TESTOSTERONE INCREASES CELL PROLIFERATION IN PITUITARY PARS DISTALIS OF VISCACHA

ROSALES GABRIELA; BUSOLINI FABRICIO; FILIPPA VERÓNICA; MOHAMED FABIAN

San Miguel de Tucumán

Congreso; Tercera Reunión Conjunta de Sociedades de Biología de la República Argentina; 2015

Sociedad de Biología de Argentina

The proliferative activity of the adenohypophysis has been related to circadian variations and to the effects of sex steroids. The aim ofthis work was to study cell proliferation in pituitary pars distalis (PD) of adult male viscachas during the reproductive period andgonadal regression period. Four viscachas were captured during the reproductive period (summer and early autumn) and four duringthe gonadal regression period (winter). The proliferating cell nuclear antigen (PCNA) and androgen receptor (AR) were located andquantified by immunohistochemistry and image analysis. Testosterone serum levels were determined by chemiluminescence enzymeimmuoassay. The percentages of PCNA-ir (immunoreactive) cells and AR-ir cells were significantly higher during the reproductiveperiod (PCNA-ir: 8.68 ± 1.18% and AR-ir: 8.05 ± 0.82%) than those found during the gonadal regression period (PCNA-ir: 2.42 ±0.26% and AR-ir: 2.34 ± 0.34%). Testosterone levels were significantly higher during the reproductive period (4.24 ± 0.47 ng/mL)than the ones during the gonadal regression period (1.27 ± 0.10 ng/mL). These results demonstrate that in PD of adult male viscachascell proliferation is directly related to testosterone serum levels and to the expression of their receptors during the periods of maximaland minimal gonadal activity. Testosterone serum levels through their specific receptors might stimulate cell proliferation during thereproductive period, which is when glandular activity is increased in the pituitary PD of viscacha