In situ hybridization histochemistry: a technique for the study of gene expression in single cells.

The patterns of growth hormone and proopiomelanocortin gene expression in the rat pituitary were used to detail the application of the in situ hybridization histochemistry technique in tissue sections. Parameters affecting the efficiency and resolution of hybridization have been optimized so that this technique can be used to identify sites of peptide synthesis and to study hormonal regulation of gene expression at the single cell level.