Plasma Leptin Concentrations in Cats: Reference Range, Effect of Weight Gain and Relationship with Adiposity as Measured by Dual Energy X-Ray Absorptiometry

Abstract

The aims of our study were to determine a reference range for plasma leptin in healthy, normal-weight cats and to measure the effect of weight gain on plasma leptin levels. To increase our understanding of the association between leptin and feline obesity, we investigated the relationship between plasma leptin and measures of adiposity in cats. Twenty-six normal-weight cats were used to determine the reference range for feline leptin using a multispecies radioimmunoassay. In the second part of the study, plasma leptin concentrations were determined in 16 cats before and after approximately 10 months of spontaneous weight gain. Dual energy X-ray absorptiometry scans (DEXA) were performed after weight gain. The tolerance interval for plasma leptin concentrations was 0.92-11.9 ng/ml Human Equivalent (HE) with a mean concentration of 6.41+/-2.19 ng/ml HE. In part two of the study, 16 cats gained on average 44.2% bodyweight over 10 months. The percentage of body fat in obese cats ranged from 34.2 to 48.7%. Mean plasma leptin concentrations increased from 7.88+/-4.02 ng/ml HE before weight gain to 24.5+/-12.1 ng/ml HE after weight gain, (P<0.001). Total body fat and body fat per cent were the strongest predictors of plasma leptin in obese cats (r=0.8 and r=0.78, P<0.001, respectively). In conclusion, plasma leptin concentrations increased three-fold in cats as a result of weight gain and were strongly correlated with the amount of adipose tissue present. Despite elevated leptin levels, cats continued to eat and gain weight, suggesting decreased sensitivity to leptin. This investigation into the biology of leptin in cats may aid the overall understanding of the role of leptin and the development of future treatments to help prevent and manage feline obesity.

Ovariohysterectomy alters body composition and adipose and skeletal muscle gene expression in cats fed a high-protein or moderate-protein diet

“…Leptin concentrations are positively correlated with adipose tissue mass (Appleton et al, 2000;Backus et al, 2000;Belsito et al, 2009). Backus et al (2000) used linear regression and estimated that for every 1 g increase in BW, a 1.2 ng/ml increase in leptin occurred.…”

“…Cats, similar to other species, have increased circulating leptin concentrations following weight gain. Increased blood leptin concentrations, without decreases in food intake suggests decreased leptin sensitivity (Appleton et al, 2000;Backus et al, 2000;Martin et al, 2001).…”

Inverse regulation of leptin mRNA expression by short- and long-chain fatty acids in cultured bovine adipocytes

“…Plasma concentrations of leptin are positively correlated with body fat content in various mammalian species including ruminants [3][4][5][6][7][8][9][10][11]. Therefore, circulating leptin is a suitable marker for adiposity in livestock animals and pets, and for assessment of long-term nutritional condition in wild animals.…”

Feline Leptin: Immunogenic and Biological Activities of the Recombinant Protein, and Its Measurement by ELISA

“…As in human, rodents and dogs [5,11,16], the blood leptin concentration in cats determined by commercially available radioimmuno assay (RIA) kit with anti-human leptin antibody and human leptin as a standard was shown to positively correlate with body fat content and to be higher in obesity [1,2]. These results suggest that blood leptin can be a quantitative marker of adiposity and obesity in cats, but validation of the feline leptin determination in blood is uncertain.…”

“…The body condition score using a diagram of silhouettes is one of the diagnostic scales of obesity in cats [21], but this is a somewhat subjective estimate. Alternatively, dual energy X-ray absorptiometry and deuterium oxide dilution method are useful for quantitative estimation of body fat mass in cats [1][2][3]15], but this is not easy for routine use.…”