AGE-RELATED DIFFERENCES IN THE THERMOGENIC AND PONDERAL EFFECTS FOLLOWING THE ADMINISTRATION OF FRAGMENT PEPTIDES FROM THE RAT OB PROTEIN

The ob gene encodes a protein, which regulates satiety, metabolic rate and fat storage. The administration of a pool of five 20-amino-acid f ragment peptides derived from the carboxy-terminal region of the ob pr otein produced a statistically significant reduction in body weight ga in in adult rats, while rectal temperature showed a statistically sign ificant increase. Administration of the same pool of peptides to young rats did not produce changes in body weight gain, although a statisti cally significant transient increase in rectal temperature was observe d. These results envisage the possibility that small sequences of amin o acids derived from the ob protein may mimic the effects of the whole protein on temperature and ponderal regulation. Furthermore, data sug gest possible age-related differences in the response to leptin admini stration. (C) 1998 Elsevier Science B.V.