FOOD RESTRICTION DELAYS THE AGE-RELATED INCREASE IN GFAP MESSENGER-RNA IN RAT HYPOTHALAMUS

Astrogliosis with advancing age is correlated with increased expressio n of glial fibrillary acidic protein (GFAP). Hypothalamic GFAP mRNA pr evalence was determined in male F344 rats of different ages that were fed ad lib (AL) and compared with that of rats that were food-restrict ed (FR) to 60% of AL levels. Hypothalamic GFAP mRNA increased 3-ford a t 24 to 25 months in AL rats compared with 3 and 6 month groups. There were no differences in GFAP mRNA levels between AL and FR rats from 3 to 18 months. However, GFAP mRNA was significantly lower in FR than i n AL rats at 24 to 25 months; FR rats reached the level of GFAP mRNA i n 24 to 25 months AL rats by 33 months. Hypothalamic glutamine synthet ase mRNA also increased with age in both dietary groups but did not di ffer between dietary groups at any age. The observation that FR delays the increased expression of GFAP in the hypothalamus during aging len ds support to the hypothesis that upregulation of GFAP mRNA is a bioma rker of brain aging.