Endocrine Abstracts

In the adult animal the Leydig cells are the primary source of androgens in the male and are required to maintain fertility and male behaviour. To help towards understanding the development, control and function of these cells we have analysed the adult Leydig cell transcriptome using the SAGE technique which provides a comprehensive and quantitative gene expression profile of cells or tissues. Leydig cells were isolated from normal adult mouse testes using collagenase and the cell population was purified to about 90% using Percoll gradients. A SAGE library was prepared from the isolated cells and over 20,000 tags were sequenced, representing 5665 different genes. Of these genes 23% appeared more than once among the sequenced tags and 85% of this group could be linked to a UniGene cluster. The remaining 77% of genes were present as single copies and 66% could be linked to a UniGene cluster. The most abundant transcript present was relaxin-like factor while transcripts for the steroidogenic enzymes and epoxide metabolising enzymes were highly represented. Other non-ubiquitous transcripts highly represented included those coding for angiotensinogen precurssor, prostaglandin D synthetase, fatty acid binding protein, clusterin, phosphatidylethanolamine binding protein, VCAM and lipocalin. A number of genes associated specifically with germ cells were identified within the SAGE library and these are likely to originate from spermatazoa which contaminate percoll-purified Leydig cell populations. Data available from this Leydig cell SAGE library can now be used as a baseline to study Leydig cell development and function within the adult testis