The maintenance of rat metrial gland explants in vitro, in the presence and absence of progesterone.

Explants of metrial gland were taken from uteri of rats at day 13 of pregnancy and maintained in vitro for up to 9 days. Some cultures were supplemented with progesterone. The progress of the explants was monitored by light and electron microscopy. In the absence of progesterone, large amounts of collagen were apparent and many cells contained lipid inclusions. The granulated cells which are characteristic of the gland were not seen after 4 days in culture. In the presence of progesterone, though apparently normal granulated cells were readily found after 4 days in culture and could be identified after 9 days, some showed changes which do not occur in vivo. Collagen accumulation and the development of lipid inclusions were less extensive in the presence of progesterone.