Regulation of progesterone production in human term trophoblasts in vitro by CRH, ACTH and cortisol (prednisolone).

BACKGROUND

In most mammals, onset of labor is accompanied with progesterone withdrawal. In humans, cortisol blockade of progesterone is a possible mechanism involved in the initiation of labor. Therefore, aim of the study was to clarify the effect of CRH, ACTH and cortisol (prednisolone) on the release of progesterone by term trophoblast cells in vitro.

METHODS

Cytotrophoblast cells were prepared from human term placentas by standard dispersion of villous tissue followed by a percoll gradient centrifugation step. Trophoblasts were incubated with CRH, ACTH as well as with prednisolone.

RESULTS

The release of progesterone is decreased in CRH- and ACTH-treated trophoblast cell cultures compared to untreated trophoblast cells. Addition of prednisolone in varying concentrations leads to an increase of trophoblast progesterone production.

CONCLUSIONS

The results suggest that CRH and ACTH directly modulate the endocrine function of trophoblasts in culture by downregulating progesterone production. Prednisolone on the other hand showed a stimulating effect on progesterone production in term trophoblast cells in vitro. Because blockade of progesterone is a possible mechanism involved in initiation of labor, we may speculate that CRH and ACTH are directly involved in the auto- or paracrine regulation of this procedure.