Equine estrogens induce apolipoprotein E and glial fibrillary acidic protein in mixed glial cultures.
Rozovsky-I; Hoving-S; Anderson-CP; O'Callaghan-J; Finch-CE
Neurosci Lett 2002 May; 323(3):191-194
Premarin, which contains several equine estrogens, as well as estradiol (E2) as a minor component, is widely used for replacement therapy of estrogen deficits, but little is known of its direct actions on brain cells. In mixed glial cultures, apolipoprotein E (apoE) and glial fibrillary acidic protein (GFAP) are induced by estrogens. GFAP induction showed an inverted-U shape E2 dose response, with a maximum induction at 1 pM, whereas apoE mRNA induction was greatest at 100 pM. GFAP and ApoE mRNAs were induced by equine estrogens in the following order: E2=equilin>estrone>17 alpha-dihydroequilenin. However, the induction of apoE secretion by 17 alpha-dihydroequilenin was as effective as by the other estrogens. The greater response of apoE secretion than GFAP mRNA induction to 17 alpha-dihydroequilenin might be therapeutically important because of the glial scarring during brain lesions, in which GFAP induction has a major role in inhibiting neurite outgrowth, whereas apoE secretion supports neurite outgrowth.
Proteins; Brain-damage; Brain-disorders; In-vitro-studies; In-vivo-studies; Laboratory-animals; Animal-studies; Animals
Neurogerontology Division, Andrus Gerontology Center and Department of Biological Sciences, University of Southern California, 3715 McClintoch Avenue, Los Angeles, CA 90089-0191, USA