Open AccessEffect of Storage of Reconstituted Recombinant Human Thyroid‐Stimulating Hormone (rhTSH) on Thyroid‐Stimulating Hormone (TSH) Response Testing in Euthyroid Dogs
Author(s) -
Roover K. De,
Duchateau L.,
Carmichael N.,
Geffen C.,
Daminet S.
Publication year - 2006
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/j.1939-1676.2006.tb01790.x
Subject(s) - medicine , vial , euthyroid , endocrinology , stimulation , hormone , thyroid , recombinant dna , thyroid stimulating hormone , trh stimulation test , thyrotropin releasing hormone , biochemistry , chemistry , gene
Bovine thyrotropin (bTSH) stimulation testing has long been considered the gold standard for diagnosis of canine hypothyroidism. Unfortunately, bTSH is no longer commercially available. Recently, the use of recombinant human thyrotropin (rhTSH) to perform thyroid‐stimulating hormone (TSH) stimulation testing in dogs was described. The cost of an rhTSH vial (1.1 mg) limits the practical use of this product. The study reported here was performed to determine the effects of storing rhTSH on the post‐TSH increase of serum total (TT 4 ) and free (FT 4 ) thyroxine concentrations during TSH stimulation testing in 12 euthyroid Beagles in a crossover trial. Three TSH tests with recombinant human thyrotropin (rhTSH; 91.5 μg IV) were performed on each dog during 3 different periods: 1 with freshly reconstituted rhTSH (fresh); 1 with rhTSH, reconstituted and stored at 4°C for 4 weeks (refrigerated); and 1 with rhTSH, reconstituted and frozen at‐20°C for 8 weeks (frozen). Blood samples for determination of TT 4 and FT 4 concentrations were collected before and 4 and 6 hours after rhTSH administration. There was no significant difference in TT 4 or FT 4 concentration after stimulation with fresh, refrigerated, and frozen rhTSH. Furthermore, there was no significant difference between TT 4 or FT 4 serum concentration observed 4 and 6 hours after rhTSH administration. In conclusion, reconstituted rhTSH can be stored at 4°C for 4 weeks and at‐20°C for 8 weeks without loss of biological activity, allowing clinicians to perform more TSH response tests per vial.