[Effects of the deafferentation of the pineal gland by bilateral ablation of superior cervical sympathetic ganglia on the autumnal recrudescence of testicular activity in mink].

The effects of deafferentation of the pineal gland on the autumnal recrudescence of testicular activity in mink raised in a natural photoperiod were studied following bilateral superior cervical ganglionectomy. Animals were operated at four different times between the end of summer and the end of autumn, i.e., when daylength at this latitude naturally decreases from 12.5 to 8.5 hrs. Deafferentation of the pineal gland on September 15 (daylength 12.5 hrs.) or October 20 (daylength 10.5 hrs.), when testis volume and plasma testosterone are normally reduced to a minimum, caused these values to remain at the same low levels during the whole observation period. In contrast deafferentation on October 28 (daylength 10 hrs.), did not present the recrudescence of testicular activity, but the rise was transitory and testis development was incomplete. Finally, when the operation was performed on December 1, during the phase of natural sexual resumption, the increases in testicular volume and plasma testosterone were not affected at all and the profiles of their subsequent variations conformed to the patterns of intact animals.