Testicular activity is restored by melatonin replacement after suprachiasmatic nucleus lesion or superior cervical ganglionectomy in mink.
Subcutaneous melatonin implants were inserted in mink subjected to natural (autumn) or experimental gonadostimulatory short-days (4L:20D), after lesion of the suprachiasmatic nucleus (SCNx) or after superior cervical ganglionectomy (SCGx). Gonad stimulation was assessed by measuring testicular volume and plasma testosterone level. In SCNx and SCGx animals, all measurements were indicative of sexual quiescence. In contrast, both SCNx and SCGx animals with melatonin, maintained in natural or experimental gonadostimulating short-days, showed an increase in testicular activity 2 months after melatonin implantation. Thus, melatonin (and pineal activity) is a prerequisite for the photoperiodic stimulation of reproductive activity, and the SCN is not necessarily the target site for melatonin action on the renewal of reproduction in the mink.
Maurel
Daniel L
DL
Pathologie de l'Oreille interne et Réhabilitation, INSERM, Faculté de Médecine Nord, Boulevard Pierre-Dramard, Marseille cedex 20, France. maurel.d@jean-roche.univ-mrs.fr
Ben Saad
Mohamed Moncef
MM
Roch
Gisèle
G
Siaud
Philippe
P
D000818:Animals; D003714:Denervation; D015171:Ganglionectomy; D008297:Male; D008550:Melatonin / Q000008:administration & dosage* / Q000502:physiology; D008907:Mink; D017440:Photoperiod; D010870:Pineal Gland / Q000502:physiology; D012098:Reproduction / Q000502:physiology; D012621:Seasons; D017783:Superior Cervical Ganglion / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000293:injuries / Q000502:physiology*; D013737:Testis / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology*; D013739:Testosterone / Q000097:blood
D013739:Testosterone; D008550:Melatonin