Long-term stimulation of cAMP production in LLC-PK1 pig kidney epithelial cells by salmon calcitonin or a photoactivatable analogue of vasopressin

David A. Jans, Ewa L. Gajdas, Christa Dierks-Ventling, Brian A. Hemmings, Falk Fahrenholz

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Abstract

A photoreactive analogue of vasopressin, [1-(3-mercapto)propionic acid, 8-(N6-4-azidophenylamidino)lysine]-vasopressin, was compared to salmon calcitonin and [8-arginine]-vasopressin with respect to stimulation of cAMP synthesis in the LLC-PK1 pig kidney epithelial cell line. Without photoactivation, the vasopressin analogue-elicited responses were identical to those induced by vasopressin, in that cAMP synthesis returned to the basal, unstimulated level about 4 h after hormonal treatment. In contrast, the levels of activation of cAMP-dependent protein kinase induced by salmon calcitonin returned to basal approx. 12 h after hormone addition. When activated by ultraviolet irradiation, the vasopressin analogue induced 'permanent' stimulation of adenylate cyclase, whereby cAMP production could be detected even 12.5 h after treatment. Both salmon calcitonin and the photoactivated vasopressin analogue inhibited growth of LLC-PK1 cells, in contrast to vasopressin or the nonactivated analogue. Growth inhibition appeared to be a consequence of the prolonged stimulation of adenylate cyclase. This conclusion was supported by the fact that a LLC-PK1 cell mutant in cAMP-dependent protein kinase was resistant to growth inhibition by salmon calcitonin and activated vasopressin analogue. The results imply that the cAMP-dependent protein kinase is the mediator of the hormone-stimulated growth inhibition.

Original languageEnglish
Pages (from-to)392-400
Number of pages9
JournalBBA - Molecular Cell Research
Volume930
Issue number3
DOIs
Publication statusPublished - 1 Oct 1987
Externally publishedYes

Keywords

  • Adenylate cyclase
  • Calcitonin
  • cyclic AMP production
  • Enzyme activity ratio
  • Protein kinase
  • Vasopressin

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