Reproduction Abstracts

Cell ablation is a powerful technique for examining the role of a particular cell type in organ development and function. The utility of the technique is dependent upon the ablation being specific to one cell type and for those of us interested in the testis we have been fortunate that methods have existed for some time to ablate the germ cells and the Leydig cells. Recently we have also developed a transgenic mouse model which expresses the diphtheria toxin receptor (DTR) specifically on the Sertoli cells allowing controlled ablation of the Sertoli cells through injection of diphtheria toxin (DTX). This presentation will concentrate largely on the consequences for testis development and function of either Leydig cell or Sertoli cell ablation. In the rat a single injection of ethane dimethane sulphonate (EDS) leads to complete Leydig cell loss within 24 h. These initial studies led to the important observation that Leydig cell stem cells exist in the adult testis which will regenerate the Leydig cell population after ablation. The EDS model remains an important tool in the study of Leydig cell differentiation. Treatment with EDS has also been particularly useful for identification of Leydig cell transcripts/proteins and we recently carried out a microarray analysis using EDS which has identified a group of Leydig cell specific transcripts in the testis. Studies using the new model of Sertoli cell ablation have shown that these cells are essential for maintenance of the peritubular myoid cells in the neonate and for development of the adult population of Leydig cells. In the adult animal Sertoli cell ablation also leads to a 75% loss of Leydig cell number emphasising the continuing role of the Sertoli cell in maintaining/orchestrating adult testis function.