ISSN:
1432-1424
Keywords:
exocrine glands
;
fluid and electrolyte secretion
;
cell volume regulation
;
Golgi complex
;
membrane recycling
;
stimulus-secretion coupling
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary To test the possibility that stimulation of secretion leads Na,K-ATPase to be recruited from cytoplasmic pools and inserted into basal-lateral plasma membranes, we surveyed the subcellular distributions of Na, K-ATPase in resting and stimulated fragments of rat exorbital lacrimal gland. After a two-dimensional separation procedure based on differential sedimentation and density gradient centrifugation, we defined sixdensity windows, which differ from one another in their contents of biochemical markers. The membranes equilibrating inwindow I could be identified as a sample of basal-lateral membranes; in resting preparations these membranes contained Na,K-ATPase enriched 16.6-fold with respect to the initial homogenates.Windows II throughVI contained various cytoplasmic membrane populations; these accounted for roughly 80% of the total recovered Na,K-ATPase activity. Thirty-minute stimulation with 10 μm carbachol caused a 1.4-fold increase (P〈0.05) in the total Na,K-ATPase content ofwindow I; this increase could be largely accounted for by a 1.7-fold decrease in the total Na,K-ATPase content ofdensity window V. Acid phosphatase activity also redistributed following stimulation, but it was recruited from a different source, and it was inserted into membranes equilibrating inwindows II andIII as well as into the membranes ofwindow I.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01925712
