Time-dependent action of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) and its metabolite DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) on human chorionic gonadotropin and progesterone secretion.

Explants of human placenta were used to study the effects of two isomers of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) [p,p'-DDT and o,p'-DDT] and their DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) metabolites [p,p'-DDE and o,p'-DDE] on the secretion of progesterone and human chorionic gonadotropin (hCG). Explants were treated with 1, 10, 100 or 1000 ng/ml of each compound for 24 h or 72 h. We found opposite effects (stimulatory after short-term and inhibitory after long-term exposure) of all compounds on progesterone secretion. However, both short- and long-term exposure to all investigated compounds caused decreased hCG secretion. In conclusion, we suggest the existence of a local axis between steroid hormones and hCG in placenta. DDT (which has estrogenic properties) increases progesterone secretion and consequently decreases hCG secretion. After long-term exposure, the low level of hCG is insufficient to stimulate progesterone.