IEPA.d162.s390
We previously reported that adiposity and serum leptin levels increase with age in male F-344xBN rats and that when physiological levels of serum leptin are manipulated by fasting, there is a corresponding reciprocal change in hypothalamic neuropeptide Y (NPY) mRNA in young rats, but there are no changes in older rats
IEPA.d162.s391
These findings suggest that the regulation of hypothalamic NPY mRNA by leptin may be impaired with age
IEPA.d162.s392
We examined daily food consumption, body weight, whole-body oxygen consumption, serum leptin, and NPY mRNA in the hypothalamus
IEPA.d162.s393
Leptin infusion diminished hypothalamic NPY levels by nearly 50% compared with pair-fed young rats, whereas there were no changes in the hypothalamic NPY mRNA levels in senescent rats
IEPA.d162.s394
These diminished responses to leptin were associated with and may be the result of an impaired suppression of hypothalamic NPY mRNA levels