Affiliation: | * Groupe de Recherche en Endocrinologie Moléculaire, UA CNRS 650, Unité Alliée à l'INSERM Faculté des Sciences, Université de Rouen, 76130, Mont Saint Aignan, France † MRC Group in Molecular Endocrinology, Le Centre Hospitalier de l'Université Laval Québec, G1V 4G2, Canada ‡ Kantonsspital Basel, Universitätskliniken, Department Forschung Hebelstrasse 20 CH 4031, Basel, Switzerland |
Abstract: | The distribution of melanin-concentrating hormone (MCH) in the central nervous system of the frog Rana ridibunda was determined by the indirect immunofluorescence technique using antibodies against synthetic salmon MCH, generated in rabbits. The most prominent group of MCH-like containing perikarya was detected in the preoptic nucleus. Comparatively, a moderate number of cell bodies was observed in the dorsal infundibular nucleus and in the ventral thalamic area. Brightly immunofluorescent nerve bundles were found in the preoptic nucleus and in the ventral infundibular nucleus, coursing towards the internal zone of the median eminence and the pituitary stalk. An intense network of immunofluorescent fibers was localized in the neural lobe of the pituitary. The subcellular localization of MCH-like material was studied in the neurohypophysis using the immunogold technique. It was demonstrated that MCH-like material was contained in dense core vesicles (80–90 mm in diameter) within specific nerve terminals. The present findings indicate that, in amphibians, MCH-like peptide is located in specific hypothalamic neurons. Our data suggest that MCH may be released by neurohypophyseal nerve endings as a typical neurohormone. |