Opposite effects of dihydrotestosterone and estradiol on apoptosis in the anterior pituitary gland from male rats

MAGRI ML; GOTTARDO MF; ZARATE S; EIJO G; FERRARIS J; JAITA G; MORENO AYALA M A; CANDOLFI M; SEILICOVICH A

ENDOCRINE

HUMANA PRESS INC

Lugar: Oregon; Año: 2015 vol. 51 p. 506 - 516

0969-711X

Hormones locally synthesized in the anteriorpituitary gland are involved in regulation of pituitary cellrenewal. In the pituitary, testosterone (T) may exert itsactions per se or by conversion to dihydrotestosterone(DHT) or 17b-estradiol (E2) by 5a-reductase and aromataseactivity, which are expressed in this gland. Previousreports from our laboratory showed that estrogens modulateapoptosis of lactotropes and somatotropes from femalerats. Now, we examined the in vitro and in vivo effects ofgonadal steroids on apoptosis of anterior pituitary cellsfrom adult male rats. T in vitro did not modify apoptosis inanterior pituitary cells from gonadectomized (GNX) malerats. DHT, a non-aromatizable androgen, exerted directantiapoptotic action on total anterior pituitary cells andfolliculo-stellate cells, but not on lactotropes, somatotropes,or gonadotropes. On the contrary, E2 exerted arapid apoptotic effect on total cells as well as on lactotropesand somatotropes. Incubation of anterior pituitarycells with T in presence of Finasteride, an inhibitor of 5areductase,increased the percentage of TUNEL-positivecells. In vivo administration of DHT to GNX rats reducedapoptosis in the anterior pituitary whereas E2 exertedproapoptotic action and reduced cells in G2/M-phase of thecell cycle. In summary, our results indicate that DHT andE2 have opposite effects on apoptosis in the anterior pituitarygland suggesting that local metabolization of T tothese steroids could be involved in pituitary cell turnover inmales. Changes in expression and/or activity of 5areductaseand aromatase may play a role in the developmentof anterior pituitary tumors.