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Biology of Reproduction, Vol 21, 325-330, Copyright © 1979 by Society for the Study of Reproduction
1 Department of Biology,
Program in Physiology,
University of Houston,
Houston, Texas 77004 Selective luminal perfusion was utilized to characterize a sugar transport mechanism on the
uterine surface in estrogen primed ovariectomized adult rats. After a 30 second luminal perfusion/
incubation with a dual label system (10 µCi/ml at 1.0 mM final concentration of each compound),
ethanol extractable [14C]-D-mannitol and [3H]-3-0-methyl-D-glucose (3-0-MG) were employed to
estimate diffusion and total sugar uptake, respectively. The transport component of [3H]-3-0-MG
uptake was calculated as the difference between these 2 parameters. The carrier mechanism for
3-0-MG was observed to move the sugar faster than by diffusion, was inhibited by D-glucose (but
not by D-fructose or D-mannitol) and was insensitive to ouabain. Thus, this sugar uptake mechanism is probably one of facilitative transport. The interaction between amino acid (
-aminoisobutyric acid = AIB) and sugar transport also
was studied. Whereas AIB exerted no effect on [3H]-3-0-MG transport, high concentrations of
3-0-MG stimulated AIB transport, inhibition of efflux resulting in apparent stimulation of influx.
Since D-glucose did not exert a similar effect, the mechanism of 3-0-MG inhibition was considered
an interference with D-glucose utilization by metabolic enzymes and, hence, an indirect effect on
the energy dependent AIB efflux transport step.
Accepted on May 12, 1979
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