Abstract
With combined immunoperoxidase and immunofluorescence, we observed colocalization
of cytochrome P450 aromatase with the posterior lobe peptide oxytocin and its associated
neurophysin 1 in adult male rats. P450 was most abundant in the anterior hypothalamus.
Colocalization of OT with P450 was observed in the preoptic region, the periventricular
nucleus of the hypothalamus, the lateral subcommissural nucleus, and in the zona incerta.
Magnocellular perikarya in the supraoptic and in the paraventricular nuclei contained
only occasionally both antigens. P450 immunostaining overlapped to a great extent
with known estrogen target regions. Oxytocinergic functions are controlled by estradiol
while androgen receptors are mostly absent in neuroendocrine hypothalamic nuclei.
Our findings suggest that systemic androgens may be aromatized to estrogens in male
oxytocinergic neurons linked to the limbic system.
Key words
hypothalamus - androgens - oxytocin - aromatase - limbic system - pituitary
