Insulin sensitivity and β-cell function in healthy cats:: Assessment with the use of the hyperglycemic glucose clamp

A hyperglycemic clamp (HGC) was developed for use in conscious cats. In 21 healthy, normal glucose tolerant cats glucose disposal rate (M), insulin sensitivity (ISIHGC), and beta-cell response (I) at arterial plasma glucose of 9 mmol . l(-1) were measured. The HGC was tolerated well and steady state glucose infusion was achieved. Compared to values reported for humans, M values for the cats were low, which appeared to relate to both a low ISIHGC and a low I. HGC measures correlated with fasting plasma glucose and insulin concentrations as well as with their HOMA (homeostasis model assessment) and QUICKI (quantitative insulin sensitivity check index) counterparts. Also, I and ISIHGC correlated with their counterparts derived from intravenous glucose tolerance tests. In conclusion, this is the first report of hyperglycemic glucose clamping in cats. The procedure (HGC) allows for measurements of glucose disposal, beta-cell response and insulin sensitivity. Compared to human data, both insulin sensitivity and insulin secretion appeared to be low in cats. This is compatible with the carnivorous nature of this species, for which insulin resistance would be advantageous during periods of restricted food availability.