Changes in epididymal protein synthesis during the sexual cycle of the lizard, Lacerta vivipara

During its annual cycle, the lizard epididymis undergoes strong modifications of the secretory epithelium. These modifications previously were classified into 10 stages. The present study gives the biochemical basis of these modifications. Several parameters, such as the quantity of soluble proteins, rates of protein synthesis, and electrophoretic profiles of newly synthesized proteins and of in vitro RNA translation products were compared at 8 stages. Two-dimensional gel electrophoresis of newly synthesized tissue proteins showed that the synthesis of about 20 proteins fluctuated during the cycle. Furthermore, it revealed that the protein band L of molecular weight 19,000 identified in one-dimensional (1-D) electrophoresis was composed of at least 10 proteins. Their rate of synthesis paralleled the concentrations of their mRNA evaluated with in vitro translation. This could indicate that in this system protein synthesis is regulated by mRNA concentrations. The present analysis has confirmed that 4 different phases characterize the annual evolution of the lizard epididymis: regeneration, onset of secretory activity, hypersecretion and involution. Well-defined, newly synthesized proteins would characterize some of these phases, and could be used as markers for future detailed analysis of epididymis control.