Involvement of 3′,5′-cyclic adenosine monophosphate in the increase of tyrosine hydroxylase activity elicited by cold exposure

A. Guidotti, B. Zivkovic, R. Pfeiffer, E. Costa

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

We studied the relationship between changes of 3′,5′-cyclic adenosine monophosphate (cAMP) and tyrosine hydroxylase (TH) activity in adrenal medulla of rats exposed to cold stress. Exposure of rats to 4° C produced a ten-fold increase of the cAMP content of adrenal medulla in about 30 min. This increase persisted for about one hour; the levels of cAMP returned to control value within 120 min in spite of the continued exposure to 4° C. In rats with monolaterally denervated (splanchnicotomized) adrenal, the exposure to 4° C produced only insignificant changes of cAMP concentration. During the exposure to 4° C we also observed an increase (about two times) of catecholamine turnover rate as measured by 3H-dopamine efflux from adrenal glands. This increased efflux persisted for 6 h of exposure to cold suggesting that the efflux of 3H-dopamine can increase without a simultaneous increase of cAMP concentrations. Exposure of rats to 4° C for two hour also increases (about two times) the TH activity as measured 24 h later. Exposure of the animals to 4° C for a time period longer than two hour (4 or 24 h) failed to produce further increases of TH activity. These results support the concept that the increase of cAMP concentrations in adrenal medulla may play a central role in initiating the chain of biochemical events modulating the synthesis of TH.

Original languageEnglish (US)
Pages (from-to)195-206
Number of pages12
JournalNaunyn-Schmiedeberg's Archives of Pharmacology
Volume278
Issue number2
DOIs
StatePublished - Jun 1 1973

Keywords

  • Adrenal Medulla
  • Catecholamine Turnover
  • Cold Exposure
  • Tyrosine Hydroxylase
  • cAMP

ASJC Scopus subject areas

  • Pharmacology

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