Abstract
In order to study hormone-dependent transport properties of VIP-sensitive colonic crypt cells were prepared using chelators and mechanical forces. Thymidine kinase activities in crypt cells and absorptive cells were 77±8 and 9±2 nmol/min/mg protein respectively. Hormone sensitivity was shown by a dose-dependent increase of cAMP levels up to 18-fold over basal with 10−6M VIP. From this preparation apical membranes were isolated by standard procedures. Membrane purity was assessed by electron microscopy and marker enzyme assays: In the final membrane preparation increase of relative specific activity (nmol/min/mg protein) - as compared to the intact cells – was 10-fold for alkaline phosphatase, 2-fold for Na–K–ATPase. Succinate dehydrogenase was decreased by 50%.
Conclusions: 1.Thymidine kinase concentrat ion in isolated colonic crypt cells is 8-fold higher than in absorptive cells. 2.This preparation is VIP-sensitive. 3. Apical crypt cell membranes were partially purified (ALP: 10-fold) with only minor contamination with basolateral membranes and mitochondria.
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Walther, S., Heinz-Erian, P., Roscher, A. et al. ISOLATION OF APICAL MEMBRANES FROM HORMONE-SENSITIVE RAT COLONIC CRYPT CELLS. Pediatr Res 26, 280 (1989). https://doi.org/10.1203/00006450-198909000-00098
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DOI: https://doi.org/10.1203/00006450-198909000-00098
