Expression of cholecystokinin forms by medullary thyroid cancer

✍ Scribed by G. J. Poston; E. J. Draviam; Patricia K. Seitz; S. Rajaraman; R. W. Alexander; C. W. Cooper; C. M. Townsend JR.; J. C. Thompson

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: French
• Weight: 498 KB
• Volume: 48
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910480510

✦ Synopsis

We have studied the production and release of cholecystokinin (CCK) forms by rat medullary thyroid cancer (MTC) in vivo. MTC cells were inoculated S.C. into 8 Wag-Rij rats. One month later, after i.v. injection of calcium plasma levels of CCK, calcitonin and tissue contents of gastrin and calcitonin were determined by radioimmunoassay (RIA), immunocytochemistry, and high-pressure liquid chromatography (HPLC). The tumors were passed 4 times to 8 rats in I -month intervals fasting levels of CCK in control rats were unaffected by calcium stimulation, and in tumor-bearing rats, plasma CCK was elevated in 3 out of 4 passages, falling to normal levels at the end of passage 4. Hypercalcemia had no effect on plasma levels of CCK in tumor-bearing rats, but did stimulate the release of calcitonin in both control and some tumor-bearing rats in later passages. CCK-8 sulfate was found in all 4 tumor passages but not CCK-33/39. We conclude that rat MTC synthesizes and releases CCK-8, but unlike calcitonin, release of CCK appears unresponsive to calcium stimulation.

4 T ~

whom correspondence and reprint requests should be addressed.