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Arginine Vasotocin Gene Expression and Hormone Synthesis During Ontogeny of the Chicken Embryo and the Newborn Chick
Author(s) -
Mühlbauer E.,
Hamannt D.,
Xu B.,
Ivell R.,
Udovic B.,
Ellendorff F.,
Grossmann R.
Publication year - 1993
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.1993.tb00484.x
Subject(s) - vasotocin , medicine , endocrinology , biology , embryo , gene expression , messenger rna , ontogeny , in situ hybridization , arginine , gene , neuropeptide , embryogenesis , amino acid , microbiology and biotechnology , receptor , biochemistry
Chicken embryos at different developmental stages (embryonal day (E) 6 to 21) and chicks at posthatch day 1 (D1) were monitored for the development of their hypothalamo‐neurohypophysial system as indicated by the kinetics of arginine vasotocin (AVT) gene expression via mRNA concentration and brain AVT content. Our data concerning the onset of gene expression support previous results from our laboratory and others about an early activation of the AVT gene transcriptional and translational activity around E6. We could detect measurable amounts of AVT in chicken embryo brains at E6 and an exponential increase during further development until D1. Dot blots of hypothalamic RNA extracts indicated that AVT gene transcript concentrations rose between E12 and E17 and slightly dropped thereafter. Northern hybridization showed that this drop was caused by a decrease of full length message and an increase of smaller transcripts during late embryonal and D1 stages, probably an AVT mRNA specific degradation phenomenon. The dissociation between the increase of AVT concentration and AVT mRNA concentration visible at the D1 stage might be due to accumulation and storage of AVT in the magnocellular neurons, preferentially in their axon terminals in the neurohypophysis. Blood samples taken from E14 onwards revealed a constant increase in plasma osmolality and plasma AVT concentration. Our data suggest that, in the chicken, AVT seems to be required early during embryonal development, either for osmoregulatory or further unknown functions.