PARENT SESSION
NEUROENDOCRINOLOGY AND BIOLOGY OF THE PITUITARY GONADOTROPINS
Laurel
7:30 AM-10:00 AM

(502) IDENTIFICATION OF GENES THAT ARE DIFFERENTIALLY EXPRESSED IN THE FEMALE RAT HYPOTHALAMUS DURING AGING UTILIZING mRNA DIFFERENTIAL DISPLAY AND HIGH DENSITY DNA GENE CHIP ANALYSIS.

Wade, Marlene¹, Brann, Darrell¹, ¹ Neurobiology Program, Institute of Molecular Medicine and Genetics, Augusta, Georgia

ABSTRACT- In the female rat reproductive system, irregular cyclicity is first observed during middle age, followed by a transition to acyclicity and eventual loss of reproductive function. The mechanisms of reproductive aging are poorly understood. To gain new insights into the loss of reproductive function, mRNA Differential Display and high density DNA gene chip microarrays were utilized to identify genes that are differentially expressed in the hypothalamus from young versus middle aged female rats. Differential display demonstrated that the mRNA for the delta subunit of the translation elongation factor protein-1 (EF 1-delta) was down regulated in middle age as compared to young female rats, which was confirmed with northern blot analysis. For a more high-throughput analysis we utilized DNA gene chip microarrays containing ~8900 genes, of which ~4.1% appeared to be up-regulated two-fold and greater and ~2.3% appeared to be down regulated two-fold and greater in hypothalamic RNA from young versus middle aged female rats. As observed in the differential display study, gene chip results indicated that EF 1-delta mRNA was down regulated in middle age, as well as the remaining EF-1 subunits: alpha, beta, and gamma. In addition to these genes involved in mRNA translational control, other genes of interest include genes involved in neurotransmission, neurosecretion, cell death, and aging. Through the use of differential display and DNA gene chip analysis, we have identified genes that are differentially expressed in the hypothalamus of young versus middle aged female rats. This information should prove valuable to many researchers in the area of reproductive aging as well as the neurobiology of aging as it could provide new leads and insights into future directions of study.

KEY WORDS: gene chip analysis, hypothalamus, aging, gene expression