Tonic ERK signaling regulate the basal lactate production in prepubertal rat Sertoli cell

Sertoli cells are the major nurse cells in the testis which regulate the division and differentiation of germ cell by secreting various factors like inhibin B, transferrin and lactate. In this study, we demonstrated that inhibition of extracellular signal-regulated kinase (ERK) leads to an increase in the basal level of lactate. This increase in lactate production was due to the rise in lactate dehydrogenase (LDH) activity and glucose uptake, simultaneously. Moreover, an increase in lactate production wasnot due to the change in mRNA level of GLU1, GLUT3 and LDHA. Importantly, the lactate production was independent of the level of cAMP suggesting that the tonic signaling of ERK is important for the growth factor mediated lactate production. These findings suggest that ERK signaling inhibits lactate production in the absence of any stimulant in rat Sertoli cells to maintain metabolic homeostasis.