Immunocytochemical identification of growth hormone-releasing hormone during the ontogeny of pejerrey, Odontesthes bonariensis.

MIRANDA, L.A.; STROBL-MAZZULLA, P.H.; SOMOZA, G.M.

Villa Carlos Paz, Argentina.

Congreso; XXXVII Annual Meeting of the Argentine Society of Biochemistry and Molecular Biology Research; 2001

The presence of growth-hormone releasing hormone (GHRH) was studied by immunocytochemistry in adult and developing pejerrey fish. A few neurons and fibers were identified in the olfactory bulbs at hatching. One week after hatching (1WAH) scattered ir-GhRH neurons were observed in the preoptic area and some fibers were detected entering to the pituitary gland. At 3WAH isolated ir-GHRH neurons were revealed in the hypothalamus and in the medulla. Then ir-GHRH  cells were identified at the nucleus of the lateral lemniscus and the cerebellum. Both nuclei of neurons presented strong ir-GHRH projection extending rostro-ventrally. At 11 WHA another group of ir-GHRH cells could be revealed at the midbrain tegmentum. Since then the pattern of distribution of ir-GHRH structures remained unchanged. The pituitary gland revealed ir-GHRH cells and fibers mainly in the proximalis pars distalis and in a minor proportion in the pars intermedia since week 1. The pineal gland showed ir-GHRH cells projecting into the pineal lumen, since 6WAH. Also the pineal stalk and the subcomissural organ presented ir-GHRH structures. Additionally, ir-GHRH material was found since week 3 in the following extraneural organs: gills, gut, kidney and hepatopancreas. These results represent the anatomical substrate to understand the physiology of GHRH peptide in pejerrey.