Estrogen Synthesis

Most vertebrates express an enzyme, called aromatase, in parts of the brain, that converts androgens into estrogens. We know that many actions of circulating Testosterone on the brain are due to estrogens that are produced locally in the brain from those androgens in blood. Songbirds express unusually high amounts of aromatase in the brain, especially in areas that might be involved in learning and memory (the hippocampus), auditory processing and song production (telencephalon), in addition to areas involved in reproduction (hypothalamus). At the anatomical level, we are examining which cells express aromatase and where the aromatase protein is found. Some of our current research is stimulated by our hypothesis that aromatase is found within synaptic terminals and elevated estrogen levels in and around the synapse influence pre- and/or post-synaptic physiology. We have studied brain aromatase in several species of wild and captive birds, and even in a unique species of fish (in collaboration with Andrew Bass).

Examples of aromatase in situs.