We demonstrated in this study that liver receptor homolog-1(LRH-1) was expressed in the round spermatids in normal monkey testis, and no LRH-1 signal was observed in the Sertoli cells. After local warming (43°C) the monkey testis, however, LRH-1 expression was induced in the Sertoli cells in coincidence with activation of cytokeratin 18 (CK-18), a Sertoli cell dedifferentiated marker. Furthermore, we isolated rat primary Sertoli cells from testes at various stages of development, and treated with 43°C water in vitro. The changes in LRH-1 as well as in CK-18 expression were analyzed by Confocal immunohischemistry and Western blot. The results showed that LRH-1 was stage-dependently expressed in the Sertoli cells, no LRH-1 positive signal was detected in the cells obtained from the testes of adult rat on day 60 after birth when mature spermatozoa in the testis was completed. However, the mature Sertoli cells were warmed at the 43°C water bath for 15 min, the LRH-1 signal was remarkably induced in a time-dependent manner, just like the changes of CK-18 expression in the Sertoli cells, suggesting that the heat-induced dedifferentiation of the mature Sertoli cells might be related to LRH-1 regulation. LRH-1 expression induced by the heat treatment was completely inhibited by the addition of ERK inhibitor U0126 in the culture, indicating that the heat-induced LRH-1 expression in the Sertoli cells may be regulated via ERK1/2 activation pathway.

Testosterone was found no such effect on LRH-1 expression in the monkey and rat Sertoli cells.