Changes of AVT levels in plasma, neurohypophysis and hypothalamus in relation to oviposition in the laying hen.
Arginine vasotocin (AVT) is a neurohypophysial hormone involved in the reproductive function in avian species. We measured AVT concentrations in the neurohypophysis and plasma in relation to indomethacin blocked oviposition and to prostaglandin (PG) E2-induced premature oviposition in the hen. In addition, AVT concentration in the hypothalamus was measured in relation to spontaneous oviposition. In the control group the concentration of AVT decreased in the neurohypophysis and increased in plasma at oviposition. In hens that were administrated indomethacin, oviposition was delayed for several hours and no changes in the levels of AVT in neurohypophysis and plasma were observed at the predicted time of oviposition. Premature oviposition was induced within 5 min after the administration of PGE2. The levels of AVT decreased in the neurohypophysis and increased in plasma at the PGE2-injected premature oviposition. The increases of AVT levels in paraventricular and supraoptic nuclei were observed 2 and 5 h after spontaneous oviposition. The results indicate that oviposition causes an increase in the release of AVT from neurohypophysis and suggest that the synthesis of hypothalamic AVT may be stimulated by oviposition.
Sasaki
T
T
Laboratory of Animal Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Japan.
Shimada
K
K
Saito
N
N
D000818:Animals; D001923:Brain Chemistry / Q000502:physiology; D002645:Chickens; D015232:Dinoprostone / Q000494:pharmacology; D005260:Female; D010058:Oviposition / Q000187:drug effects / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D013495:Supraoptic Nucleus / Q000187:drug effects / Q000378:metabolism*; D014668:Vasotocin / Q000097:blood*
D015232:Dinoprostone; D014668:Vasotocin