Amiodarone: influence of the route of administration on thyroid status and cardiac beta-adrenoceptors in the rat.
The influence of 2 different routes of amiodarone (AMIO) administration, oral gavage (OG) and subcutaneous injection (SC), on the density of cardiac beta-adrenoceptors (Bmax), hepatic type I 5' iodothyronine deiodinase (5' DI) and thyroid hormone serum concentrations was studied. Compared with respective control values, AMIO treatment (50 mg/kg per day, 7 days) via both OG and SC routes significantly lowered Bmax (OG: 14.6 +/- 1.92 vs 18.2 +/- 1.03 fmol/mg and SC: 16.6 +/- 2.34 vs 19.1 +/- 2.05 fmol/mg) and 5' DI activity (from 409 to 85 and 340 to 47 fmol I-/mg per min, respectively). The SC route induced a fall in thyroid secretion and a generalized hypothyroidism (decreased serum FT4 and FT3, inhibition of body weight gain. The OG route did not modify thyroid secretion. These results demonstrated that the effects on cardiac beta-receptor density in the SC group might be due to the generalized hypothyroidism and that AMIO produced its specific cardiac effects only after oral route medication, suggesting that the oral route is the best choice for studying AMIO cardiac effects on beta-receptor density.
Yin
Y L
YL
Laboratoire de Pharmacologie Clinique et Expérimentale, Faculté de Médecine, Université Paris-Nord, Bobigny, France.
Nicolas
P
P
Vassy
R
R
Uzzan
B
B
Pussard
E
E
Berdeaux
A
A
Perret
G
G
D000284:Administration, Oral; D000638:Amiodarone / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D007279:Injections, Subcutaneous; D007453:Iodide Peroxidase / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D008297:Male; D009206:Myocardium / Q000737:chemistry*; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000032:analysis*; D013963:Thyroid Hormones / Q000097:blood*
D011943:Receptors, Adrenergic, beta; D013963:Thyroid Hormones; D007453:Iodide Peroxidase; D000638:Amiodarone