High glucose-induced changes in steroid production in adrenal cells.
BACKGROUND
Increased activity of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in enhanced adrenocorticotropin (ACTH) and serum glucocorticoid levels, has been described in patients with diabetes mellitus and in animal models of this disease; however, altered steroid production by adrenocortical cells could result from local changes triggered by increased reactive oxygen species (ROS), induced in turn by chronic hyperglycaemia. Experiments were designed (1) to analyse the effects of incubating murine adrenocortical cells in hyperglycaemic media on the generation of oxidative stress, on steroid synthesis and on its modulation by the activity of haeme oxygenase (HO); and (2) to evaluate the effect of antioxidant treatment on these parameters.


METHODS
Y1 cells were incubated for 7 days with either normal or high glucose (HG, 30 mmol/L) concentrations, with or without antioxidant treatment. Parameters of oxidative stress and expression levels of haeme oxygenase-1 (HO-1), nitrite levels, L-arginine uptake and progesterone production were determined.


RESULTS
HG augmented ROS and lipoperoxide production, decreasing glutathione (GSH) levels and increasing antioxidant enzymes and HO-1 expression. Basal progesterone production was reduced, while a higher response to ACTH was observed in HG-treated cells. The increase in HO-1 expression and the effects on basal steroid production were abolished by antioxidant treatment. Inhibition of HO activity increased basal and ACTH-stimulated steroid release. Similar results were obtained by HO-1 gene silencing while the opposite effect was observed in Y1 cells overexpressing HO-1.


CONCLUSIONS
HG induces oxidative stress and affects steroid production in adrenal cells; the involvement of HO activity in the modulation of steroidogenesis in Y1 cells is postulated.
Astort
F
F
Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, CEFYBO (CONICET), Buenos Aires, Argentina.
Repetto
E M
EM
Martínez Calejman
C
C
Cipelli
J M
JM
Sánchez
R
R
Di Gruccio
J M
JM
Mercau
M
M
Pignataro
O P
OP
Arias
P
P
Cymeryng
C B
CB
D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000378:metabolism; D002478:Cells, Cultured; D002999:Clone Cells; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism*; D051379:Mice; D009573:Nitrites / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D011374:Progesterone / Q000378:metabolism*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D018709:Statistics, Nonparametric; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014162:Transfection; D015383:Zona Fasciculata / Q000166:cytology / Q000378:metabolism*
D009573:Nitrites; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D011374:Progesterone; D001120:Arginine; D006419:Heme Oxygenase (Decyclizing); D005947:Glucose