Heme oxygenase expression and activity in immortalized hypothalamic neurons GT1–7

• Published in: Neuroscience letters Vol. 444; no. 1; pp. 106 - 108
• Main Authors: Mores, Nadia, Errico, Stefania, Pusateri, Angela, Barone, Eugenio, Mancuso, Cesare
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 17.10.2008; Elsevier
• Subjects: Animals; Bilirubin; Bilirubin - metabolism; Biological and medical sciences; Carbon monoxide; Cell Line, Transformed; Dexamethasone - pharmacology; Fundamental and applied biological sciences. Psychology; Glucocorticoids - pharmacology; Gonadotropin releasing hormone; GT1–7 cells; Heme oxygenase; Heme Oxygenase (Decyclizing) - metabolism; Hemin - pharmacology; Hypothalamic neurons; Hypothalamus - cytology; Mice; Neurons - drug effects; Neurons - enzymology; Time Factors; Vertebrates: nervous system and sense organs; Bilirubin; Carbon monoxide; Gonadotropin releasing hormone; Hypothalamic neurons; Heme oxygenase; GT1–7 cells; Oxygenase; Bilirubin;Carbon monoxide;Heme oxygenase;Hypothalamic neurons;Gonadotropin releasing hormone;GT1-7cells; Neuron; Enzyme; Central nervous system; Heme; Oxidoreductases; Hypothalamus; Encephalon
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2008.08.016

Heme oxygenase (HO), the main enzyme deputed to heme metabolism, has been identified as two main isoforms called HO-1 and HO-2. HO-1 is inducible and plays a main role in the cellular oxidant/antioxidant balance whereas HO-2 is constitutive and involved in the physiological metabolism of heme. However, it is noteworthy to mention that HO contribute to the regulation of the hypothalamic release of neuropeptides such as corticotrophin-releasing hormone and arginine-vasopressin and could modulate the pulsatile release of gonadotropin releasing hormone (GnRH). GT1–7 cells are immortalized hypothalamic neurons and a valuable tool to evaluate hypothalamic neuroendocrine control of reproduction. The aim of this work was to investigate and characterize the presence of HO isoforms in the GT1–7 hypothalamic neurons. Hemin, a well-known inducer of HO-1, significantly increased HO activity, whereas dexamethasone did not modify HO-2 activity. Moreover, hemin and DEX, in combination, did not have any additive effect on HO activity in GT1–7 neurons. Furthermore, basal HO-1 immunoreactivity identified in GT1–7 cells, was significantly up-regulated by hemin. Conversely, no HO-2 immunoreactivity was detected. Taken together, these results suggest the presence of functional HO-1 in GT1–7 immortalized hypothalamic neurons and open new avenues about the use of this cell line for the study of HO modulation of GnRH secretion and reproduction.