Open AccessEffect of Thyroxine Supplementation on Glomerular Filtration Rate in Hypothyroid Dogs
Author(s) -
Gommeren K.,
Van Hoek I.,
Lefebvre H.P.,
Benchekroun G.,
Smets P.,
Daminet S.
Publication year - 2009
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.1939-1676.2009.0331.x
Subject(s) - medicine , euthyroid , levothyroxine , renal function , endocrinology , urinalysis , creatinine , thyroid function , urology , hormone , urine
Background: Glomerular filtration rate (GFR) is decreased in humans with hypothyroidism, but information about kidney function in dogs with hypothyroidism is lacking. Hypothesis: Hypothyroidism influences GFR in dogs. The objective of this study was to assess GFR in hypothyroid dogs before implementation of thyroxine supplementation and after re‐establishing euthyroidism. Animals: Fourteen hypothyroid dogs without abnormalities on renal ultrasound examination or urinalysis. Methods: Blood pressure and GFR (measured by exogenous creatinine clearance) were measured before treatment (T0, n = 14) and at 1 month (T1, n = 14) and at 6 months (T6, n = 11) after beginning levothyroxine supplementation therapy (20 μg/kg/d, PO). The response to therapy was monitored at T1 by measuring serum total thyroxine and thyroid stimulating hormone concentrations. If needed, levothyroxine dosage was adjusted and reassessed after 1 month. Statistical analysis was performed using a general linear model. Results are expressed as mean ± standard deviation. Results: At T0, the average age of dogs in the study group was 6.3 ± 1.4 years. Their average body weight decreased from 35 ± 18 kg at T0 to 27 ± 14 kg at T6 ( P < .05). All dogs remained normotensive throughout the study. GFR increased significantly with levothyroxine supplementation; the corresponding results were 1.6 ± 0.4 mL/min/kg at T0, 2.1 ± 0.4 at T1, and 2.0 ± 0.4 at T6 ( P < .01). Conclusion: GFR was <2 mL/min/kg in untreated hypothyroid dogs. Re‐establishment of a euthyroid state increased GFR significantly.