Testosterone signaling through internalizable surface receptors in androgen receptor-free macrophages.
Testosterone acts on cells through intracellular transcription-regulating androgen receptors (ARs). Here, we show that mouse IC-21 macrophages lack the classical AR yet exhibit specific nongenomic responses to testosterone. These manifest themselves as testosterone-induced rapid increase in intracellular free [Ca(2+)], which is due to release of Ca(2+) from intracellular Ca(2+) stores. This Ca(2+) mobilization is also inducible by plasma membrane-impermeable testosterone-BSA. It is not affected by the AR blockers cyproterone and flutamide, whereas it is completely inhibited by the phospholipase C inhibitor U-73122 and pertussis toxin. Binding sites for testosterone are detectable on the surface of intact IC-21 cells, which become selectively internalized independent on caveolae and clathrin-coated vesicles upon agonist stimulation. Internalization is dependent on temperature, ATP, cytoskeletal elements, phospholipase C, and G-proteins. Collectively, our data provide evidence for the existence of G-protein-coupled, agonist-sequestrable receptors for testosterone in plasma membranes, which initiate a transcription-independent signaling pathway of testosterone.
Benten
W P
WP
Division of Molecular Parasitology and Centre of Biological-Medical Research, Heinrich-Heine-University, 40225 Duesseldorf, Germany.
Lieberherr
M
M
Stamm
O
O
Wrehlke
C
C
Guo
Z
Z
Wunderlich
F
F
D000726:Androgen Antagonists / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D003534:Cyproterone / Q000494:pharmacology; D004705:Endocytosis; D004958:Estradiol / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005434:Flow Cytometry; D005485:Flutamide / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects*; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D037342:Pertussis Toxin; D011760:Pyrrolidinones / Q000494:pharmacology; D011944:Receptors, Androgen / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D013739:Testosterone / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000726:Androgen Antagonists; D004963:Estrenes; D011760:Pyrrolidinones; D011944:Receptors, Androgen; D011956:Receptors, Cell Surface; D010566:Virulence Factors, Bordetella; C045037:testosterone-3-carboxymethyloxime-bovine serum albumin conjugate; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D012710:Serum Albumin, Bovine; D013739:Testosterone; D004958:Estradiol; D005485:Flutamide; D003534:Cyproterone; D037342:Pertussis Toxin; D010738:Type C Phospholipases; D002118:Calcium