title: Heme oxygenase expression and activity in immortalized hypothalamic neurons GT1-7.
abstract: 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.
authors.affiliation: Institute of Pharmacology, Catholic University School of Medicine, Largo Francesco Vito 1, 00168 Roma, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Mores
authors.forename: Stefania
authors.initials: S
authors.lastname: Errico
authors.forename: Angela
authors.initials: A
authors.lastname: Pusateri
authors.forename: Eugenio
authors.initials: E
authors.lastname: Barone
authors.forename: Cesare
authors.initials: C
authors.lastname: Mancuso
mesh_terms: D000818:Animals; D001663:Bilirubin / Q000378:metabolism; D002461:Cell Line, Transformed; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D006427:Hemin / Q000494:pharmacology; D007031:Hypothalamus / Q000166:cytology*; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000201:enzymology*; D013997:Time Factors
chemical_list: D005938:Glucocorticoids; D006427:Hemin; D003907:Dexamethasone; D006419:Heme Oxygenase (Decyclizing); D001663:Bilirubin