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Title: IDENTIFICATION OF GROWTH HORMONE-, AND PROLACTIN-CONTAINING NEURONS WITHIN THE AVIAN BRAIN

Author
item RAMESH, R - UNIVERSITY OF MARYLAND
item KUENZEL, W - UNIVERSITY OF MARYLAND
item BUNTIN, J - UNIV OF WISCONSIN-MADISON
item Proudman, John

Submitted to: Journal of Comparative Neurology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Prolactin (PRL) and growth hormone (GH) are closely-related hormones which regulate growth, metabolism, and reproduction in all animals. Traditionally synthesized in the pituitary gland, GH- and PRL-containing nerve cells have also been found in the central nervous system of several mammalians. GH has been identified in brain extracts from chickens and PRL- -containing neurons have been shown in the brain of Japanese quail. Since PRL may influence reproduction by a direct action on the central nervous system, and PRL causes incubation and ovarian regression in turkey hens, we have systematically mapped the location of GH- and PRL-containing neurons within important regulatory areas of the brain of female turkeys and ring doves. Both laying and incubating birds were employed to ascertain any anatomical differences in the distribution of these neurons that might be associated with reproduction. Results showed the presence of GH- and PRL- containing neurons in specific areas of the brain that influence parental behavior, food intake, autonomic nervous system function, and reproduction. No differences were found in the locations of these neurons in laying and incubating birds. This research shows that GH and PRL produced in the brain may have an important role in regulating poultry reproduction and behavior. Scientists will use this knowledge to study how this regulation occurs.

Technical Abstract: Growth hormone-(GH) and prolactin-(PRL) containing neurons and nerve fibers were identified in the hypothalamus and a few extra-hypothalamic areas of turkey and ring dove brains. In this study, we employed specific antibodies raised against turkey GH, and chicken synthetic PRL peptide. Growth hormone-immunoreactive (ir) neurons were found in hippocampus (Hp), periventricular hypothalamic nucleus (PHN), supraoptic nucleus (SON), suprachiasmatic nucleus, lateral hypothalamic nucleus(LHy), paraventricular nucleus (PVN), medial ventromedial hypothalamic nucleus, inferior hypothalamic nucleus, and infundibular hypothalamic nucleus (IN). Dense GH-ir fibers were found in the medial & lateral septal area, external zone of the median eminence (ME; turkey only), internal zone of ME (dove only), and bed nucleus of the pallial commissure (nCPa). Prolactin neurons were found in the Hp,amygdala,PVN, PHN, SON, LHy, bed n. of the stria terminalis spars magnocellularis, premammillary and lateral mammilary nucleus. The presence of GH-ir-, and PRL-ir neuronal cell bodies in several hypothalamic nuclei and GH-ir fibers occur throughout hypothalamus indicate that GH and PRL may function as a peptidergic neuromodulator. The brain locations where GH-ir or PRL-ir perikarya & fibers are found indicate that the brain GH or PRL may influence parental behavior, food intake, autonomic nervous system function and reproduction.