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Pulsatile Peptide Secretion: Encoding of Brain Messages Regulating Endocrine and Reproductive Functions
Andrés Negro-Vilar, Michael D. Culler, Marcelo M. Valença, Toni B. Flack and Gail Wisniewski
Environmental Health Perspectives
Vol. 75 (Nov., 1987), pp. 37-43
Published by: The National Institute of Environmental Health Sciences
Stable URL: http://www.jstor.org/stable/3430574
Page Count: 7
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Neuropeptides are defined chemical messengers produced by the brain to modulate its own activity and also to regulate the function of every organ system. These neuropeptides can be viewed as coded chemical signals produced by the brain and secreted into the blood or into other fluids, such as the cerebrospinal fluid, to be transported and to act at a distant site. The signals arrive to the traget organ or sometimes to an intermediary station, such as the pituitary gland, where they are decoded, transformed into a more powerful signal, and sent again through the general circulation to reach their final target. Our work has characterized the episodic or pulsatile pattern of secretion of a number of peptide hormones produced by the brain or the pituitary gland and analyzed the brain mechanisms involved in the generation of such a pulsatile pattern of hormone secretion. Molecular biology approaches have provided information on the synthesis, processing, and secretion of these brain messengers. In addition, using computer-assisted perifusion systems, we have been able to reproduce in vitro some of the signals produced by the brain and are currently trying to decode the message carried by those signals, as well as determining the intracellular messengers involved in the signal process. The importance of the neuropeptides and of the messages carried by the pulsatile signal is underlined by experiments in which animals treated with a neurotoxin were rendered infertile. The neurotoxin affects a number of neuronal systems within the brain and destroys or impairs the activity of many peptidergic neurons in areas of the brain related to regulation of reproductive functions. This work has also established that the pulsatile hormone signals seen in normal animals are either absent or grossly impaired in the infertile animals treated with the neurotoxin. Studies of pulsatile hormone secretion are, therefore, very useful peripheral markers for the evaluation of changes in cerebral function. In addition, very valuable diagnostic and therapeutic applications can be derived from the study of pulsatility patterns of neuropeptide secretion.
Environmental Health Perspectives © 1987 The National Institute of Environmental Health Sciences