Year-end Sale % OFF 
Abstract
Microsomes isolated from canine submandibular glands were examined for ATP-dependent calcium accumulation and calcium release. Calcium uptake (10 to 20 nmoles per min per mg protein at 37 °C) was linear with time up to 20 min and with the amount of microsomal protein in the range of 15 to 200 μg/ml of incubation medium. Of the nucleotide triphosphates tested, only adenosine triphosphate (ATP) supported calcium accumulation. Ruthenium red and ethacrynic acid, at concentrations of 90 μg/ml and 10 −4 M respectively, almost completely inhibited calcium uptake. Metabolic inhibitors such as 2,4 dinitrophenol, azide and oligomycin only partially affected microsomal calcium uptake. Incubation of prelabelled microsomes in a calcium-free solution resulted in the release of calcium at a rate of 0.025/min. The rate was decreased at 0 °C and by inclusion of 4.5 mM ATP in the medium. Addition of 2 mM calcium or removal of magnesium also reduced release. Ruthenium red at a concentration that decreased calcium uptake by greater than 90 per cent did not affect calcium outflow; whereas ethacrynic acid (5 × 10 −4M) induced a significant increase in calcium loss.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
