Biomaterial Database

Low-dose glucocorticoids stimulate electroneutral NaCl absorption in rat colon. 1989

C P Bastl, and G Schulman, and E J Cragoe

Department of Medicine, Temple University Health Sciences Center, Philadelphia, Pennsylvania 19140.

Glucocorticoids, not aldosterone, may regulate basal colonic NaCl transport. Aldosterone induces spironolactone-inhibitable, amiloride-inhibitable conductive Na absorption but basal transport is electroneutral and amiloride and spironolactone resistant. We examined in vivo the Na absorptive pathway induced by glucocorticoid receptor specific doses of glucocorticoid using various amiloride analogues. Doses of dexamethasone sufficient to co-occupy aldosterone receptors produced amiloride-sensitive Na absorption in proximal and distal colon. Low doses of dexamethasone or the specific glucocorticoid RU26988 markedly stimulated Na absorption but did so by an amiloride-resistant mechanism. The Na-H antiport inhibitor, 5-N-ethyl-N-isopropylamiloride (NENIA) eliminated glucocorticoid-induced Na and Cl absorption without changing transmural potential difference (PD) in proximal and distal colon (Ki = 0.7 x 10(-7) M). NENIA had no effect on aldosterone-induced transport. NENIA (10(-5) M) almost eliminated Na absorption in adrenal intact animals if infused early in the experimental protocol. With time, NENIA resistance developed, corresponding with the previously documented rise in endogenous aldosterone. Thus glucocorticoids induce an electroneutral Na absorptive pathway that may be the luminal Na-H antiport, suggesting that glucocorticoids regulate adrenal-dependent electroneutral Na absorption in rat colon.

UI	MeSH Term	Description	Entries
D007408	Intestinal Absorption	Uptake of substances through the lining of the INTESTINES.	Absorption, Intestinal
D008297	Male		Males
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D002712	Chlorides	Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.	Chloride,Chloride Ion Level,Ion Level, Chloride,Level, Chloride Ion
D003106	Colon	The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.	Appendix Epiploica,Taenia Coli,Omental Appendices,Omental Appendix,Appendices, Omental,Appendix, Omental
D003907	Dexamethasone	An anti-inflammatory 9-fluoro-glucocorticoid.	Hexadecadrol,Decaject,Decaject-L.A.,Decameth,Decaspray,Dexasone,Dexpak,Hexadrol,Maxidex,Methylfluorprednisolone,Millicorten,Oradexon,Decaject L.A.
D000315	Adrenalectomy	Excision of one or both adrenal glands. (From Dorland, 28th ed)	Adrenalectomies