Identification of testosterone-regulated genes in testes of hypogonadal mice using oligonucleotide microarray.

FSH and testosterone (T) are required for normal spermatogenesis in mammalian males. These hormones regulate the function of Sertoli cells, which in turn support the differentiation of germ cells in the seminiferous tubules. The molecular targets for these hormones in the testis remain elusive. In this study, we have used hypogonadal (hpg) mice as an in vivo model to examine the actions of T on gene expression in murine testis. This expression pattern was analyzed using Affymetrix Murine GeneChip U74v.2 A, B, C (36,899 transcripts) along with Microarray Suite version 5.0, GeneSpring software, and real-time PCR. hpg mice aged 35-45 d were injected sc with 25 mg testosterone proprionate (TP) in 100 ml of sesame oil, and the animals were killed 4, 8, 12, or 24 h after TP treatments. Untreated hpg mice were used as controls. Gene expression from testes of hpg mice treated with TP was compared with that of testes of untreated hpg mice. At all experimental time points earlier than 24 h, there were more mRNAs with reduced than increased abundance in testes of hpg mice after TP treatment. This study suggests that in murine testis, the primary action of T might be to repress gene expression.