Endocrine Abstracts

Introduction: Limited data, support the notion that testosterone induces oxidative stress. Corticotropin-releasing hormone (CRH) participates locally in the endothelial inflammatory response by regulating the pro-oxidative mechanisms of the endothelium, inducing its adaptation to local stress. The present study was undertaken to determine whether the CRH induced pro-oxidant activity in macroendothelial cells under basal conditions, is regulated In vitro by androgen (testosterone-DHT).

Materials and methods: EA.hy926 endothelial cells were cultured in DMEM phenol red free without FBS for 24 hours. Growth medium was replaced and then CRH (10^–7 M), and CRH plus testosterone (0.5nM) or DHT (0.5nM) alone or in combination with the androgen receptor antagonist flutamide (50nM), were added to the culture media and cells incubated for 2 more hours. Intracellular reactive oxygen species (ROS) content, endothelial nitric oxide synthase (eNOS) activity, nitric oxide (NO) levels, superoxide dismutase (SOD) activity, catalase activity (CAT), and glutathione (GSH) levels were measured.

Results: Testosterone and DHT abolished the CRH-dependent decrease of eNOS (P < 0.001 vs CRH) and NO (P < 0.001 vs CRH), as well as the increase of catalase activity (P < 0.001 vs CRH). Moreover, both androgen amplified the CRH-dependent increase of oxidative burden (P < 0.001 vs CRH) and SOD activity (P < 0.05 vs CRH). All the above effects of androgens were abolished by flutamide suggesting action through the androgen receptor. Finally, testosterone and DHT had no significant effect on cellular GSH levels and the GSH/GSH + GSSH ratio in EA.hy926 cells.

Conclusion: Our findings indicate that in endothelial cells, In vitro, testosterone and DHT modulate the pro-oxidant effect of CRH, by relieving its inhibitory effect on eNOS and NO release and exacerbating its stimulatory effect on intracellular ROS levels as well as the SOD activity levels while restoring its stimulatory effect on catalase activity.