Na+-K+ATPase distribution in frog and bovine lenses
作者:
AlvarezLawrence J.,
CandiaOscar A.,
GrilloneLisa R.,
期刊:
Current Eye Research
(Taylor Available online 1985)
卷期:
Volume 4,
issue 2
页码: 143-152
ISSN:0271-3683
年代: 1985
DOI:10.3109/02713688508999980
出版商: Taylor&Francis
数据来源: Taylor
摘要:
Na+-K+ATPase activity was measured in the capsule-epithelium and decapsulated frog and bovine lens. The decapsulated lens contained approximately 20% of the whole lens activity in the frog and 30% in the bovine. These values were measured from the aqueous homogenate of the entire decapsulated lens, an approach which may have underestimated the activity by diluting the ouabain-sensitive component in the preparation. Subsequent determinations were done on separate portions of superficial (2 to 3 mm) anterior-equatorial, and posterior bovine cortex. The activities per gram of tissue were enriched with respect to the values for the entire decapsulated bovine lens. These activities were further enriched by a sucrose density gradient centrifugation. The anterior-equatorial cortical segment contained 1.6 times the activity found in the capsule-epithelium. The posterior cortex had a much smaller but statistically significant level of Na+-K+ATPase. It is unlikely that the observed asymmetry of the anterior-equatorial segment with the posterior cortex is exclusively due to epithelial contamination for the result would require the adherence of 62% of the epithelium. Scanning electron micrographs of 6 decapsulated bovine lenses indicated an average contamination of about 9%. This asymmetry may have a physiological role in assisting the pump mechanism of the epithelium.
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