The effect of insulin on oestradiol and progesterone release by normal and diabetic placentae in vitro.

In an attempt to define better the metabolic differences between normal, insulin-dependent and non-insulin-dependent diabetes, we have compared the effect of insulin on the secretion of oestradiol and progesterone in term placental explant culture. Placentae from non-diabetic and from diabetic, non-insulin-dependent diabetic patients demonstrated a similar response to incubation with insulin. This response consisted of a dose-dependent increase in both oestradiol and progesterone in the incubation media after 24 h. In contrast, the placentae of insulin-dependent diabetics showed a decrease in oestradiol and no change in progesterone secretion following exposure to insulin. These differences in response to insulin may underlie other metabolic differences between the placentae in the different groups.