Astrocytes possess steroid receptors as well as several enzymes typical of steroid target cells, such as 5 alpha-reductase, which converts testosterone (T) and progesterone (P) into their respective 5 alpha-reduced metabolites, and the 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD). Because of this, it was deemed of interest to analyze whether the original hormones P and T, and their 5 alpha-reduced metabolites dihydrotestosterone (DHT), 5 alpha-androstan-3 alpha,17 beta-diol (3 alpha-diol), dihydroprogesterone (DHP) and 5 alpha-pregnan-3 alpha-ol-2O-one (THP), might exert some effects on the expression of the most typical astrocytic market, i.e. the glial fibrillary acidic protein (GFAP). Cultures of rat type I astrocytes were exposed to the various steroids for 3, 6, and 24 h, and the variations of GFAP mRNA were measured by Northern blot analysis. A significant elevation of GFAP mRNA levels was observed after exposure to either P or DHP; the effect of DHP appeared more promptly (at 2 h) than that of P (at 6 h). This result suggests that the effect of P might be linked to its conversion into DHP; this hypothesis has been confirmed by showing that the addition of finasteride (a specific blocker of the 5 alpha-reductase) is able to completely abolish the effect of P. After exposure to DHP or THP, a decrease of GFAP gene expression was observed at later intervals (24 h). In the case of androgens, T and 3 alpha-diol did not change GFAP expression at any time of exposure, while DHT produced a significant decrease of GFAP mRNA only after 24 h of exposure. Taken together, the data indicate that the 5 alpha-reduced metabolites of P and T may modulate the expression of GFAP in type 1 rat astrocytes.

Effect of progesterone, testosterone and their 5 alpha-reduced metabolites on GFAP gene expression in type 1 astrocytes / R.C. Melcangi, M. Riva, F. Fumagalli, V. Magnaghi, G. Racagni, L. Martini. - In: BRAIN RESEARCH. - ISSN 0006-8993. - 711:1-2(1996), pp. 10-15.

Effect of progesterone, testosterone and their 5 alpha-reduced metabolites on GFAP gene expression in type 1 astrocytes

R.C. Melcangi
Primo
;
M. Riva
Secondo
;
F. Fumagalli;V. Magnaghi;G. Racagni
Penultimo
;
L. Martini
Ultimo
1996

Abstract

Astrocytes possess steroid receptors as well as several enzymes typical of steroid target cells, such as 5 alpha-reductase, which converts testosterone (T) and progesterone (P) into their respective 5 alpha-reduced metabolites, and the 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD). Because of this, it was deemed of interest to analyze whether the original hormones P and T, and their 5 alpha-reduced metabolites dihydrotestosterone (DHT), 5 alpha-androstan-3 alpha,17 beta-diol (3 alpha-diol), dihydroprogesterone (DHP) and 5 alpha-pregnan-3 alpha-ol-2O-one (THP), might exert some effects on the expression of the most typical astrocytic market, i.e. the glial fibrillary acidic protein (GFAP). Cultures of rat type I astrocytes were exposed to the various steroids for 3, 6, and 24 h, and the variations of GFAP mRNA were measured by Northern blot analysis. A significant elevation of GFAP mRNA levels was observed after exposure to either P or DHP; the effect of DHP appeared more promptly (at 2 h) than that of P (at 6 h). This result suggests that the effect of P might be linked to its conversion into DHP; this hypothesis has been confirmed by showing that the addition of finasteride (a specific blocker of the 5 alpha-reductase) is able to completely abolish the effect of P. After exposure to DHP or THP, a decrease of GFAP gene expression was observed at later intervals (24 h). In the case of androgens, T and 3 alpha-diol did not change GFAP expression at any time of exposure, while DHT produced a significant decrease of GFAP mRNA only after 24 h of exposure. Taken together, the data indicate that the 5 alpha-reduced metabolites of P and T may modulate the expression of GFAP in type 1 rat astrocytes.
Androgen ; Progestagen ; 5α-Reductase ; Glial fibrillary acidic protein ; Astrocyte ; Rat ; Central nervous system
Settore BIO/14 - Farmacologia
Settore MED/13 - Endocrinologia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/181710
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