Adiponectin is an adipokine that is specifically expressed in adipose tissues, directly sensitizes the body to insulin via specific receptors and its decreased plasma concentration is responsible for insulin resistance in obese humans. Diabetes is an important problem also in veterinary medicine, and feline diabetes is very similar to human type 2 diabetes, in which obesity is an important risk factor. In the present study, We obtained cDNA clones corresponding to feline adiponectin and adiponectin receptor 1 (AD-R1), whose nucleotide and deduced amino acid sequences were highly identical to those of other species, especially, the extra-cellular domain of feline AD-R1 was almost identical to that of human AD-R1. Adiponectin mRNA was exclusively detected in the adipose tissue, but AD-R1 was in all tissues tested in this study. Next, plasma samples were collected from 22 cats visiting veterinary practices. They were divided to 2 groups based on a five-point scale body condition score (BCS), such as normal group (BCS ranged from 2.5 through 3.5) and obese group (BCS ranged from 4.0 through 5.0). Plasma adiponectin in obese cats (7.2 ± 1.5 μg/ml) was significantly lower than that of normal cats (18.0 ± 3.2 μg/ml). These results suggest that adiponectin may be responsible for insulin function also in the cat, and it can be a target molecule for treatment of obesity and diabetes in cats.

Pancreatitis is a common exocrine pancreatic disease in dogs, and the pancreatic lipase immunoreactivity (PLI) test is used for diagnosis. Enzyme catalytic assay is thought to have low specificity, but a lipase activity assay with increased specificity has been developed in human clinical chemistry. We measured serum lipase activity of 65 client-owned dogs using the newly developed FUJI DRI-CHEM slide and compared the results with their PLI concentrations. The results showed a good correlation (r=0.91), and the normal and pancreatitis dogs identified based on the PLI values were correctly separated based on lipase activity. The present study suggests that FUJI DRI-CHEM lipase activity would be helpful for diagnosis of pacreatitis in dogs and, in particular, that it can be used as a patient-side assay and contributes to immediate treatment.

G protein-coupled receptor (GPR) 120 is an unsaturated fatty acid receptor, which is associated with various physiological functions. It is reported that the genetic variant of GPR120, p.Arg270His, is detected more in obese people, and this genetic variation functionally relates to obesity in humans. Obesity is a common nutritional disorder also in dogs, but the genetic factors have not ever been identified in dogs. In this study, we investigated the molecular structure of canine GPR120 and searched for candidate genetic variants which may relate to obesity in dogs. Canine GPR120 was highly homologous to those of other species, and seven transmembrane domains and two N-glycosylation sites were conserved. GPR120 mRNA was expressed in lung, jejunum, ileum, colon, hypothalamus, hippocampus, spinal cord, bone marrow, dermis and white adipose tissues in dogs, as those in mice and humans. Genetic variants of GPR120 were explored in client-owned 141 dogs, resulting in that 5 synonymous and 4 non-synonymous variants were found. The variant c.595C>A (p.Pro199Thr) was found in 40 dogs, and the gene frequency was significantly higher in dogs with higher body condition scores, i.e. 0.320 in BCS4-5 dogs, 0.175 in BCS3 dogs and 0.000 in BCS2 dogs. We conclude that c.595C>A (p.Pro199Thr) is a candidate variant relating to obesity, which may be helpful for nutritional management of dogs.

Monocyte chemoattractant protein-1 (MCP-1) is a member of the C-C family chemokines, which mobilizes monocytes from bone marrow to the site of inflammation. To evaluate the clinical utility of canine MCP-1 as a blood test item, we measured serum MCP-1 concentrations in normal and ill dogs. Reference interval of canine MCP-1 was established as 115.6–176.9 pg/ml. Serum MCP-1 concentrations increased in the dogs affected with neoplastic (518.0 ± 84.8 pg/ml), inflammatory (257.0 ± 42.5 pg/ml) or other diseases (360.3 ± 45.2 pg/ml). The results showed high sensitivity of MCP-1 to detect neoplasia and inflammation. Moreover, MCP-1 increased in some cases in which C-reactive protein didn’t increase. MCP-1 might be helpful as a screening blood test marker for detection of neoplasia and inflammation in dogs.

Nesfatin-1 is an anorexic peptide derived from a precursor, nucleobindin-2 (NUCB2), which is distributed in various organs, coexists with ghrelin in the gastric X/A-like cells and closely relates to an appetite control in rodents and humans. Nesfatin-1 may be a significant factor addressing the satiety also in veterinary medicine, however, there are few reports about nesfatin-1 in dogs. In the present study, we detected canine NUCB2/nesfatin-1 mRNA in various tissues, especially abundant in pancreas, gastrointestinal tracts, testis and cerebellum. We examined circulating nesfatin-1 concentrations and NUCB2/nesfatin-1 mRNA expressions in upper gastrointestinal tracts (gastric corpus, pyloric antrum and duodenum) in dogs fed on different types of diets. Plasma nesfatin-1 concentrations in the dogs were approximately 4 ng/ml and they did not change after feeding through the study, however, NUCB2/nesfatin-1 mRNA expressions in pyloric antrum were 1.84-fold higher in the dogs fed on a High fiber/High protein diet (P<0.001), 1.48-fold higher in the dogs fed on a High fat/Low protein diet (P<0.05) and 1.02-fold higher in the dogs fed on a Low fat/High carbohydrate diet (not significant) comparing to those on a control diet. It was concluded that High fiber/High protein and High fat/Low protein diets increased NUCB2/nesfatin-1 production in canine gastrointestinal tracts. These results may set the stage for further investigations of canine NUCB2/nesfatin-1, which may relate to satiety effects in dogs.