Epidermal growth factor and the regulation of amnion prostaglandin biosynthesis.

The production of prostaglandins by amnion is a key factor in the mechanism of human parturition yet the regulation of prostaglandin biosynthesis in amnion is poorly understood. Hence, we have investigated the regulation of epidermal growth factor (EGF) stimulation of prostaglandin biosynthesis in human amnion cells. This stimulatory action is inhibited by cycloheximide or actinomycin D at high concentrations, but enhanced at much lower concentrations of these protein synthesis inhibitors.

Actions of endothelin-1 on prostaglandin production by gestational tissues.

Endothelin-1 (10(-11)M-10(-7)M) was incubated with human umbilical vein endothelial cells and cells derived from amnion and decidua and prostaglandin production was determined. The rates of biosynthesis of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and prostaglandin E2 (PGE2) by endothelial cells were increased significantly by treatment with endothelin-1. Amnion cell PGE2 production was reduced significantly by endothelin-1 treatment whereas decidual PGE2 and prostaglandin F2 alpha production was unaffected by this treatment.

Morphogenesis of precursor subpopulations of chicken limb mesenchyme in three dimensional collagen gel culture.

Although homogeneous in appearance, several lines of evidence suggest early (stage 17-19) limb mesenchymal cells are committed to particular cell lineages, e.g., myogenic or chondrogenic.

Initial expression of type I procollagen in chick cardiac mesenchyme is dependent upon myocardial stimulation.

Formation of the atrioventricular (AV) mesenchyme is a critical step in early heart development. Endothelial cells are activated and transformed into a mesenchymal population that invades the cell-free myocardial basement membrane. This process can be duplicated in collagen gel culture, where it has been established that myocardium or its secretory products activate the endothelium.

Myocardial specificity for initiating endothelial-mesenchymal cell transition in embryonic chick heart correlates with a particulate distribution of fibronectin.

The early chick heart tube consists of myocardium and endothelium separated by a myocardially derived basement membrane (MBM). As development proceeds, the endothelium undergoes a transition into mesenchyme in a regionally specific manner; only the atrioventricular (AV) and outflow tract, but not the ventricular endothelium, is transformed into mesenchyme, the progenitor of heart septa and valves. Recent experiments have shown that an EDTA extract of MBM can initiate AV endothelium to form mesenchyme in an in vitro collagen gel culture system.