Inhibition of epidermal growth factor binding in rat pancreatic acini by palmitoyl carnitine: Evidence for Ca2+ and protein kinase C independent regulation

J. S. Brockenbrough, Murray Korc

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

D,L-Palmitoyl carnitine (PC), an inhibitor of protein kinase C, decreased [125I]epidermal growth factor (EGF) cell-associated radioactivity in rat pancreatic acini. H-7, another inhibitor of protein kinase C, failed to inhibit [125I]EGF binding. Palmitate, carnitine, acetylcarnitine, and 2-tetradecylglycidic acid methyl ester (a specific inhibitor of endogenous PC formation) did not alter [125I]EGF binding. PC conjugated to bovine serum albumin (PC-BSA) decreased [125I]EGF cell-associated radioactivity to the same extent as PC. Neither compound affected the distribution of cell-associated radioactivity into acid-resistant and acid-dissociable compartments. In contrast, cholecystokinin octapeptide (CCK8) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) markedly inhibited the distribution of [125I]EGF into the acid-resistant compartment. Proglumide, a competitive antagonist of CCK8, reversed the inhibitory action of CCK8 but not that of PC-BSA. PC-BSA did not inhibit [125I]insulin binding, and did not enhance amylase release, a Ca2+-mediated effect. Further, its inhibitory effect on [125I]EGF cell-associated radioactivity was not additive with the inhibitory effect of the calcium ionophore A23187. Both PC-BSA and H-7 inhibited Ca2+- and phospholipid-dependent kinase activity in soluble and particulate fractions when added to disrupted acini, but in the particulate compartment only when added to intact acini. These findings suggest that PC-BSA may regulate EGF binding via a novel mechanism that is independent of protein kinase C activation or Ca2+ mobilization.

Original languageEnglish (US)
Pages (from-to)1805-1810
Number of pages6
JournalCancer Research
Volume47
Issue number7
StatePublished - 1987
Externally publishedYes

Fingerprint

Carnitine
Epidermal Growth Factor
Protein Kinase C
Radioactivity
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
Acids
Proglumide
Acetylcarnitine
Sincalide
Calcium Ionophores
Palmitates
Calcimycin
Tetradecanoylphorbol Acetate
Amylases
Bovine Serum Albumin
Phospholipids
Esters
Phosphotransferases
Insulin

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Inhibition of epidermal growth factor binding in rat pancreatic acini by palmitoyl carnitine : Evidence for Ca2+ and protein kinase C independent regulation. / Brockenbrough, J. S.; Korc, Murray.

In: Cancer Research, Vol. 47, No. 7, 1987, p. 1805-1810.

Research output: Contribution to journalArticle

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