THE GLUTAMATE-RECEPTOR SUBUNIT GLUR-I IS EXPRESSED IN GONADOTROPHS OFTHE ANTERIOR-PITUITARY AND IS REGULATED BY GONADAL FEEDBACK

An antiserum raised against a synthetic peptide corresponding to the C -terminal amino acid sequence (880-907) of the cloned glutamate recept or protein GluRl stained gonadotrophic cells in the adenohypophysis of normal male rats. The staining intensity was greatly increased in the hypertrophic gonadotrophs of long-term castrated rats. These results indicate that glutamate may act directly on pituitary gonadotrophs as a neuroendocrine modulator. Furthermore, the expression of GluRl in go nadotrophs (and thus these cells' ability to respond to glutamate) may be regulated by gonadal factors.