The action of dexamethasone and prolactin on aromatase activity in human adipose tissue.

Using slices of human adipose tissue maintained in medium 199 for 40 h at 37 degrees C, it was observed that in the absence of any other additions, the presence of foetal calf serum (10%) inhibits basal levels of aromatase activity. Including dexamethasone (1 X 10(-7) M) in the medium increases aromatase activity approximately 10-fold in the presence of foetal calf serum but has only a small stimulatory effect in its absence. The combined addition of dexamethasone (1 X 10(-7) M) and human prolactin (0.8 ng/ml) has a marked additional incremental effect in the presence or absence of foetal calf serum. In contrast, the addition of prolactin to the medium without glucocorticoid did not stimulate oestrogen production. The possibility that prolactin could be the substance in foetal calf serum responsible for mediating the stimulatory effect of glucocorticoids on oestrogen production is considered.