Calcium transport by basal lateral membrane vesicles from rat small intestine decreases with age
| Autor: | Susan B. Porter, H. James Armbrecht, William G. Doubek |
|---|---|
| Rok vydání: | 1988 |
| Předmět: |
Male
Aging medicine.medical_specialty Duodenum Biophysics Biological Transport Active chemistry.chemical_element Calcium ion transport Ileum In Vitro Techniques Calcium Biology Biochemistry Epithelium Basal (phylogenetics) Internal medicine Intestine Small medicine Animals Calcium metabolism Cell-Free System Vesicle Calcium-Binding Proteins Cell Membrane Vanadium Cell Biology Membrane transport Rats Inbred F344 Rats Kinetics Endocrinology medicine.anatomical_structure chemistry Oligomycins |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 944:367-373 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(88)90507-x |
| Popis: | There is a marked decrease in active Ca2+ transport by the rat small intestine with age, particularly between 2 and 12 months. Much evidence suggests that the active component of Ca2+ transport resides in the energy-dependent pumping of Ca2+ across the intestinal basal lateral membrane. Therefore, we have characterized Ca2+ uptake by basal lateral membrane vesicles isolated from young (2-3 month old) and adult (12-14 month old) rats. In vesicles from the proximal duodenum, ATP-dependent Ca2+ uptake was about 4-times greater in the young animal than in the adult. There were no age differences in Ca2+ uptake in the absence of ATP. In vesicles from the ileum, Ca2+ uptake was much less than in the duodenum. The age differences in the ileum were smaller, and ATP-dependent Ca2+ uptake in the young was only twice that seen in the adult. Osmotic lysis of duodenal vesicles reduced Ca2+ uptake to low levels in both age groups, indicating that most of the Ca2+ was being taken up into an osmotically active space. Kinetic studies of Ca2+ uptake showed that there was no change in the apparent affinity but a 5-fold decrease in the Vmax of the adult Ca2+ transport system compared to that of the young animal. This marked decrease in the capacity of basal lateral membrane vesicles to actively transport Ca2+ may contribute to the decline in intestinal Ca2+ absorption with age. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|