| Popis: |
The neurohypophysial hormones (NHs) consist of a superfamily of nonapeptide hormones that are structurally conserved throughout vertebrates. These hormones are synthesized in neurons of the hypothalamus that project to the posterior lobe of the pituitary where they are stored and released. Most species possess two members of the superfamily that are homologous to the mammalian, arginine vasopressin (AVP) and oxytocin (OXT). In teleosts, arginine vasotocin (AVT) and isotocin (IST) replace AVP and OXT, respectively. In mammals, the NHs have distinct functions as AVP is involved with fluid homeostasis and blood pressure regulation whereas OXT is involved with reproductive physiology. In teleosts, AVT plays a role in blood pressure regulation and both AVT and IST possess some overlapping actions in the induction of spawning or parturition in various fishes. Because of these functions in teleostean reproduction, the regulation of NH gene expression by estradiol was examined in the goldfish, Carassius auratus. (Abstract shortened by UMI.) |
