Temperature effect on the action of corticotropin-releasing hormone (CRH) on secretion of immunoreactive beta-endorphin (IR beta EP) in TM3 and AtT-20 cell lines.

Testicular function is sensitive to chemical and thermal stresses. To investigate the effects of small temperature changes on CRH-stimulated beta EP release, we employed TM3 cells, a mouse prepubertal Leydig cell line that secretes ir beta EP. To monitor beta EP secretion from these cells we used the reverse hemolytic plaque assay. After 3.5 hr incubation of cells with hormone, the EC50 of the CRH dose-response curve at 34 degrees C and 37 degrees C were 0.1 nM and 1 nM, respectively. For comparison, we also investigated the effect of temperature on CRH-stimulated beta EP release from a non-testicular cell line, AtT-20, a mouse anterior pituitary cell line. Using radioimmunoassay to measure ir beta EP levels in the media of AtT-20 cells, the EC50s for the CRH dose-response curve at 34 degrees C and 37 degrees C were 0.2 nM and 2 nM, respectively, at 1 h. After 3.5 h this temperature dependent difference in EC50 was still observed. These results suggest that CRH receptors or post-receptor actions in Leydig cells and anterior pituitary corticotropes are sensitive to small temperature changes.