Endocrine Abstracts

JOINT390

Comparative models of spontaneous endocrinopathies are powerful tools to understand disease etiology. The study of endocrine diseases in companion animals is particularly useful, as these animals share their environment with humans, and typically display clinical signs that phenocopy human symptoms. One such disease in domestic cats, hypersomatotropism (HST, feline acromegaly), is a disorder of excessive growth hormone and increased IGF-1 (Insulin like Growth Factor 1). Feline acromegaly is usually caused by hyperplasia or neuroendocrine tumors of the pars distalis of the pituitary gland. In this retrospective study, we used serum IGF-1 results to investigate population characteristics for domestic cats with HST in the United States and Canada. Laboratory records from 1Jan06 to 31Dec22 were reviewed and animals with a circulating IGF-1 hormone concentration of 190 nmol/l(1,450 ng/ml) or greater were presumed to have acromegaly. This review identified 4,620 such cats with a mean age (n = 4,351) of 11.2 years (median: 11.2, range: .5-20.3yr) and mean weight (n = 2,086) of 6.03 Kg (median: 5.91, range: 2.27-15.0 Kg). Males outnumbered females in the database, which included 3,048 males and 1,181 females. Domestic Short/Medium/Longhair cats were the most prevalent breed (n= 3,563; 77%), followed by Maine Coon cats (n = 120; 2.6%) and Siamese cats (n = 111, 2.4%). Just under half of the animals (n = 2,037, 44%) had a history of diabetes mellitus on the submission form. Most submissions were from the US (n = 4,347, 94%) with the largest number of affected cats being submitted from California (n = 841, 18.2%), New York (n = 604, 13.1%), Massachusetts (n = 402, 8.7%), Colorado (225, 4.9%), and Texas (200, 4.3%). The mean serum IGF-1 concentration of these animals was 358 nmol/ml (median: 345, range 190-761 nmol/ml). For comparison, an age and sex matched control group of 95 animals with residual samples previously submitted for unrelated testing was selected. The mean IGF-1 concentration for the control group was 97 nmol/ml (median: 85, range 0-311 nmol/ml). Therse data suggest that feline acromegaly is diagnosed most frequently in older male cats in North America, residing in areas that are likely to be more urbanized and subject to environmental pollutant exposure. Furthermore, some breed disposition is evident, suggesting a genetic component to the disease etiology in cats. Given that the prevalence of this disease in cats is potentially 10 times that seen in humans, we suggest that feline HST represents an excellent comparative model of acromegaly that warrants further investigation.