Jaillardon L., Burger M. and Siliart B.
HYPERTHYROIDISM is a common endocrine disorder in old cats (Edinboro and others 2004). Thyrotoxicosis induces an increased catabolism with reduced fat and muscle mass despite the increased appetite (Meeking 2005). Adipose tissue is considered as a hormonally active system (Radin and others 2009) and express leptin (Ahima and Flier 2000). Leptin reflects the amount of body fat mass and decreases with weight reduction in cats and catabolic activities due to β agonists effect of the thyroid hormones (Appleton and others 2000, Shibata and others 2003, Hoenig and others 2007, 2008, Lee and Fried 2009). In various species, some report showed no change in blood leptin (Oge and others 2005, Iglesias and Díez 2007), while others showed an increase of blood leptin or a decrease (Nakamura and others 2000, Zimmermann-Belsing and others 2003, Iglesias and Díez 2007, Mazaki-Tovi and others 2010). No studies to date have investigated the possible variation leptin levels in hyperthyroid cats. The authors therefore aimed to measure and document plasma leptin values in hyperthyroid cats before and after methimazole treatment.