Aromatization in the neural target tissues of the female frog, Rana esculenta: seasonal studies

Abstract

It is well known that certain actions of androgen are mediated through in situ brain aromatization to estrogen. This study was undertaken to investigate seasonally the androgen utilization in the neural target tissues of the female frog, Rana esculenta, through a quantification of aromatase activity and estrogen receptors (ER). Aromatase activity was detected in the microsomal fraction of the brain and co-localization with ER was only in the cytoplasmatic area. Western analysis of aromatase revealed one immunoreactive band with a molecular weight of approximately 56 kDa. ER were present seasonally in both the cytosol and the nuclear brain extracts. Data on aromatase enzyme activity and relative levels of aromatase protein are discussed and more detail on the mechanisms involved in frog brain regulating estrogen synthesis supposed. Further studies are in progress to cloning the sex steroid-synthesizing enzyme CYP19 in the neural target tissues of Rana esculenta.