SYNERGISTIC CONTROL BY ANDROGENS AND ESTROGENS OF AROMATASE IN THE QUAIL BRAIN

CASTRATED quail were injected with testosterone or with the synthetic hormones diethylstilbestrol (DES) or methyltrienolone (R1881)to analys e the steroid specificity in the induction of brain aromatase. R1881 p roduced a moderate (generally non-significant) increase in the number of aromatase-immunoreactive cells. DES significantly increased the num ber of positive cells in most brain areas. A clear synergism between D ES and R1881 was observed in all brain regions: more immunoreactive ce lls were found in birds receiving both compounds than in those injecte d with DES or R1881 alone. DES and R1881 are highly specific ligands f or oestrogen and androgen receptors respectively. It appears likely th at both androgens and oestrogens directly modulate brain aromatase, pr esumably at the transcription level.