METABOLISM OF STEROIDS IN PURE CULTURES OF NEURONS AND GLIAL-CELLS - ROLE OF INTRACELLULAR SIGNALING

In the brain, the 5 alpha-reductase converting testosterone (T) is pre sent both in neurons and in glial cells, even if it prevails in neuron s; the 3 alpha-hydroxysteroid-dehydrogenase (3 alpha-HSD), the enzyme converting dihydrotestosterone (DHT) into 3 alpha-diol, is particularl y concentrated in type 1 astrocytes. In glial cells, since the 5 alpha -reductase is activated by a cAMP analogue, PKA seems to be involved i n the control of this enzyme, postulating that nervous inputs utilizin g cAMP as the second messenger might modify the activity of this enzym e in glial cells. Moreover, the results indicate that, in type 1 astro cytes, both the 5 alpha-reductase and the 3 alpha-HSD are stimulated b y the co-culture with neurons and by the addition of neuron-conditione d medium, suggesting that secretory products released by neurons might intervene in the control of glial cell function.