Phylogeny of the Neurohypophysial Hormones

• Published in: European Journal of Biochemistry
• Main Authors: Acher, Roger, Chauvet, Jacqueline, Chauvet, Marie‐Thérèse
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1972
• Subjects: spiny dogfish; Squalus acanthias
• Online Access: http://dx.doi.org/10.1111/j.1432-1033.1972.tb01951.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1432-1033.1972.tb01951.x; https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1972.tb01951.x

Two oxytocin‐like hormones have been isolated from a cartilaginous fish, the spiny dogfish Squalus acanthias , belonging to the order Pleurotremata. They have been characterized by amino acid analysis and partial sequence determination. The chemical data suggest that the oxytocin‐like hormones are [Val 8 ]‐oxytocin (Valitocin) and [Asn 4 ]‐oxytocin (Aspartocin). The biological properties of natural products are compatible with those previously published for the synthetic analogues of oxytocin. On the other hand arginine‐vasotocin, present in very small amount, has been pharmacologically recognized. In contrast to the other classes of vertebrates, the cartilaginous fishes show a particular neurophyophysial hormone heterogeneity since the three main groups, rays, sharks and chimaeras seem to have different oxytocin‐like hormones. If four species of rays have the same active principles, only one species of shark has so far been investigated and the distribution of the two new hormones remains to be studied. It is not known whether valitocin and aspartocin are present in a single gland of Squalus acanthias or each one in a particular strain. Cartilaginous fishes have arginine‐vasotocin as other nonmammalian vertebrates but the amount in the pituitary gland is comparatively much lower; the quantity per mg of pituitary powder is roughly one thousand times weaker in marine cartilaginous fishes than in bony fishes. This decrease might be explained by the existence of an uraemic regulation of osmotic pressure in the former instead of the current ionic regulation found in the latter.