GELATINASE-A SECRETION AND ITS CONTROL IN PERITUBULAR AND SERTOLI-CELL CULTURES - EFFECTS OF HORMONES, 2ND-MESSENGERS AND INDUCERS OF CYTOKINE PRODUCTION

Extracellular matrix components as well as enzymes and enzyme-inhibito rs controlling the turn-over of these components play an important rol e in the local control of testicular function. Zymographic analysis wa s used to study the secretion and the control of the secretion of gela tinase A (MMP-2) and B (MMP-9) by primary cultures of rat Sertoli cell s and by subcultures of peritubular cells. Data on gelatinase A were c omplemented by measurement of the corresponding mRNA by Northern blot analysis. The agonists investigated included hormones (FSH, testostero ne), second messengers (dbcAMP, phorbolester and a Ca2+-ionophore). in terleukin-1 beta (IL-1 beta) and inducers of cytokine production (Conc anavalin A: ConA: lipopolysaccharide: LPS: double stranded RNA: PIG). It is demonstrated that Sertoli cells originally secrete both gelatina se A and B. When maintained in serum-free medium, however, they rapidl y lose the ability to secrete gelatinase B. After 3 days of culture ge latinase A remains the only measurable gelatinase in both Sertoli and peritubular cell cultures. The production in peritubular cells, howeve r, exceeds that in Sertoli cells some 25-fold. This was confirmed by a 30-fold difference in the level of steady-state gelatinase A mRNA lev els Gelatinase A secretion and gelatinase A mRNA were stimulated by ov ine FSH in Sertoli cells and by dbcAMP and ConA in both Sertoli and pe ritubular cells. IL-1 beta displayed measurable but limited stimulator y effects in both cell types. Interestingly, in peritubular cells but not in Sertoli cells, ConA stimulated the production of a lower MW spe cies probably representing an activated form of gelatinase A. It is co ncluded that both the amounts of gelatinase A produced, the levels of the corresponding mRNA and the regulation differ in cultured peritubul ar cells and Sertoli cells. The lectin concanavalin A is a novel and p otent inducer of gelatinase A. It resembles cytochalasin D in selectiv ely inducing an activated form of gelatinase A in peritubular cells. T he mechanism responsible for this selective effect warrants further in vestigation.