Membrane transport in synchronized ehrlich ascites tumor cells: Uptake of amino acids by the A and L system during the cell cycle

✍ Scribed by Joseph T. Tupper; Barry Mills; Flavia Zorgniotti

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 769 KB
• Volume: 88
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1040880110

✦ Synopsis

Using the double thymidine block technique, Ehrlich ascites tumor cells (ELD) carried i n continuous spinner culture have been synchronized. Simultaneous monitoring of :tH-thymidine incorporation, cell number and mitotic index yielded a cell cycle time of approximately 13.5 hours. This is composed of an S period of 3-4 hours, G, of 6-8 hours and M of 1-2 hours.

No appreciable G I is present.

Ehrlich cells synchronized i n this manner were used to investigate the characteristics of two neutral amino acid transport systems during progression through the cell cycle. Unidirectional influx via the Na-dependent system A was studied using CII-alpha-aminoisobutyrate (AIB) as substrate. The Naindependent system L was monitored using 'rH-leucine and IGcycloleucine as substrates. Transport by the A system was minimal i n M and early S. It underwent a three-fold increase during late S and early G,. In mid G, the transport via this system rapidly dropped and remained low again through M and early