The effect of adrenaline pretreatment on the in vitro generation of 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine (reverse T3) in rat liver preparation

Horm Metab Res. 1984 Sep;16(9):471-4. doi: 10.1055/s-2007-1014822.

Abstract

The effects of adrenaline (A) on liver T3 and rT3 neogenesis from T4 were studied in Wistar rats. The animals were implanted subcutaneously either with A or placebo (P) especially coated tablets which linearly released the hormone. The serum A values 6 hrs after implantation of 7.5, 15.0 and 45.0 mg tablets were 6.5 +/- 1.31, 6.8 +/- 1.8 and 16.4 +/- 1.9 ng/ml, respectively vs 4.4 +/- 2.5 ng/ml seen in P pretreated group. The output rates of A were 0.11 (7.5 mg), 0.18 (15 mg) and 0.52 microgram/ml (45 mg). The pretreatment with A led to hyperglycemia and the "low T3 syndrome". Neogenesis of T3 from T4 in medium containing liver microsomes of P pretreated rats was 5.49 +/- 0.25 pmol of T3/mg protein/min and decreased in A pretreated rats to 3.82 +/- 0.17, 3.12 +/- 0.27 and 3.06 +/- 0.11 pmol of T3/mg of protein/min. Neogenesis of rT3 from T4 in microsomes from P group was 1.52 +/- 0.09 pmol rT3/mg protein/min and increased after A to 2.71 +/- 0.11, 2.60 +/- 0.21 and 2.21 +/- 0.34 pmol of rT3/mg protein/min thus showing no dose dependency. Enrichment of microsomes medium with cytosol either from P or A pretreated rats had no effect on T3 generation thus excluding effect of A on cytosolic cofactor. Although cytosol further increased rT3 neogenesis this was seen regardless of whether cytosol was obtained from A or P implanted rats. It is concluded that A decreases the activity of T4-5'-deiodinase in liver, and possibly increases the activity of T4-5-deiodinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Coenzymes / metabolism
  • Cytosol / enzymology
  • Epinephrine / pharmacology*
  • In Vitro Techniques
  • Iodide Peroxidase / metabolism
  • Liver / enzymology*
  • Male
  • Microsomes, Liver / enzymology
  • Rats
  • Rats, Inbred Strains
  • Thyroxine / metabolism*
  • Triiodothyronine / biosynthesis*
  • Triiodothyronine, Reverse / biosynthesis*

Substances

  • Coenzymes
  • Triiodothyronine
  • Triiodothyronine, Reverse
  • Iodide Peroxidase
  • Thyroxine
  • Epinephrine