Effects of short-term dehydration on plasma osmolality, levels of arginine vasotocin and its hypothalamic gene expression in the laying hen

N. Saito, R. Grossmann

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The neurohypophysial hormone, arginine vasotocin (AVT), plays an important role in the osmoregulation of birds. After a prolonged period of water deprivation, plasma osmolality and plasma concentration of AVT are elevated. In this study, the effects of short term dehydration were examined in laying hens by measuring plasma osmolality, plasma levels of potassium, sodium and AVT and hypothalamic concentrations of mRNA encoding AVT during 8 h of water deprivation. Plasma osmolality increased significantly after at 6 h of water deprivation. Plasma sodium levels, however, did not change. Plasma potassium concentrations gradually decreased during dehydration. Plasma AVT levels and hypothalamic AVT mRNA levels increased significantly after 8 h. The results of this study demonstrate that depriving chickens of water results first in an increase in plasma osmolality followed by increases in AVT levels in plasma and AVT mRNA levels in the hypothalamus. The data indicate that the synthesis of AVT in the magnocellular neurons in the hypothalamus is activated soon after the animals are deprived of water. This indicates that both de novo synthesized AVT as well as AVT stored in the neurohypophysis are available to meet the increasing demands for the hormone during osmotic stress.

Original languageEnglish
Pages (from-to)235-239
Number of pages5
JournalComparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Volume121
Issue number3
DOIs
Publication statusPublished - Nov 1 1998
Externally publishedYes

Keywords

  • AVT mRNA
  • Arginine vasotocin
  • Chicken
  • Dehydration
  • Neurohypophysis
  • Northern hybridization
  • Osmolality
  • Radioimmunoassay

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Molecular Biology

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