Use of recombinant human thyroid-stimulating hormone for thyrotropin-stimulation testing of euthyroid cats

Julie R. Stegeman Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824-1314.

Search for other papers by Julie R. Stegeman in
Current site
Google Scholar
PubMed
Close
 DVM
,
Peter A. Graham Department of Endocrinology Section, Animal Health Diagnostic Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824-1314.
Present address is North Western Laboratories, 23 Mains Ln, Poulton-Le-Fylde, Lancashire, UK FY6 7LJ.

Search for other papers by Peter A. Graham in
Current site
Google Scholar
PubMed
Close
 BVMS, PhD
, and
Joe G. Hauptman Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824-1314.

Search for other papers by Joe G. Hauptman in
Current site
Google Scholar
PubMed
Close
 DVM, MS

Abstract

Objective—To evaluate response of euthyroid cats to administration of recombinant human thyroid-stimulating hormone (rhTSH).

Animals—7 healthy cats.

Procedure—Each cat received each of 5 doses of rhTSH (0, 0.025, 0.050, 0.100, and 0.200 mg), IV, at 1-week intervals. Serum concentration of total thyroxine (TT4) and free thyroxine (fT4) was measured immediately before each injection (time 0) and 2, 4, 6, and 8 hours after administration of each dose.

Results—Overall TT4 response did not differ significantly among cats when administered doses were ≥ 0.025 mg. Serum TT4 concentrations peaked 6 to 8 hours after administration for all doses ≥ 0.025 mg. For all doses ≥ 0.025 mg, mean ± SEM TT4 concentration at 0, 6, and 8 hours was 33.9 ± 1.7, 101.8 ± 5.9, and 101.5 ± 5.7 nmol/L, respectively. For all doses ≥ 0.025 mg, mean fT4 concentration at 0, 6, and 8 hours was 38.7 ± 2.9, 104.5 ± 7.6, and 100.4 ± 8.0 pmol/L, respectively. At 8 hours, the fT4 response to 0.025 and 0.050 mg was less than the response to 0.100 and 0.200 mg. Adverse reactions after rhTSH administration were not detected.

Conclusions and Clinical Relevance—The TSH stimulation test can be performed in cats by IV administration of 0.025 to 0.200 mg of rhTSH and measurement of serum TT4 concentrations at time of injection and 6 or 8 hours later. Clinical validation of the TSH stimulation test would facilitate development of additional tests of thyroid gland function, such as a TSH assay. (Am J Vet Res 2003;64:149–152)

Abstract

Objective—To evaluate response of euthyroid cats to administration of recombinant human thyroid-stimulating hormone (rhTSH).

Animals—7 healthy cats.

Procedure—Each cat received each of 5 doses of rhTSH (0, 0.025, 0.050, 0.100, and 0.200 mg), IV, at 1-week intervals. Serum concentration of total thyroxine (TT4) and free thyroxine (fT4) was measured immediately before each injection (time 0) and 2, 4, 6, and 8 hours after administration of each dose.

Results—Overall TT4 response did not differ significantly among cats when administered doses were ≥ 0.025 mg. Serum TT4 concentrations peaked 6 to 8 hours after administration for all doses ≥ 0.025 mg. For all doses ≥ 0.025 mg, mean ± SEM TT4 concentration at 0, 6, and 8 hours was 33.9 ± 1.7, 101.8 ± 5.9, and 101.5 ± 5.7 nmol/L, respectively. For all doses ≥ 0.025 mg, mean fT4 concentration at 0, 6, and 8 hours was 38.7 ± 2.9, 104.5 ± 7.6, and 100.4 ± 8.0 pmol/L, respectively. At 8 hours, the fT4 response to 0.025 and 0.050 mg was less than the response to 0.100 and 0.200 mg. Adverse reactions after rhTSH administration were not detected.

Conclusions and Clinical Relevance—The TSH stimulation test can be performed in cats by IV administration of 0.025 to 0.200 mg of rhTSH and measurement of serum TT4 concentrations at time of injection and 6 or 8 hours later. Clinical validation of the TSH stimulation test would facilitate development of additional tests of thyroid gland function, such as a TSH assay. (Am J Vet Res 2003;64:149–152)

All Time Past Year Past 30 Days
Abstract Views 47 0 0
Full Text Views 730 610 167
PDF Downloads 109 73 4
Advertisement