Effect of arterially infused catecholamines and insulin on plasma glucose and free fatty acids in carp.
Common carp (Cyprinus carpio L.), kept at 20 degrees 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 microgram.kg-1.min-1 for epinephrine (Epi), 2 micrograms.kg-1.min-1 for norepinephrine (NE), and 1.33 micrograms.kg-1.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.
Van Raaij
M T
MT
Department of Biology, Gorlaeus Laboratories, State University of Leiden, The Netherlands.
van den Thillart
G E
GE
Hallemeesch
M
M
Balm
P H
PH
Steffens
A B
AB
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002347:Carps / Q000097:blood*; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D006854:Hydrocortisone / Q000097:blood; D007269:Injections, Intra-Arterial; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood / Q000494:pharmacology*; D009994:Osmolar Concentration
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine