Figure 4

Effect of increasing concentrations of D-Asp (1.0–2.0 mM) and of L-Arg (1.0–2.0 mM) on testosterone release from testes of A. platyrhynchos . The testis slices were incubated for 60 (□) or 120 (■) min. Testosterone levels were enhanced after 60 or 120 min incubation with D-Asp, whereas they were inhibited in the presence of L-Arg. The level of significance was taken at p < 0.05 (*) and p < 0.01 (* *) versus respective controls.