VALIDATION OF AN EIA KIT FOR DETERMINATION OF TOTAL THYROID-HORMONES IN RAT SERUM - EFFECTS OF DIFFERENT ANESTHETICS

Two enzyme immunoassays for the quantitative determination of total th yroxine (T4) and total triiodothyronine (T3) in human serum were valid ated to measure total T4 and T3 in rat serum. The specificity, sensiti vity, detectability and reproducibility have been tested as well as th e effects of different anaesthetics (pentobarbital and a mixture of ke tamine and xylacine) on serum thyroid hormone levels. Hormones were qu antified, by means of a previously validated technique, 18 hours after surgery for the placement of a stem for blood extraction in conscious and freely moving animals. Thyroid serum levels, especially T3, were slightly lower in xylacine plus ketamine treated animals than in those treated with pentobarbital. The administration of glutamic acid, stim ulated the secretion of thyroid hormones, this effect appearing 30 min utes after its administration and it was independent of the anaestheti c used during the surgery for the cannula placement, although in pento barbital treated rats, the serum T3 level increase induced by glutamat e appears 60 minutes after the treatment.