title: Neuronal differentiation of PC12 cells abolishes the expression of membrane androgen receptors.
abstract: Sex steroids affect adrenal chromaffin cell function. In the present work, we have examined the expression and functional significance of membrane androgen receptor sites in normal rat adrenal chromaffin cells and in the PC12 rat pheochromocytoma cell line which can differentiate to either a neuronal or to an epithelial phenotype and expresses membrane estrogen receptor sites. Our data are as follows: (a) no cytosolic androgen receptors were found in both normal chromaffin and PC12 cells; (b) both types of chromaffin cells expressed high affinity membrane testosterone binding sites; (c) activation of these sites increased cytosolic Ca(2+), decreased catecholamine secretion and induced apoptosis; (d) NGF-induced neuronal differentiation of PC12 cells resulted in the suppression of the number of membrane testosterone sites. In conclusion, our data provide evidence for the existence of specific membrane testosterone receptors on adrenal chromaffin cells via which androgens, (some of them originating in the cortex) modulate their function. Neuronal differentiation of chromaffin cells results in a significant attenuation of these effects, via suppression of the expression of membrane androgen receptors suggesting, that the latter are specific for epithelioid chromaffin cells.
authors.affiliation: Laboratories of Experimental Endocrinology, University of Crete, School of Medicine, P.O. Box 2208, Heraklion 71003, Greece.
authors.forename: Vassilia-Ismini
authors.initials: VI
authors.lastname: Alexaki
authors.forename: Eirini
authors.initials: E
authors.lastname: Dermitzaki
authors.forename: Ioannis
authors.initials: I
authors.lastname: Charalampopoulos
authors.forename: Marilena
authors.initials: M
authors.lastname: Kampa
authors.forename: Artemissia-Phoebe
authors.initials: AP
authors.lastname: Nifli
authors.forename: Achille
authors.initials: A
authors.lastname: Gravanis
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Margioris
authors.forename: Elias
authors.initials: E
authors.lastname: Castanas
mesh_terms: D000313:Adrenal Medulla / Q000166:cytology / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002395:Catecholamines / Q000096:biosynthesis; D002454:Cell Differentiation; D019439:Chromaffin Cells / Q000166:cytology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005434:Flow Cytometry; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism*; D018613:Microscopy, Confocal; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D011944:Receptors, Androgen / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors
chemical_list: D002395:Catecholamines; D008565:Membrane Proteins; D011944:Receptors, Androgen; D013739:Testosterone; D002118:Calcium