Cholecystokinin (CCK) Receptor and CCK Gene Expression in Human Pituitary Adenomas and in vitro Effects of CCK Peptides on GH and Gonadotrophin Secretion

Abstract

There is growing evidence that cholecystokinin (CCK) affects growth and differentiation of anterior pituitary cells, via the CCK-B receptor. The possibility of an autocrine / paracrine role for CCK to modulate hormone secretion in human pituitary tumour cells is demonstrated here by RT-PCR and direct sequencing. In support of this conclusion, a neutralising antibody against the CCK peptide exhibited a dose dependent inhibition of hormone secretion by functionless pituitary adenomas. Total RNA was extracted from human pituitary adenomas, reverse transcribed into cDNA and subjected to PCR using primers specific for the gene for CCK, CCK-A and CCK-B receptors. PCR bands of the predicted length were observed in all tumours using human CCK gene and CCK-B receptor primers. Restriction digestion and direct sequence analysis provided further evidence that they represented both the human CCK peptide along with the CCK-A and/B receptor mRNA. CCK-33 and CCK octapeptide sulphate (CCK-8s) both powerfully stimulated phosphatidylinositol hydrolysis, providing evidence for functional activity of the CCK-A and/B receptors. A direct stimulatory effect of CCK peptides on both LH and FSH secretion is reported for the first time, whereas stimulatory effects on GH were blocked by antagonists to CCK. These results may indicate an autocrine role for CCK in the functioning and perhaps development of human pituitary tumours.

Key words

CCK - CCK antagonists - pituitary adenomas - GH - gonadotrophins - autocrine

References

• 1 Ivy AC, Oldberg E. Hormone mechanism for gallbladder contraction and evacuation.  Am J Physiol. 1928;  86 599-613
• 2 Vanderhaegen JJ, Signeau JC, Gepts W. New peptide in vertebrate CNS reacting with antigastrin antibodies.  Nature. 1975;  257 604-605
• 3 Dockray GJ. Immunochemical evidence of cholecystokinin-like peptides in brain.  Nature. 1976;  264 586-570
• 4 Rehfeld JF. Immunochemical studies on cholecystokinin. II. Distribution and molecular heterogeneity in the central nervous system and small intestine of man and dog.  J Biol Chem. 1978;  253 4022-4030
• 5 Larsson L, Rehfeld JF. Localization and molecular heterogeneity of cholecystokinin in the central and peripheral nervous system.  Brain Res. 1979;  165 201-218
• 6 Noble F, Wank SA, Crawley JN, Bradwejn J, Seroogy KB, Hamon M, Roques BP. International union of pharmacology. XXI. Structure, distribution, and functions of cholecystokinin receptors.  Pharmacol Rev. 1999;  51 745-781
• 7 Malesci A, Straus E, Yalow RS. Cholecystokinin-converting enzymes in brain.  Proc Natl Acad Sci USA. 1980;  1 597-599
• 8 Straus E, Yalow RS. Species specificity of cholecystokinin in gut and brain of several mammalian species.  Proc Natl Acad Sci USA. 1978;  75 486-489
• 9 Wank SA, Pisegna JR, Weerth A. Brain and gastrointestinal receptor family: Structure and functional expression.  Proc Natl Acad Sci USA. 1992;  89 8601-8695
• 10 Saito A, Sankaran H, Goldfine ID, Williams JA. Cholecystokinin receptors in the brain: characterization and distribution.  Science. 1980;  208 1155-1156
• 11 Moran TH, Robinson PH, Goldrich MS, MacHugh PR. Two brain cholecystokinin receptors: implications for behavioral actions.  Brain Res. 1986;  362 175-189
• 12 Morley JE, Melmed S, Briggs J, Carlson HE, Hershman JM, Solomon TE, Lamers C, Damassa A. Cholecystokin octapeptide release growth hormone from the ppituitary in vitro.  Life Sci. 1979;  25 1201-1206
• 13 Smith AJ, Freedman SB. CCK-B receptor-mediated stimulation of polyphosphoinositide turnover in GH3 pituitary cells in response to cholecystokinin and pentagastrin.  Life Sci. 1996;  11 883-895
• 14 Vijayan E, Samson WK, MacCann SM. In vivo and in vitro effects of cholecystokinin on gonadotrophin, prolactin, growth hormone and tyrotrophin release in the rat.  Brain Res. 1979;  172 295-302
• 15 Malarkey WB, O'Dorisio TM, Kennedy M, Cataland S. The influence of vasoactive intestinal polypeptide and cholecystokinin on prolactin release in rat and human monolayer cultures.  Life Sci. 1981;  28 2489-2495
• 16 Calogero AE, Nicolosi AMG, Moncada ML, Coniglione F, Vicari E, Polosa P, D'Agata R. Effects of cholecystokinin octapeptide on the hypothalamic-pituitary-adrenal axis function and on vasopressin, prolactin and growth hormone release in humans.  Neuroendocrinology. 1993;  58 71-76
• 17 Imura H, Kato, Katakami H, Matsushita N. Effects of CNS peptides on hypothalamic regulation of pituitary secretion.  Adv Biochem Psychopharmacol. 1981;  28 557-570
• 18 Hashimoto R, Kimura F. Inhibition of gonadotrophin secretion induced by cholecystokin implants in the media preoptic area by the dopamine receptor blocker, pimozide, in the rat.  Neuroendocrinology. 1986;  42 32-37
• 19 Kawakami M, Arita J, Kimura F, Hayashi R. The stimulatory roles of cholecystokinin and acetylcholine in the regulation of gonadotropin release in ovariectomized estrogen-primed rats.  Endocrinol Jpn. 1979;  26 275-284
• 20 Adams EF, Lei T, Buchfelder M, Petersen B, Fahlbush R. Biochemical characterisation of human pituitary somatotrophinomas with and without gsp mutations: in vitro cells culture studies.  J Clin Endocrinol Metab. 1995;  80 2077-2081
• 21 Adams EF, Lei T, Buchfelder M, Bowers CY, Fahlbush R. Protein kinase C-dependant growth hormone releasing peptides stimulate cyclic adenosine 3',5'-monophosphate production by human pituitary somatotrophinomas expressing gsp oncogenes: evidence for cross-talk between transduction pathways.  Mol Endocrinol. 1996;  10 434-443
• 22 Green AD, Harris GW. The neurovascular link between the neurohypophysis and adenohypophysis.  J Endocrinol. 1947;  5 136-145
• 23 Adams EF, Brajkovich IE, Mashiter K. Hormone secretion by dispersed cell cultures of human pituitary adenomas: effects of theophylline, thyrotrophin-releasing hormone, somatostatin and 2-bromo-alpha-ergocryptine.  J Clin Endocrinol Metab. 1979;  49 120-126
• 24 Innis RB, Snyder SH. Distinct cholecystokinin receptors in brain and pancreas.  Proc Natl Acad Sci USA. 1980;  11 6917-6921
• 25 Schreihofer DA, Golden GA, Cameron JL. Cholecystokinin (CCK)-induced stimulation of luteinizing hormone (LH) secretion in adult male rhesus monkeys: examination of the role of CCK in nutritional regulation of LH secretion.  Endocrinology. 1993;  132 1553-1560
• 26 Smith AJ, Patel S, Freedman SB. Characterisation of CCK_B receptor on GH3 pituitary cells: receptor activation in linked to Ca²⁺ mobilisation.  Eur J Pharmacol. 1994;  267 215-223
• 27 Mayo KE, Godfrey PA, Suhr ST, Kulik DJ, Rahal JO. Growth hormone-releasing hormone: synthesis and signalling.  Recent Prog Horm Res. 1995;  50 35-37
• 28 Malagon MM, Luque RM, Ruiz-Guerrero E, Rodriguez-Pacheco F, Garcia-Navarro S, Casanueva FF, Gracia-Navarro F, Castano JP. Intracellular signaling mechanisms mediating ghrelin-stimulated growth hormone release in somatotropes.  Endocrinology. 2003;  12 5372-5380
• 29 Shulkes A, Baldwin GS. Biology of gut cholecystokinin and gastrin receptors.  Clin Exp Pharmacol Physiol. 1997;  24 209-216
• 30 Xu Y, Kaji H, Okimura Y, Matsui T, Abe H, Chihara K. Paracrine stimulation of cell growth by cholecystokinin/gastrin through cholecystokinin-B receptor on GH₃ cells in vitro.  Neuroendocrinology. 1996;  64 280-285
• 31 Kaufmann R, Henklein P, Nowak G. CCKB receptor activation results in increased [3H] thymidine incorporation in rat glioma C6 cells.  Neuropeptides. 1995;  29 241-244
• 32 Kopin AS, Lee YM, MacBride EW, Miller LJ, Lu M, Lin HY, Kolakowski  LF, Beinborn M. Expression cloning and characterization of the canine parietal cell gastrin receptor.  Proc Natl Acad Sci U S A. 1992;  89 3605-3609
• 33 Gruszka A, Pawlikowski M, Kunert-Radek J. Anti-tumoral action of octreotide and bromocriptine on the experimental rat prolactinoma: anti-proliferative and pro-apoptotic effects.  Neuroendocrinol Lett. 2001;  5 343-348

Correspondence