Untitled

Abstract

Obesity occurs in the congenic LA/Ntul//-cp rat as the result of the autosomal epigenetic expression of the corpulent trait for obesity (the -cp trait) in association with hyperphagia, a decreased capacity for nonshivering thermogenesis, and develops differentially in subcutaneous and abdominal fat pad depots by processes of hyperplasia and hypertrophy of adipocytes at 6 weeks of age, and before the onset of overt obesity has developed. Once formed, differentiated adipocytes can remain active as lipid storage depots virtually indefinitely, to accommodate the energy needs of the organism as needed during both energy privation and excess. In contrast, preobese indices of linear growth were similar in both phenotypes.