Molecular maturation of cell adhesion systems during mouse early development

During cleavage, the mouse embryo expresses a variety of cell adhesion systems on its cell surfaces. We have reviewed biogenetic and assembly criteria for the formation of the uvomorulin/catenin, tight junction and desmosome adhesion systems as the trophectoderm differentiates. Each system reveals different mechanisms regulating molecular maturation. Adhesion processes contribute to the generation of distinct tissues in the blastocyst by modifying the expression pattern of blastomeres entering the non-epithelial inner cell mass lineage. Cell adhesion also influences the spatial organisation, but rarely the timing of expression, of proteins involved in trophectoderm differentiation.

Radio-enzymic assay of oxo steroids by their reduction with the tritiated form of reduced nicotinamide--adenine dinucleotide

A method of analysis is proposed based on the enzyme-catalysed transfer of tritium from [3H]NADH to suitable substrates. Its practicability is demonstrated on the examples of oestrone and progesterone with the respective use of the 3 beta, 17 beta- and 3 alpha, 20 beta-hydroxysteroid oxidoreductase. Specificity is tested by application to the analysis of the plasma of pregnant women and measurement of the 3H/14C ratios on purification of the enzymic reduction products.