AJP - Gastrointestinal and Liver Physiology, Vol 259, Issue 6 998-1009, Copyright © 1990 by American Physiological Society
Feeding induces lipid accumulation and increased Na+ transport in in vitro Necturus antrum
M. J. Rutten, C. D. Moore, R. Delcore Jr and L. Y. Cheung
Veterans Administration Medical Center, Kansas City, Missouri 64128.
We investigated the effects of feeding on lipid accumulation and
transepithelial transport using in vitro Necturus gastric antral mucosae.
Antra from fed Necturi were examined for lipid accumulation using light,
fluorescence, histochemical, and electron microscopy. Ussing chambers were
used for measurement of potential difference (PD), transepithelial
resistance (Rt), short-circuit current (Isc), and unidirectional fluxes of
22Na+ and [3H]mannitol. Light microscopy of antra from 2-day postfed
animals showed many intracellular lipid granules in surface mucous
epithelial cells. These granules could be distinguished from other
intracellular organelles by their high affinity for osmium and the lipid
fluorescent probe Nile red. Glycoprotein cytochemical staining showed these
granules to be distinct from the epithelial cell mucous granules. Electron
microscopy showed the lipid granules to be part of a membranous reticular
network. Two-day postfed animals also had a approximately 3.5-fold increase
in amiloride-sensitive Isc and PD, a decrease in Rt, and an increased
luminal-to-serosal Na+ fluxes. Transepithelial [3H]mannitol fluxes were low
and remained unchanged in both fasted and 2-day postfed animals. After 2
days of feeding, the PD and Isc began to decrease followed by a secondary
increase in Rt. Feeding Necturi a corn oil diet did not induce the
appearance of either cellular lipid or alterations in Isc but produced a
transient increase in Rt. Our data show that feeding (goldfish) to Necturi
causes an increase in both lipid accumulation and amiloride-sensitive Na+
transport in gastric antral cells.
