L. Forró szerk.: Miscellanea Zoologica Hungarica 7. 1992 (Budapest, 1992)

Gubányi, A., Kéri, Gy. , Fehér, T.; Pekli, J.: A chicken GnRH analogue (Folligen) stimulates plasma testosterone level and sexual activity in the male marsh frog during and out of spawning season - Preliminary notes

Results Figure 1. summarizes the changes in plasma testosterone level (T) of males throughout the short-term studies (summer, winter and spring experiments). Plasma T levels were significantly raised by all GnRHa doses of all experiments (P<0.05 except 1 p.g/animal/day treatment, P

=0.062). No dose-dependent response of plasma T levels to different GnRH quantity was found in frogs tested in summer (P=

0.364). The relative increment of plasma T was the greatest among frogs treated in winter (1620 %). GnRHa (Folligen) also increased plasma T levels in animals ready to mate in spring (P<0.01). Plasma estradiol levels (Fig. 2) did not show a significant decrease after the GnRHa administrations (P>0.6). Testosterone-estradiol ratios (Fig. 3) increased dramatically in GnRHa treated summer frogs (P<0.05). Among frogs tested in summer, only those which were treated with 100 ng GnRHa/day showed sexual activity, such as calling and territorial behaviour (fighting). At the same time males were in amplexus with test females both in winter and spring experiments about 12 hours after the third injection. Fig. 1. Effect of different GnRHa treatment on plasma testosterone level in marsh frogs. Vertical bars represent means SEM (G = GnrHa; * = treatment lasted for 6 days; ** = frogs were treated with GnRHa for 3 days; 1st day: 250 ng/g BW, 2nd day: 500 ng/g BW, 3rd day: 1000ng/g BW, *** = frogs were treated with GnRHa for 3 days; 1st day: 0.25 ng/g BW, 2nd day: 0.5 ng/g BW, 3rd day: lng/g BW)