DEVELOPMENTAL REGULATION OF SERTOLI-CELL LACTATE PRODUCTION BY HORMONES AND THE TESTICULAR PARACRINE FACTOR, PMODS

Testicular peritubular cells produce a paracrine factor termed PModS t hat mediates mesenchymal-epithelial interactions and modulates Sertoli cell functions essential for the process of spermatogenesis. Sertoli cells produce lactate as a preferred energy metabolite for developing spermatogenic cells. The current study was designed to examine the act ions of PModS and hormones on Sertoli cell lactate production at vario us stages of pubertal development. Sertoli cells were isolated from pr e-pubertal (10 day), mid-pubertal (20 day) and late pubertal (35 day) rat testes. Lactate accumulation in the conditioned-medium of cultured Sertoli cells was measured. Basal lactate production increased approx imately fivefold during pubertal Sertoli cell development. Therefore, lactate production increases as the Sertoli cell differentiates during pubertal development. The ability of regulatory agents such as FSH or a combination of FSH, insulin, retinol and testosterone (FIRT) to sti mulate lactate production decreased during pubertal development as Ser toli cell differentiation increased. Purified PModS stimulated lactate production in Sertoli cell preparations throughout pubertal developme nt. PModS had a greater effect than FSH in stimulating late pubertal S ertoli cell lactate production. PModS in combination with FIRT resulte d in an additive stimulation of lactate production suggesting a distin ct mechanism of action for PModS. Observations support the proposal th at the locally produced paracrine factor PModS mediates mesenchymal-ep ithelial cell interactions during pubertal development and that these interactions promote Sertoli cell differentiated functions (i.e. lacta te production) required for the developing spermatogenic cells.