TY - JOUR
T1 - Antidepressant fluoxetine enhances glucocorticoid receptor function in vitro by modulating membrane steroid transporters
AU - Pariante, C M
AU - Kim, R B
AU - Makoff, A
AU - Kerwin, R W
PY - 2003/7
Y1 - 2003/7
N2 - 1 Incubation of LMCAT fibroblast cells with antidepressants potentiates glucocorticoid receptor (GR)-mediated gene transcription in the presence of dexamethasone and cortisol, but not of corticosterone. We have shown that antidepressants do so by inhibiting the LMCAT cell membrane steroid transporter ( which is virtually identical to the multidrug resistance P-glycoprotein) and thus by increasing dexamethasone or cortisol intracellular concentrations. However, previous experiments with the antidepressant fluoxetine in the presence of dexamethasone have produced negative results (Pariante et al. ( 2001). Br. J. Pharmacol., 134, 1335 - 1343). 2 We have since re-examined the effects of fluoxetine on GR-mediated gene transcription in the presence of dexamethasone. Moreover, we have examined the effects of fluoxetine on GR-mediated gene transcription in the presence of cortisol and corticosterone, and on the intracellular accumulation of radioactive cortisol and corticosterone. Finally, we have examined the effects of fluoxetine on inhibition of P-glycoprotein activity in Caco-2 cells. 3 We now find that fluoxetine ( 1 - 10 mm) enhances GR-mediated gene transcription in the presence of dexamethasone and cortisol (+140 - 170%), but not of corticosterone, and increases the intracellular accumulation of H-3-cortisol (+5 - 15%), but not of H-3-corticosterone. Moreover, fluoxetine (10 muM) induces approximately 30% inhibition of PGP activity in Caco-2 cells. 4 Our results show that fluoxetine, like other antidepressants, inhibits membrane steroid transporters.
AB - 1 Incubation of LMCAT fibroblast cells with antidepressants potentiates glucocorticoid receptor (GR)-mediated gene transcription in the presence of dexamethasone and cortisol, but not of corticosterone. We have shown that antidepressants do so by inhibiting the LMCAT cell membrane steroid transporter ( which is virtually identical to the multidrug resistance P-glycoprotein) and thus by increasing dexamethasone or cortisol intracellular concentrations. However, previous experiments with the antidepressant fluoxetine in the presence of dexamethasone have produced negative results (Pariante et al. ( 2001). Br. J. Pharmacol., 134, 1335 - 1343). 2 We have since re-examined the effects of fluoxetine on GR-mediated gene transcription in the presence of dexamethasone. Moreover, we have examined the effects of fluoxetine on GR-mediated gene transcription in the presence of cortisol and corticosterone, and on the intracellular accumulation of radioactive cortisol and corticosterone. Finally, we have examined the effects of fluoxetine on inhibition of P-glycoprotein activity in Caco-2 cells. 3 We now find that fluoxetine ( 1 - 10 mm) enhances GR-mediated gene transcription in the presence of dexamethasone and cortisol (+140 - 170%), but not of corticosterone, and increases the intracellular accumulation of H-3-cortisol (+5 - 15%), but not of H-3-corticosterone. Moreover, fluoxetine (10 muM) induces approximately 30% inhibition of PGP activity in Caco-2 cells. 4 Our results show that fluoxetine, like other antidepressants, inhibits membrane steroid transporters.
UR - http://www.scopus.com/inward/record.url?scp=0042168887&partnerID=8YFLogxK
U2 - 10.1038/sj.bjp.0705357
DO - 10.1038/sj.bjp.0705357
M3 - Article
SN - 1476-5381
VL - 139
SP - 1111
EP - 1118
JO - British Journal of Pharmacology
JF - British Journal of Pharmacology
IS - 6
ER -