The expression of estrogen receptor alpha isoform on the adenohypophyseal cell surface is regulated by 17beta-estradiol

GUTIÉRREZ, S; SOSA LDEL, V.; PETITI, J. P.; MUKDSI, J. H.; DE PAUL, A L; TORRES, A I

Huerta Grande- Córdoba

Congreso; II Reunión conjunta de Neurociencias; 2010

l7beta-estradiol (E2) activates membrane estrogen receptors (ER), but its identity remains controversial. We sought to identify ER in plasma membrane of pituitary cells and to establish if E2 modifies this subcellular localization. Pituitary cell cut- tures from female rats were treated with 10nM of E2 and ERalpha and beta agonists (PPT, DPN) for O, 5, 15 and 30min and with the inhibitors IC1l82780, PD980S9 and G66976. ERa and beta were detected by confocal microscopy (CM, using Concanava- lin A as a membrane marker), flow cytometry (FC) and electro n microscopy (EM). Also, PKCalpha and ERK1/2 were evaluated by western blot (WB). Statistical analysis: ANOVA-Fisher. By CM, ERa and ~ were detected in the nucleus and cytosol of con- trol cells, E2 or PPT for Smin increased ERa in plasma membrane, co-localizing with Concavanalina A. Only ERa was detected on cell surface with EM. By FCin all experimental conditions, 8% of lactotrophs expressed ERa on the surface, but af- ter 5min of stimulation a 20% of these positive-ERa cells showed a higher inten- sity of immunostaining. By MC and WB, PKC and ERK1/2 activation was observed. These effects were reversed by the inhibitors. These results evidence the presence of functional ERa in the plasma membrane of pituitary cells and suggest that E2 increased its expression.