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Serum transthyretin concentration is decreased in dogs with nonthyroidal illness
Author(s) -
Piechotta Marion,
Raila Jens,
Rick Markus,
Beyerbach Martin,
Hoppen HansOtto
Publication year - 2012
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/j.1939-165x.2011.00394.x
Subject(s) - transthyretin , medicine , endocrinology , serum concentration , albumin
Background Hypothyroidism in dogs is often difficult to diagnose owing to nonspecific clinical signs and laboratory test results that can be mimicked by nonthyroidal illness ( NTI ). Thyroxine ( T 4) circulates in blood mainly bound to T 4‐binding globulin and, to a lesser degree, transthyretin ( TTR ) and albumin. The concentration of total T 4 depends on the concentrations of these binding proteins. Objectives We hypothesized that dogs with NTI and decreased serum total T 4 concentrations would have decreased serum TTR concentrations. The objective of the study was to measure and compare serum TTR concentrations in healthy dogs, in dogs with NTI and low serum T 4 concentrations, and in dogs with hypothyroidism. Methods Assignment of dogs to 3 groups was based on physical examination and serum concentrations of T4 and TSH (mean ± SD ): for healthy dogs ( n = 13), T 4 was 24.8 ± 3.6 nmol/L and TSH was 0.15 ± 0.08 μg/L; for dogs with NTI and low T 4 ( n = 20), T 4 was 3.2 ± 3.0 nmol/L and TSH was 0.18 ± 0.13 μg/L; and for hypothyroid dogs ( n = 19), T4 was 5.3 ± 4.3 nmol/L and TSH was 2.33 ± 1.90 μg/L). TTR concentrations in serum were determined semiquantitatively using western blot analysis. Results Serum TTR concentration (mean ± SD ) was decreased in the dogs with NTI (24.8 ± 7.9 mg/L) compared with that of hypothyroid dogs (41.1 ± 21.4 mg/L, P = .0035). Differences were not found between TTR concentrations in clinically healthy dogs (33.3 ± 10.1 mg/L) and hypothyroid dogs or dogs with NTI . Conclusions Serum TTR concentrations were significantly decreased in dogs with NTI and low T 4 compared with concentrations in hypothyroid dogs. Additional studies should be done to determine if TTR concentrations can discriminate between dogs with NTI and low T 4 and dogs with primary hypothyroidism.