TEMPERATURE EFFECT ON THE ACTION OF CORTICOTROPIN-RELEASING HORMONE (CRH) ON SECRETION OF IMMUNOREACTIVE BETA-ENDORPHIN (IR-BETA-EP) IN TM3AND 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 ce ll line that secretes ir beta EP. To monitor beta EP secretion from th ese cells we used the reverse hemolytic plaque assay. After 3.5 hr inc ubation of cells with hormone, the EC(50) of the CRH dose-response cur ve 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 CR H-stimulated beta EP release from a non-testicular cell line, AtT-20, a mouse anterior pituitary cell line. Using radioimmunoassay to measur e ir beta EP levels in the media of AtT-20 cells, the EC(50)s for the CRH dose-response curve at 34 degrees C and 37 degrees C were 0.2 nM a nd 2 nM, respectively, at 1 h. After 3.5 h this temperature dependent difference in EC(50) was still observed. These results suggest that CR H receptors or post-receptor actions in Leydig cells and anterior pitu itary corticotropes are sensitive to small temperature changes.