ANDROGEN RECEPTOR IN PITUITARY PARS DISTALIS OF VISCACHA: QUANTITATIVE ANALYSIS DURING LONG AND SHORT PHOTOPERIODS

ROSALES GABRIELA; BUSOLINI FABRICIO; FILIPPA VERÓNICA; MOHAMED FABIAN

La Falda, Cordoba.

Congreso; XIX Jornadas Científicas. Sociedad de Biología de Córdoba.; 2013

Sociedad de Biología de Córdoba.

The viscacha is a seasonal reproduction rodent. The environmental photoperiod synchronizes the annual reproductive cycle of male adults. They have variables androgen levels during the annual reproductive cycle. The androgen receptor (AR) is activated by high affinity binding of testosterone. The aim of this work was to study the expression of AR in different areas of pituitary pars distalis (PD) of adult male viscacha during long (summer, n = 4) and short (winter, n = 4) photoperiods. AR were immunostained with anti-AR (N-20) and the biotin-streptavidin system. Labeled nuclei were counted and expressed as percentage of the total number of cells/microscopic field. It was shown that AR localization in pituitary PD was most abundant at the caudal end during the reproductive period. There were seasonal variations between LP (reproductive period) and SP (gonadal regression period) in some PD zones. These results suggest that the pituitary expression of AR varies with testosterone levels, probably by regulating the activity of pituitary cells involved in the reproductive axis.