Effect of thyroidectomy on rat T-kininogen.
The thyroid state affects the inflammatory reaction; in general, thyroid hormones increase and hypothyroidism decreases the inflammatory response. T-kininogen is an acute phase protein that inhibits cysteine proteases. The influence of thyroidectomy and 3,5,3'-triiodothyronine (T3)-treatment of thyroidectomized animals was examined on rat plasma T-kininogen concentration. Thyroidectomy increased the T-kininogen level three- to fourfold. A single administration of 10 micrograms T3/100 g body wt in 7-wk postthyroidectomy rats decreased it by approximately 50%. Daily treatment with 0.5 micrograms T3/100 g body wt prevented the increases in T-kininogen. The modifications in plasma T-kininogen concentration were confirmed by high-performance liquid chromatography analysis of the plasma kinins released by trypsin. They demonstrated that T-kinin was greatly and bradykinin slightly increased after thyroidectomy and that T-kinin concentration in T3-treated thyroidectomized animals was almost restored to the control level. The ability of thyroidectomized animals to produce a higher plasma T-kininogen compared with euthyroid animals was further documented when T-kininogen production was stimulated by laparotomy. This procedure resulted in a fourfold increase in T-kininogen in thyroidectomized animals compared with controls. The increase of plasma T-kininogen level after thyroidectomy results from a more active synthesis of the protein, since liver slices from thyroidectomized rats synthesized T-kininogen at a rate about two times higher than normal rats. These data may account at least in part for the diminution of the inflammatory response observed after thyroidectomy.
Bouhnik
J
J
Pathologie Vasculaire et Endocrinologic Rénale, Institut National de la Santé et de la Recherche Médicale U36, Paris, France.
Savoie
F
F
Baussant
T
T
Michaud
A
A
Alhenc-Gelas
F
F
Corvol
P
P
D000818:Animals; D001920:Bradykinin / Q000031:analogs & derivatives / Q000097:blood; D007037:Hypothyroidism / Q000378:metabolism; D007700:Kinetics; D007704:Kininogens / Q000096:biosynthesis / Q000097:blood* / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D012016:Reference Values; D013965:Thyroidectomy; D014284:Triiodothyronine / Q000494:pharmacology
D007704:Kininogens; D014284:Triiodothyronine; C039065:T-kinin; D001920:Bradykinin