EXPRESSION OF 112-KDA ESTROGEN-RECEPTOR IN MOUSE-BRAIN CORTEX AND ITSAUTOREGULATION WITH AGE

The mouse brain cortex expresses ER whose size is larger than uterus a nd level changes with age and hormonal treatment, Western blot analysi s shows the presence of 66 kDa ER in uterus but 112 and 116 kDa ER in the brain, Whereas 116 kDa ER is phosphorylated and predominantly pres ent in nuclei, 112 kDa ER is unphosphorylated and present in both cyto sol as well as nuclei, Similar to uterus, the level of ER decreases dr astically in the brain cortex of old mice. Hormonal regulation of ER s hows age-specific pattern. Ovariectomy reduces the level of ER in adul t but increases it significantly in old. While testosterone does not a lter the level of ER in either age, estradiol decreases it considerabl y in old but shows no detectable difference in adult, Our results prov ide evidence for the expression of a novel form of ER in mouse brain c ortex and its regulation by sex steroid hormones in age-specific manne r. (C) 1997 Academic Press.