Objective—To examine whether obese cats, compared
with lean cats, have alterations in lipoprotein
metabolism that might lead to a decrease in glucose
metabolism and insulin secretion.
Animals—10 lean and 10 obese adults cats (5
neutered males and 5 neutered females each).
Procedure—Intravenous glucose tolerance tests with
measurements of serum glucose, insulin, and nonesterified
fatty acid (NEFA) concentrations were performed.
Lipoprotein fractions were examined in
serum by isopycnic density gradient ultracentrifugation.
Results—Obese cats had insulin resistance. Plasma
triglyceride and cholesterol concentrations were significantly
increased in obese cats, compared with
lean cats. Very low density lipoprotein (VLDL) concentrations
were increased in obese cats, compared
with lean cats; however, the composition of various
fractions remained unchanged between obese and
lean cats, indicating greater synthesis and catabolism
of VLDL in obese cats. Serum high density lipoprotein
(HDL) cholesterol concentrations were increased in
obese cats, compared with lean cats. Serum NEFA
concentrations were only significantly different
between obese and lean cats when separated by sex;
obese male cats had higher baseline serum NEFA
concentrations and greater NEFA suppression in
response to insulin, compared with lean male cats.
Conclusions and Clinical Relevance—Lipid metabolism
changes in obese cats, compared with lean cats.
The increase in VLDL turnover in obese cats might
contribute to insulin resistance of glucose metabolism,
whereas the increase in serum HDL cholesterol
concentration might reflect a protective effect against
atherosclerosis in obese cats. (Am J Vet Res 2003;64:299–303)