ISSN:
0091-7419
Keywords:
cyclic AMP
;
permeability
;
renal medulla
;
vasopressin
;
microtubules
;
microfilaments
;
Life Sciences
;
Molecular Cell Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Vasopressin-stimulated cyclic AMP content and the uptake of 3H2O and 22Na into canine renal medullary slices were measured. Cyclic AMP was increased threefold by 9 × 10-9M vasopressin in isotonic (290 mOsm/kg H2O) Krebs-Ringers bicarbonate. A significant increase in vasopressin-stimulated 3H2O uptake began at 2.75 min after hormone addition and lasted until 5.00 min. Colchicine (1 × 10-5 M) inhibited the vasopressin- stimulated 3H2O uptake. This effect required a minimum preincubation period of 30-40 min in colchicine-containing medium. Colchicine had no effect on basal or vasopressin-stimulated cyclic AMP (10 mM). Lumicolchicine (10-5M) had no effect on either vasopression- or dibutyryl cyclic AMP-stimulated 3H2O uptake. 14 C-colchicine bound predominantly to the cytosol fraction enriched in microtubules, while virtually no binding was observed on plasma membranes. Loght-microscopic examinations of cross sections of tissue slices showed that a majority of vasopressin-treated collecting tybulels and some control tubules had occluded lumens. Colchicine-treated cells, in the presence of vasopressin, had open lumens indicating a blockage of the vasopressin-induced water transport. Cells treated with cytochalasin B (1 μgm/ml) also had open lumens in the presence of vasopressin. Cytochalasin B also blocked vasopressin and dibutyryl cyclic AMP-stimulated 3H2O uptake into collecting duct cells but had no effect on vasopressin stimulated cyclic AMP levels. It was concluded that microtubules and possibley microfilaments are involved in the subcellular mechanism by which vasopresssin increases the permeability of the collecting duct to water.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jss.400050409
