Document Number: 446826
Common carp (Cyprinus carpio L.), kept at 20 degree C, were fitted with an indwelling PE-50 cannula in the dorsal aorta. Hormones dissolved in Ringer saline were arterially infused at a rate of 1 mu-g cntdot kg-1 cntdot min-1 for epinephrine (Epi), 2 mu-g cntdot kg-1 cntdot min-1 for norepinephrine (NE), and 1.33 mu-g cntdot kg-1 cntdot min-1 for insulin. Infusion of bovine insulin in carp resulted in a long lasting (24 h) decrease of plasma free fatty acids (FFA; -0.41 +- 0.06 mM) and glucose levels (-3.14 +- 0.25 mM) compared with preinfusion levels at t = 0. Both Epi and NE induced a marked hyperglycemia although Epi was more potent (+8.2 +- 0.9 and +6.9 +- 0.8 mM, respectively). Plasma FFA levels increased by 0.25 +- 0.03 mM compared with preinfusion levels on Epi infusion. In contrast, during NE infusion, plasma FFA levels decreased significantly by -0.21 +- 0.03 mM. Plasma insulin titers did not significantly change during infusion of NE or Epi. It is concluded that the ratio of NE to Epi is the major factor that determines the effect of catecholamines on plasma FFA levels in carp. These results may explain species-dependent different effects of hypoxia on FFA metabolism in fish.