The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform

L. Martini - One of the best experts on this subject based on the ideXlab platform.

  • Testosterone and Progesterone Metabolism in the central nervous system: Cellular localization and mechanism of control of the enzymes involved
    Cellular and Molecular Neurobiology, 1996
    Co-Authors: L. Martini, F. Celotti, R. C. Melcangi
    Abstract:

    This paper summarizes the most recent data obtained in the authors' laboratory on the Metabolism of testosterone and Progesterone in neurons and in the glia. 1. The activities of 5 α -reductase (the enzyme that converts testosterone into dihydrotestosterone; DHT) and of 3 α -hydroxy steroid dehydrogenase (the enzyme that converts DHT into 5 α -androstane-3 α ,17 β -diol; 3 α -diol) were first evaluated in primary cultures of neurons, oligodendrocytes, and type-1 and type-2 astrocytes, obtained from the fetal or neonatal rat brain. The formation of DHT and 3 α -diol was evaluated incubating the different cultures with labeled testosterone or labeled DHT as substrates. The results obtained indicate that the formation of DHT takes place preferentially in neurons; however, also type-2 astrocytes and oligodendrocytes possess considerable 5 α -reductase activity. A completely different localization was observed for 3 α -hydroxysteroid dehydrogenase; the formation of 3 α -diol appears to be prevalently, if not exclusively, present in type-1 astrocytes; 3 α -diol is formed in very low yields by neurons, type-2 astrocytes, and oligodendrocytes. Moreover, the results indicate that, in type 1 astrocytes, both 5 α -reductase and 3 α -HSD are stimulated by coculture with neurons and by the addition of neuron-conditioned medium, suggesting that secretory products released by neurons might intervene in the control of glial cell function. 2. Subsequently it was shown that, similarly to what happens when testosterone is used as the substrate, 5 α -reductase, which metabolizes Progesterone into 5 α -pregnane-3,20-dione, (DHP), shows a significantly higher activity in neurons than in glial cells; however, also type-1 and type-2 astrocytes as well as oligodendrocytes possess some ability to 5 α -reduce Progesterone. On the contrary, 3 α -hydroxysteroid dehydrogenase, the enzyme which converts DHP into 5 α -pregnane-3 α -ol-20-one (THP), appears to be present mainly in type-1 astrocytes; much lower levels of this enzyme are present in neurons and in type-2 astrocytes. At variance with the previous results obtained using androgens as precursors, oligodendrocytes show considerable 3 α -hydroxysteroid dehydrogenase activity, even if this is statistically lower than that present in type-1 astrocytes. The existence of isoenzymatic forms of the enzymes involved in androgen and Progesterone Metabolism is discussed.

  • testosterone and Progesterone Metabolism in the human neuroblastoma cell line sh sy5y
    The Journal of Steroid Biochemistry and Molecular Biology, 1993
    Co-Authors: R. C. Melcangi, R. Maggi, L. Martini
    Abstract:

    Abstract The ability of the human neuroblastoma cell line SH-SY5Y to metabolize androgens and Progesterone was studied by incubating the cells in the presence of labeled testosterone (T) or Progesterone (P) to measure, respectively, the formation of dihydrotestosterone (DHT) or dihydroProgesterone (DHP) (5α-reductase activitiy). The 3α-hydroxysteroid dehydrogenase activity was studied by evaluating the conversion of labeled DHT into 5α-androstan-3α, 17β-diol (3α-diol). The results show that undifferentiated neuroblastoma cells posses a significant 5α-reductase activity, as shown by the considerable conversion of T into DHT; moreover, this enzymatic activity seems to be significantly stimulated following cell differentiation induced by the phorbol ester TPA, but not after differentiation induced by retinoic acid (RA). The 5α-reductase(s) present in SH-SY5Y cells is also able to convert P into DHP. In undifferentiated cells, this conversion was about 8 times higher than that of T into DHT. Under the influences of TPA and RA, the formation of DHP followed the same pattern observed for the formation of DHT. SH-SY5Y cells also appear to possess the enzyme 3α-hydroxysteroid dehydrogenase, since they are able to convert DHT into 3α-diol. This enzymatic activity is not altered following TPA-induced differentiation and appears to be decreased following treatment with RA. It is suggested that the SH-SY5Y cell line may represent a useful “ in vitro ” model for the study of the mechanisms involved in the control of androgen and P Metabolism in nervous cells.

  • Testosterone and Progesterone Metabolism in the human neuroblastoma cell line SH-SY5Y
    'Elsevier BV', 1993
    Co-Authors: R. C. Melcangi, R. Maggi, L. Martini
    Abstract:

    The ability of the human neuroblastoma cell line SH-SY5Y to metabolize androgens and Progesterone was studied by incubating the cells in the presence of labeled testosterone (T) or Progesterone (P) to measure, respectively, the formation of dihydrotestosterone (DHT) or dihydroProgesterone (DHP) (5 alpha-reductase activity). The 3 alpha-hydroxysteroid dehydrogenase activity was studied by evaluating the conversion of labeled DHT into 5 alpha-androstan-3 alpha, 17 beta-diol (3 alpha-diol). The results show that undifferentiated neuroblastoma cells possess a significant 5 alpha-reductase activity, as shown by the considerable conversion of T into DHT; moreover, this enzymatic activity seems to be significantly stimulated following cell differentiation induced by the phorbol ester TPA, but not after differentiation induced by retinoic acid (RA). The 5 alpha-reductase(s) present in SH-SY5Y cells is also able to convert P into DHP. In undifferentiated cells, this conversion was about 8 times higher than that of T into DHT. Under the influences of TPA and RA, the formation of DHP followed the same pattern observed for the formation of DHT. SH-SY5Y cells also appear to possess the enzyme 3 alpha-hydroxysteroid dehydrogenase, since they are able to convert DHT into 3 alpha-diol. This enzymatic activity is not altered following TPA-induced differentiation and appears to be decreased following treatment with RA. It is suggested that the SH-SY5Y cell line may represent a useful "in vitro" model for the study of the mechanisms involved in the control of androgen and P Metabolism in nervous cells

  • Androgen and Progesterone Metabolism in the central and peripheral nervous system.
    The Journal of steroid biochemistry and molecular biology, 1993
    Co-Authors: L. Martini, R. C. Melcangi, R. Maggi
    Abstract:

    This paper summarizes the most recent data obtained in the authors' laboratory on the Metabolism of testosterone and Progesterone in neurons, in the glia, and in neuroblastoma cells. The activities of the 5 alpha-reductase (the enzyme that converts testosterone into dihydrotestosterone, DHT), and of the 3 alpha-hydroxysteroid dehydrogenase (the enzyme that converts DHT into 5 alpha-androstane-3 alpha, 17 beta-diol, 3 alpha-diol) have been first evaluated in primary cultures of neurons, oligodendrocytes and type-1 and -2 astrocytes, obtained from the fetal or neonatal rat brain. All the cultures were used on the fifth day. The formation of DHT of 3 alpha-diol was evaluated incubating the different cultures with labeled testosterone or DHT as substrates. The results obtained indicate that the formation of DHT takes place preferentially in neurons; however, type-2 astrocytes and oligodendrocytes also possess considerable 5 alpha-reductase activity, while type-1 astrocytes show a much lower enzymatic concentration. A completely different localization was observed for 3 alpha-hydroxysteroid dehydrogenase; the formation of 3 alpha-diol appears to be prevalently, if not exclusively, present in type-1 astrocytes; 3 alpha-diol is formed in very low yields by neurons, type-2 astrocytes and oligodendrocytes. The compartmentalization of two strictly correlated enzymes (5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase) in separate central nervous system (CNS) cell populations suggests the simultaneous participation of neurons and glial cells in the 5 alpha-reductive Metabolism of testosterone. Subsequently it has been shown that, similarly to what happens when testosterone is used as the substrate, the 5 alpha-reductase which metabolizes Progesterone into 5 alpha-pregnane-3,20-dione (DHP) shows a significantly higher activity in neurons than in glial cells; however, type-1 and -2 astrocytes as well as oligodendrocytes also possess some ability to 5 alpha-reduce Progesterone. On the other hand, 3 alpha-hydroxysteroid dehydrogenase, the enzyme which converts DHP into 5 alpha-pregnane-3 alpha-ol-20-one, appears to be present mainly in type-1 astrocytes; much lower levels of this enzyme are present in neurons and in type-2 astrocytes. At variance with the previous results obtained using androgens as precursors, oligodendrocytes show considerable 3 alpha-hydroxysteroid dehydrogenase activity, even if this is statistically lower than that present in type-1 astrocytes. The existence of isoforms of the enzyme involved in androgen and Progesterone Metabolism is discussed.(ABSTRACT TRUNCATED AT 400 WORDS)

R. C. Melcangi - One of the best experts on this subject based on the ideXlab platform.

  • Testosterone and Progesterone Metabolism in the central nervous system: Cellular localization and mechanism of control of the enzymes involved
    Cellular and Molecular Neurobiology, 1996
    Co-Authors: L. Martini, F. Celotti, R. C. Melcangi
    Abstract:

    This paper summarizes the most recent data obtained in the authors' laboratory on the Metabolism of testosterone and Progesterone in neurons and in the glia. 1. The activities of 5 α -reductase (the enzyme that converts testosterone into dihydrotestosterone; DHT) and of 3 α -hydroxy steroid dehydrogenase (the enzyme that converts DHT into 5 α -androstane-3 α ,17 β -diol; 3 α -diol) were first evaluated in primary cultures of neurons, oligodendrocytes, and type-1 and type-2 astrocytes, obtained from the fetal or neonatal rat brain. The formation of DHT and 3 α -diol was evaluated incubating the different cultures with labeled testosterone or labeled DHT as substrates. The results obtained indicate that the formation of DHT takes place preferentially in neurons; however, also type-2 astrocytes and oligodendrocytes possess considerable 5 α -reductase activity. A completely different localization was observed for 3 α -hydroxysteroid dehydrogenase; the formation of 3 α -diol appears to be prevalently, if not exclusively, present in type-1 astrocytes; 3 α -diol is formed in very low yields by neurons, type-2 astrocytes, and oligodendrocytes. Moreover, the results indicate that, in type 1 astrocytes, both 5 α -reductase and 3 α -HSD are stimulated by coculture with neurons and by the addition of neuron-conditioned medium, suggesting that secretory products released by neurons might intervene in the control of glial cell function. 2. Subsequently it was shown that, similarly to what happens when testosterone is used as the substrate, 5 α -reductase, which metabolizes Progesterone into 5 α -pregnane-3,20-dione, (DHP), shows a significantly higher activity in neurons than in glial cells; however, also type-1 and type-2 astrocytes as well as oligodendrocytes possess some ability to 5 α -reduce Progesterone. On the contrary, 3 α -hydroxysteroid dehydrogenase, the enzyme which converts DHP into 5 α -pregnane-3 α -ol-20-one (THP), appears to be present mainly in type-1 astrocytes; much lower levels of this enzyme are present in neurons and in type-2 astrocytes. At variance with the previous results obtained using androgens as precursors, oligodendrocytes show considerable 3 α -hydroxysteroid dehydrogenase activity, even if this is statistically lower than that present in type-1 astrocytes. The existence of isoenzymatic forms of the enzymes involved in androgen and Progesterone Metabolism is discussed.

  • testosterone and Progesterone Metabolism in the human neuroblastoma cell line sh sy5y
    The Journal of Steroid Biochemistry and Molecular Biology, 1993
    Co-Authors: R. C. Melcangi, R. Maggi, L. Martini
    Abstract:

    Abstract The ability of the human neuroblastoma cell line SH-SY5Y to metabolize androgens and Progesterone was studied by incubating the cells in the presence of labeled testosterone (T) or Progesterone (P) to measure, respectively, the formation of dihydrotestosterone (DHT) or dihydroProgesterone (DHP) (5α-reductase activitiy). The 3α-hydroxysteroid dehydrogenase activity was studied by evaluating the conversion of labeled DHT into 5α-androstan-3α, 17β-diol (3α-diol). The results show that undifferentiated neuroblastoma cells posses a significant 5α-reductase activity, as shown by the considerable conversion of T into DHT; moreover, this enzymatic activity seems to be significantly stimulated following cell differentiation induced by the phorbol ester TPA, but not after differentiation induced by retinoic acid (RA). The 5α-reductase(s) present in SH-SY5Y cells is also able to convert P into DHP. In undifferentiated cells, this conversion was about 8 times higher than that of T into DHT. Under the influences of TPA and RA, the formation of DHP followed the same pattern observed for the formation of DHT. SH-SY5Y cells also appear to possess the enzyme 3α-hydroxysteroid dehydrogenase, since they are able to convert DHT into 3α-diol. This enzymatic activity is not altered following TPA-induced differentiation and appears to be decreased following treatment with RA. It is suggested that the SH-SY5Y cell line may represent a useful “ in vitro ” model for the study of the mechanisms involved in the control of androgen and P Metabolism in nervous cells.

  • Testosterone and Progesterone Metabolism in the human neuroblastoma cell line SH-SY5Y
    'Elsevier BV', 1993
    Co-Authors: R. C. Melcangi, R. Maggi, L. Martini
    Abstract:

    The ability of the human neuroblastoma cell line SH-SY5Y to metabolize androgens and Progesterone was studied by incubating the cells in the presence of labeled testosterone (T) or Progesterone (P) to measure, respectively, the formation of dihydrotestosterone (DHT) or dihydroProgesterone (DHP) (5 alpha-reductase activity). The 3 alpha-hydroxysteroid dehydrogenase activity was studied by evaluating the conversion of labeled DHT into 5 alpha-androstan-3 alpha, 17 beta-diol (3 alpha-diol). The results show that undifferentiated neuroblastoma cells possess a significant 5 alpha-reductase activity, as shown by the considerable conversion of T into DHT; moreover, this enzymatic activity seems to be significantly stimulated following cell differentiation induced by the phorbol ester TPA, but not after differentiation induced by retinoic acid (RA). The 5 alpha-reductase(s) present in SH-SY5Y cells is also able to convert P into DHP. In undifferentiated cells, this conversion was about 8 times higher than that of T into DHT. Under the influences of TPA and RA, the formation of DHP followed the same pattern observed for the formation of DHT. SH-SY5Y cells also appear to possess the enzyme 3 alpha-hydroxysteroid dehydrogenase, since they are able to convert DHT into 3 alpha-diol. This enzymatic activity is not altered following TPA-induced differentiation and appears to be decreased following treatment with RA. It is suggested that the SH-SY5Y cell line may represent a useful "in vitro" model for the study of the mechanisms involved in the control of androgen and P Metabolism in nervous cells

  • Androgen and Progesterone Metabolism in the central and peripheral nervous system.
    The Journal of steroid biochemistry and molecular biology, 1993
    Co-Authors: L. Martini, R. C. Melcangi, R. Maggi
    Abstract:

    This paper summarizes the most recent data obtained in the authors' laboratory on the Metabolism of testosterone and Progesterone in neurons, in the glia, and in neuroblastoma cells. The activities of the 5 alpha-reductase (the enzyme that converts testosterone into dihydrotestosterone, DHT), and of the 3 alpha-hydroxysteroid dehydrogenase (the enzyme that converts DHT into 5 alpha-androstane-3 alpha, 17 beta-diol, 3 alpha-diol) have been first evaluated in primary cultures of neurons, oligodendrocytes and type-1 and -2 astrocytes, obtained from the fetal or neonatal rat brain. All the cultures were used on the fifth day. The formation of DHT of 3 alpha-diol was evaluated incubating the different cultures with labeled testosterone or DHT as substrates. The results obtained indicate that the formation of DHT takes place preferentially in neurons; however, type-2 astrocytes and oligodendrocytes also possess considerable 5 alpha-reductase activity, while type-1 astrocytes show a much lower enzymatic concentration. A completely different localization was observed for 3 alpha-hydroxysteroid dehydrogenase; the formation of 3 alpha-diol appears to be prevalently, if not exclusively, present in type-1 astrocytes; 3 alpha-diol is formed in very low yields by neurons, type-2 astrocytes and oligodendrocytes. The compartmentalization of two strictly correlated enzymes (5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase) in separate central nervous system (CNS) cell populations suggests the simultaneous participation of neurons and glial cells in the 5 alpha-reductive Metabolism of testosterone. Subsequently it has been shown that, similarly to what happens when testosterone is used as the substrate, the 5 alpha-reductase which metabolizes Progesterone into 5 alpha-pregnane-3,20-dione (DHP) shows a significantly higher activity in neurons than in glial cells; however, type-1 and -2 astrocytes as well as oligodendrocytes also possess some ability to 5 alpha-reduce Progesterone. On the other hand, 3 alpha-hydroxysteroid dehydrogenase, the enzyme which converts DHP into 5 alpha-pregnane-3 alpha-ol-20-one, appears to be present mainly in type-1 astrocytes; much lower levels of this enzyme are present in neurons and in type-2 astrocytes. At variance with the previous results obtained using androgens as precursors, oligodendrocytes show considerable 3 alpha-hydroxysteroid dehydrogenase activity, even if this is statistically lower than that present in type-1 astrocytes. The existence of isoforms of the enzyme involved in androgen and Progesterone Metabolism is discussed.(ABSTRACT TRUNCATED AT 400 WORDS)

Cheryl A. Frye - One of the best experts on this subject based on the ideXlab platform.

  • seizure exacerbation associated with inhibition of Progesterone Metabolism
    Annals of Neurology, 2003
    Co-Authors: Andrew G. Herzog, Cheryl A. Frye
    Abstract:

    The reduced Progesterone metabolite tetrahydroProgesterone is a potent positive modulator of GABAA chloride conductance that exerts powerful neuroinhibitiory and antiseizure effects in animal models. Cyclic natural Progesterone use may lessen seizure frequency in women with catamenial seizure exacerbation. We report a case in which efficacy was eliminated during concomitant treatment with a reductase inhibitor. The observation suggests that a reduced metabolite, rather than Progesterone itself, was responsible for improved seizure control. Ann Neurol 2003;53:390–391

  • Seizure exacerbation associated with inhibition of Progesterone Metabolism.
    Annals of neurology, 2003
    Co-Authors: Andrew G. Herzog, Cheryl A. Frye
    Abstract:

    The reduced Progesterone metabolite tetrahydroProgesterone is a potent positive modulator of GABA(A) chloride conductance that exerts powerful neuroinhibitiory and anti-seizure effects in animal models. Cyclic natural Progesterone use may lessen seizure frequency in women with catamenial seizure exacerbation. We report a case in which efficacy was eliminated during concomitant treatment with a reductase inhibitor. The observation suggests that a reduced metabolite, rather than Progesterone itself, was responsible for improved seizure control.

Andrew G. Herzog - One of the best experts on this subject based on the ideXlab platform.

  • seizure exacerbation associated with inhibition of Progesterone Metabolism
    Annals of Neurology, 2003
    Co-Authors: Andrew G. Herzog, Cheryl A. Frye
    Abstract:

    The reduced Progesterone metabolite tetrahydroProgesterone is a potent positive modulator of GABAA chloride conductance that exerts powerful neuroinhibitiory and antiseizure effects in animal models. Cyclic natural Progesterone use may lessen seizure frequency in women with catamenial seizure exacerbation. We report a case in which efficacy was eliminated during concomitant treatment with a reductase inhibitor. The observation suggests that a reduced metabolite, rather than Progesterone itself, was responsible for improved seizure control. Ann Neurol 2003;53:390–391

  • Seizure exacerbation associated with inhibition of Progesterone Metabolism.
    Annals of neurology, 2003
    Co-Authors: Andrew G. Herzog, Cheryl A. Frye
    Abstract:

    The reduced Progesterone metabolite tetrahydroProgesterone is a potent positive modulator of GABA(A) chloride conductance that exerts powerful neuroinhibitiory and anti-seizure effects in animal models. Cyclic natural Progesterone use may lessen seizure frequency in women with catamenial seizure exacerbation. We report a case in which efficacy was eliminated during concomitant treatment with a reductase inhibitor. The observation suggests that a reduced metabolite, rather than Progesterone itself, was responsible for improved seizure control.

R. Maggi - One of the best experts on this subject based on the ideXlab platform.

  • testosterone and Progesterone Metabolism in the human neuroblastoma cell line sh sy5y
    The Journal of Steroid Biochemistry and Molecular Biology, 1993
    Co-Authors: R. C. Melcangi, R. Maggi, L. Martini
    Abstract:

    Abstract The ability of the human neuroblastoma cell line SH-SY5Y to metabolize androgens and Progesterone was studied by incubating the cells in the presence of labeled testosterone (T) or Progesterone (P) to measure, respectively, the formation of dihydrotestosterone (DHT) or dihydroProgesterone (DHP) (5α-reductase activitiy). The 3α-hydroxysteroid dehydrogenase activity was studied by evaluating the conversion of labeled DHT into 5α-androstan-3α, 17β-diol (3α-diol). The results show that undifferentiated neuroblastoma cells posses a significant 5α-reductase activity, as shown by the considerable conversion of T into DHT; moreover, this enzymatic activity seems to be significantly stimulated following cell differentiation induced by the phorbol ester TPA, but not after differentiation induced by retinoic acid (RA). The 5α-reductase(s) present in SH-SY5Y cells is also able to convert P into DHP. In undifferentiated cells, this conversion was about 8 times higher than that of T into DHT. Under the influences of TPA and RA, the formation of DHP followed the same pattern observed for the formation of DHT. SH-SY5Y cells also appear to possess the enzyme 3α-hydroxysteroid dehydrogenase, since they are able to convert DHT into 3α-diol. This enzymatic activity is not altered following TPA-induced differentiation and appears to be decreased following treatment with RA. It is suggested that the SH-SY5Y cell line may represent a useful “ in vitro ” model for the study of the mechanisms involved in the control of androgen and P Metabolism in nervous cells.

  • Testosterone and Progesterone Metabolism in the human neuroblastoma cell line SH-SY5Y
    'Elsevier BV', 1993
    Co-Authors: R. C. Melcangi, R. Maggi, L. Martini
    Abstract:

    The ability of the human neuroblastoma cell line SH-SY5Y to metabolize androgens and Progesterone was studied by incubating the cells in the presence of labeled testosterone (T) or Progesterone (P) to measure, respectively, the formation of dihydrotestosterone (DHT) or dihydroProgesterone (DHP) (5 alpha-reductase activity). The 3 alpha-hydroxysteroid dehydrogenase activity was studied by evaluating the conversion of labeled DHT into 5 alpha-androstan-3 alpha, 17 beta-diol (3 alpha-diol). The results show that undifferentiated neuroblastoma cells possess a significant 5 alpha-reductase activity, as shown by the considerable conversion of T into DHT; moreover, this enzymatic activity seems to be significantly stimulated following cell differentiation induced by the phorbol ester TPA, but not after differentiation induced by retinoic acid (RA). The 5 alpha-reductase(s) present in SH-SY5Y cells is also able to convert P into DHP. In undifferentiated cells, this conversion was about 8 times higher than that of T into DHT. Under the influences of TPA and RA, the formation of DHP followed the same pattern observed for the formation of DHT. SH-SY5Y cells also appear to possess the enzyme 3 alpha-hydroxysteroid dehydrogenase, since they are able to convert DHT into 3 alpha-diol. This enzymatic activity is not altered following TPA-induced differentiation and appears to be decreased following treatment with RA. It is suggested that the SH-SY5Y cell line may represent a useful "in vitro" model for the study of the mechanisms involved in the control of androgen and P Metabolism in nervous cells

  • Androgen and Progesterone Metabolism in the central and peripheral nervous system.
    The Journal of steroid biochemistry and molecular biology, 1993
    Co-Authors: L. Martini, R. C. Melcangi, R. Maggi
    Abstract:

    This paper summarizes the most recent data obtained in the authors' laboratory on the Metabolism of testosterone and Progesterone in neurons, in the glia, and in neuroblastoma cells. The activities of the 5 alpha-reductase (the enzyme that converts testosterone into dihydrotestosterone, DHT), and of the 3 alpha-hydroxysteroid dehydrogenase (the enzyme that converts DHT into 5 alpha-androstane-3 alpha, 17 beta-diol, 3 alpha-diol) have been first evaluated in primary cultures of neurons, oligodendrocytes and type-1 and -2 astrocytes, obtained from the fetal or neonatal rat brain. All the cultures were used on the fifth day. The formation of DHT of 3 alpha-diol was evaluated incubating the different cultures with labeled testosterone or DHT as substrates. The results obtained indicate that the formation of DHT takes place preferentially in neurons; however, type-2 astrocytes and oligodendrocytes also possess considerable 5 alpha-reductase activity, while type-1 astrocytes show a much lower enzymatic concentration. A completely different localization was observed for 3 alpha-hydroxysteroid dehydrogenase; the formation of 3 alpha-diol appears to be prevalently, if not exclusively, present in type-1 astrocytes; 3 alpha-diol is formed in very low yields by neurons, type-2 astrocytes and oligodendrocytes. The compartmentalization of two strictly correlated enzymes (5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase) in separate central nervous system (CNS) cell populations suggests the simultaneous participation of neurons and glial cells in the 5 alpha-reductive Metabolism of testosterone. Subsequently it has been shown that, similarly to what happens when testosterone is used as the substrate, the 5 alpha-reductase which metabolizes Progesterone into 5 alpha-pregnane-3,20-dione (DHP) shows a significantly higher activity in neurons than in glial cells; however, type-1 and -2 astrocytes as well as oligodendrocytes also possess some ability to 5 alpha-reduce Progesterone. On the other hand, 3 alpha-hydroxysteroid dehydrogenase, the enzyme which converts DHP into 5 alpha-pregnane-3 alpha-ol-20-one, appears to be present mainly in type-1 astrocytes; much lower levels of this enzyme are present in neurons and in type-2 astrocytes. At variance with the previous results obtained using androgens as precursors, oligodendrocytes show considerable 3 alpha-hydroxysteroid dehydrogenase activity, even if this is statistically lower than that present in type-1 astrocytes. The existence of isoforms of the enzyme involved in androgen and Progesterone Metabolism is discussed.(ABSTRACT TRUNCATED AT 400 WORDS)