Abstract
1. A study of the calcium equilibrium in isolated frog muscle has been attempted. 2. When sartorius muscles were immersed in Ca45 Ringer's solution, the surface phase took up the Ca45 in about 1 minute; the extracellular water space and connective tissue in about 30 minutes; and the intracellular space in about 300 minutes. 3. The percentages of total calcium in the whole muscle immersed in Ringer's solution was as follows: 10 per cent in the surface phase; 12 per cent in the extracellular water space; 17 per cent in the dry connective tissue; 24 per cent in the intracellular space; and 37 per cent as non-exchangeable calcium. 4. The exchange constants of isolated frog sartorius muscle to calcium has been determined. The flux of intracellular calcium in the steady state was approximately 0.8 mM/(liter hr). 5. It appears that there is a calcium pump pushing calcium out of the cell against an electrochemical gradient of about 4 cal./mM of calcium. However, since the flux is low, the maximum energy required per hour to pump calcium out of the cell against this high gradient is only about 2 cal./kg. muscle or about 1 per cent of the resting energy.
Full Text
The Full Text of this article is available as a PDF (817.5 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- FLASCHKA H., HOLASEK A. Eine neue Methode zur Bestimmung des Calciums im Blutserum. Hoppe Seylers Z Physiol Chem. 1951 Nov;288(4-6):244–249. [PubMed] [Google Scholar]
- LANSING A. I., ROSENTHAL T. B., KAMEN M. D. The effect of age on calcium binding in mouse liver. Arch Biochem. 1949 Jan;20(1):125–130. [PubMed] [Google Scholar]
- SOLOMON A. K. Equations for tracer experiments. J Clin Invest. 1949 Nov;28(6 Pt 1):1297–1307. doi: 10.1172/JCI102197. [DOI] [PMC free article] [PubMed] [Google Scholar]
- USSING H. H. Some aspects of the application of tracers in permeability studies. Adv Enzymol Relat Subj Biochem. 1952;13:21–65. doi: 10.1002/9780470122587.ch2. [DOI] [PubMed] [Google Scholar]