AJP - Regulatory, Integrative and Comparative Physiology, Vol 232, Issue 1 66-R72, Copyright © 1977 by American Physiological Society
Glucose turnover in kelp bass (Paralabrax sp.): in vivo studies with [6-3H,6-14C]glucose
K. Bever, M. Chenoweth and A. Dunn
[6-3H,6-14C]glucose was injected via an indwelling arterial cannula in
free-swimming, fed, and fasted kelp bass to determine hepatic glucose
production, peripheral glucose uptake, minimal glucose mass, mean transit
time, and the percent of carbon recycling under the two different
nutritional states. Mean plasma glucose levels remained unchanged in fed
and fasted fish (48+/-8 vs. 43+/-8 mg/100 ml). During steady-state
conditions, glucose replacement rates of fed and fasted fish determined
with [6-3H]glucose are similar (0.035+/-0.006 vs. 0.025+/-0.003 mg/min per
100 g) and do not differ from rates determined with [6-14C]glucose
(0.035+/-0.005 vs. 0.026+/-0.002). The minimal glucose masses and the mean
transit tim-s determined with both isotopes are also similar suggesting
that plasma glucose levels and glucose turnover are maintained in fish
fasted up to 40 days with no apparent increase in carbon recycling.
Nonsteady-state isotope experiments suggest that these fish can alter rates
of hepatic glucose production and peripheral uptake in response to hyper-
and hypoglycemia.
