Caprine testicular hypoplasia associated with sexual reversion decreases the expression of insulin-like growth factor II (IGF-II) mRNA in testes

The genetic expression of insulin-like growth factor II (IGF-II) mRNA was studied in healthy adult testes and in hypoplastic testes of polled Murciano–Granadina goats by means of in situ hybridization. A positive reaction in spermatogonia, pachytene spermatocytes and a few peritubular myoid cells was observed using the ovine antisense oligonucleotide in healthy testes. The hypoplastic testes displayed a loss of germinal epithelium and a slight thickening of the basement membranes. A limited number of immature germinal cells displayed a lesser hybridization reaction, while the expression of IGF-II mRNA observed in the peritubular myoid cells was similar to that seen in healthy testes. In hypoplastic testes, IGF-II mRNA expression within germinal cells decreased with increasing hypoplasia within the seminiferous epithelium and there was no hybridization within the tubules in cases of severely disrupted spermatogenesis. These results suggest that testicular hypoplasia is associated with changes in the expression of IGF-II mRNA.