SEASONAL-CHANGES OF TESTICULAR PARAMETERS IN SOUTHERN PUDU PUDU-PUDA IN RELATIONSHIP TO CIRCANNUAL VARIATION OF ITS REPRODUCTIVE HORMONES

Seasonal variation of testicular and epididymal parameters in the smal lest deer, the southern pudu Pudu puda Molina, 1782 were related to th e circannual fluctuation of plasma levels of its reproductive hormones . The diameter and the length of testes, the diameter of epididymis as well as the diameter and the heights of epithelium of seminiferous an d epididymal tubules were measured. Morphological evaluation of sperma togenesis were performed on histological sections of testicular and ep ididymal tissues. Most of these gonadal parameters exhibit a seasonal variation which is in accordance with the reproductive pattern as well as the variation of reproductive hormones. Seasonal fluctuations of L H and testosterone indicate two seasonal activations of the reproducti ve system, one in the spring (antler mineralization), the other in the fall (rut). FSH exhibit one prolonged peak (summer to fall) whereas p rolactin follows the expected, photoperiodically-dependant time course with peak levels around the summer solstice. The measurements of test icular parameters indicate a prolonged period of gonadal activity in s outhern pudu but the period of maximal reproductive stimulation is lim ited to the time around the rut.