Format

Send to

Choose Destination
See comment in PubMed Commons below
J Am Vet Med Assoc. 1996 Jun 15;208(12):2004-8.

Effect of illness not associated with the thyroid gland on serum total and free thyroxine concentrations in cats.

Author information

1
Department of Veterinary Medicine, University of Glasgow Veterinary School, Bearsden, Scotland.

Abstract

OBJECTIVE:

To determine circulating concentrations and fate of total and free thyroxine (T4) in cats with various illnesses not associated with the thyroid glands (nonthyroidal illnesses).

DESIGN:

Prospective study.

ANIMALS:

98 cats with nonthyroidal illness and 50 clinically normal cats.

PROCEDURE:

Serum total T4 concentrations were measured by radioimmunoassay, and serum free T4 concentrations were measured by direct equilibrium dialysis. Free T4 fraction was calculated from these 2 values.

RESULTS:

Serum total T4 concentrations were significantly (P < 0.001) lower in sick cats (mean +/- SD, 17.18 +/- 8.14 nmol/L), compared with healthy cats (mean +/- SD, 26.00 +/- 7.62 nmol/L). Serum total T4 concentrations were inversely correlated with mortality. Differences in serum free T4 concentrations in sick cats (mean +/- SD, 27.70 +/- 13.53 pmol/L), compared with healthy cats (mean +/- SD, 24.79 +/- 8.33 pmol/L), were not significant. A few sick cats had serum free T4 concentrations greater than the reference range. Calculated free T4 fraction was significantly (P < 0.001) greater in sick cats (mean +/- SD, 0.24 +/- 0.30%), compared with healthy cats (mean +/- SD, 0.10 +/- 0.06%).

CLINICAL IMPLICATIONS:

Euthyroidism is maintained in sick cats, despite low serum total T4 concentrations. Measurement of serum total T4 concentrations is a valuable prognostic indicator. Serum free T4 concentrations should be used cautiously as a sole diagnostic criterion for confirmation of hyperthyroidism.

PMID:
8707673
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Loading ...
    Support Center