A sexual dimorphism in hypothalamic arginine vasotocin (AVT) gene expression and AVT plasma levels in the Japanese quail (Coturnix coturnix japonica)in response to water deprivation

To examine a possible sexual dimorphism in the osmotic control of arginine vasotocin (AVT) release in birds, age-matched male and female Japanese quai l were subjected to water deprivation. The observed increased plasma osmola lities were accompanied by increased plasma AVT levels. Plasma mesotocin le vels did not change with water deprivation. The sensitivity of the osmotic control of AVT release as determined by the slope of the relationship betwe en plasma AVT levels and plasma osmolalities was significantly (P < 0.05) h igher in males than in females. By Northern blot analysis, levels of hypoth alamic AVT gene transcripts were increased 2.3 +/- 0.14- and 3.5 +/- 0.13-f old in water-deprived male and female Japanese quail, respectively, compare d to normally hydrated birds. Our data suggest gender-related differences i n the osmotic control of AVT release and in hypothalamic AVT gene expressio n in the Japanese quail. (C) 2000 Academic Press.