title: Opposite effects of dihydrotestosterone and estradiol on apoptosis in the anterior pituitary gland from male rats.
abstract: Hormones locally synthesized in the anterior pituitary gland are involved in regulation of pituitary cell renewal. In the pituitary, testosterone (T) may exert its actions per se or by conversion to dihydrotestosterone (DHT) or 17β-estradiol (E2) by 5α-reductase and aromatase activity, which are expressed in this gland. Previous reports from our laboratory showed that estrogens modulate apoptosis of lactotropes and somatotropes from female rats. Now, we examined the in vitro and in vivo effects of gonadal steroids on apoptosis of anterior pituitary cells from adult male rats. T in vitro did not modify apoptosis in anterior pituitary cells from gonadectomized (GNX) male rats. DHT, a non-aromatizable androgen, exerted direct antiapoptotic action on total anterior pituitary cells and folliculo-stellate cells, but not on lactotropes, somatotropes, or gonadotropes. On the contrary, E2 exerted a rapid apoptotic effect on total cells as well as on lactotropes and somatotropes. Incubation of anterior pituitary cells with T in presence of Finasteride, an inhibitor of 5α-reductase, increased the percentage of TUNEL-positive cells. In vivo administration of DHT to GNX rats reduced apoptosis in the anterior pituitary whereas E2 exerted proapoptotic action and reduced cells in G2/M-phase of the cell cycle. In summary, our results indicate that DHT and E2 have opposite effects on apoptosis in the anterior pituitary gland suggesting that local metabolization of T to these steroids could be involved in pituitary cell turnover in males. Changes in expression and/or activity of 5α-reductase and aromatase may play a role in the development of anterior pituitary tumors.
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: María Laura
authors: ML
authors: Magri
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: María Florencia
authors: MF
authors: Gottardo
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: Sandra
authors: S
authors: Zárate
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: Guadalupe
authors: G
authors: Eijo
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: Jimena
authors: J
authors: Ferraris
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: Gabriela
authors: G
authors: Jaita
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: Mariela Moreno
authors: MM
authors: Ayala
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: Marianela
authors: M
authors: Candolfi
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina.
authors: Daniel
authors: D
authors: Pisera
authors: Instituto de Investigaciones Biomédicas (UBA-CONICET), Paraguay 2155, C1121ABG, Buenos Aires, Argentina. adyseili@fmed.uba.ar.
authors: Adriana
authors: A
authors: Seilicovich
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis; D001141:Aromatase / Q000378:metabolism; D002478:Cells, Cultured; D013196:Dihydrotestosterone / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D018120:Finasteride / Q000494:pharmacology; D008297:Male; D009919:Orchiectomy; D010903:Pituitary Gland, Anterior / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000494:pharmacology
chemical_list: D000728:Androgens; D051017:Apoptosis Regulatory Proteins; D004791:Enzyme Inhibitors; D004967:Estrogens; D013196:Dihydrotestosterone; D013739:Testosterone; D004958:Estradiol; D018120:Finasteride; D001141:Aromatase; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase
keywords: 5α-reductase; Androgens; Apoptosis; Aromatase; Estrogens; Pituitary