Peer-reviewed veterinary case report
How radioactive iodine treatment affects IGF-1 levels in cats
By Shin, Dongheon et al.·Published in Journal of Feline Medicine and Surgery·2025·Laboratory of Veterinary Internal Medicine, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, South Korea, South Korea·View original on Crossref →
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Original publication title: Change in insulin-like growth factor type 1 concentration after radioactive iodine treatment in cats with hyperthyroidism
- Species:
- cat
Plain-English summary
A group of 13 cats with hyperthyroidism underwent radioactive iodine treatment to manage their condition. Before treatment, their thyroid hormone levels were high, but after six months, these levels dropped significantly, indicating successful treatment. Interestingly, the cats' insulin-like growth factor 1 (IGF-1) levels increased after treatment, suggesting an improvement in their overall health and metabolism. However, their kidney function showed some decline, as indicated by increased creatinine levels. Overall, the treatment helped lower thyroid hormone levels and improve the cats' health status.
People also search for: cat hyperthyroidism treatment · radioactive iodine for cats · cat kidney health after treatment
Abstract
Objectives This study aimed to evaluate changes in serum insulin-like growth factor type 1 (IGF-1) concentrations in cats with hyperthyroidism before and after radioactive iodine (RAI) treatment, as well as investigate the correlation between thyroid volume and serum IGF-1 concentrations. Methods A total of 13 cats with hyperthyroidism and 14 healthy controls were included. Serum total thyroxine (TT4)/thyroid-stimulating hormone (TSH) and IGF-1/insulin-like growth factor binding protein-3 (IGFBP-3) concentrations were measured using chemiluminescence immunoassay and ELISA, respectively, at presentation and 6 months after RAI treatment. The results were compared with thyroid volume measured using scintigraphy. Data are presented as median (interquartile range [IQR]) and analysed using non-parametric tests. Results Serum TT4 concentrations significantly decreased from 9.30 µg/dl (IQR 6.49–12.7) to 2.23 µg/dl (IQR 1.34–2.94) after RAI treatment ( P <0.001), while TSH levels increased from 0.021 ng/ml (IQR 0.021–0.021) to 0.125 ng/ml (IQR 0.050–0.257) ( P = 0.002). IGF-1 levels significantly increased from 329 ng/ml (IQR 240–479) to 572 ng/ml (IQR 402–1038) after RAI treatment ( P = 0.011), while IGFBP-3 levels did not differ. Serum creatinine concentrations significantly increased from 1.3 mg/dl (IQR 1.2–1.6) to 2.0 mg/dl (IQR 1.7–2.3) after RAI treatment ( P = 0.006). No correlation was observed between IGF-1 and any variable, except IGFBP-3 ( r s = 0.587; P = 0.039) in the pretreatment group. IGF-1 and body weight were significantly positively correlated after RAI treatment ( r s = 0.696; P = 0.011) but not before. In healthy cats, IGF-1 was negatively correlated with serum TT4 ( r s = –0.627; P = 0.019). Conclusions and relevance The increased serum IGF-1 concentrations after RAI treatment may reflect the restoration of anabolic status in cats with hyperthyroidism. In this study population, no correlation was found between thyroid volume and serum IGF-1 concentrations.
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Search related cases →Original publication on Crossref: https://doi.org/10.1177/1098612x251395870