title: Expression of cholecystokinin forms by medullary thyroid cancer.
abstract: 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 1-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.
authors.affiliation: Department of Surgery, University of Texas Medical Branch, Galveston 77550.
authors.forename: G J
authors.initials: GJ
authors.lastname: Poston
authors.forename: E J
authors.initials: EJ
authors.lastname: Draviam
authors.forename: P K
authors.initials: PK
authors.lastname: Seitz
authors.forename: S
authors.initials: S
authors.lastname: Rajaraman
authors.forename: R W
authors.initials: RW
authors.lastname: Alexander
authors.forename: C W
authors.initials: CW
authors.lastname: Cooper
authors.forename: C M
authors.initials: CM
authors.lastname: Townsend
authors.forename: J C
authors.initials: JC
authors.lastname: Thompson
mesh_terms: D000818:Animals; D002116:Calcitonin / Q000097:blood; D002118:Calcium / Q000097:blood; D002455:Cell Division; D002766:Cholecystokinin / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D007150:Immunohistochemistry; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013964:Thyroid Neoplasms / Q000097:blood / Q000378:metabolism* / Q000473:pathology
chemical_list: D002116:Calcitonin; D002766:Cholecystokinin; D002118:Calcium