Vasotocin

Vasopressin 8-arginine-vasopressin (AVP) Antidiuretic hormone (ADH) Lysipressin Oxytocin (OT) 8-leucine-vasotocin... 

Oxytocin, Lysin- und Arginin-Vasoprcssin, Arginin-Vasotocin. Adrenocorticotrope Hormone (Corticotropine, ACTH)... 

Oxytocin, a nine amino acid peptide, is synthesized primarily in the paraventricular and supraoptic (SON) nuclei of the hypothalamus, from which it is released to the general circulation through the posterior pituitary (Insel et ah, 1997). However, oxytocinergic fibers have also been found to project from the PVN to the limbic system and several autonomic centers in the brain stem. This central OT pool appears to be independent of pituitary OT release cerebrospinal fluid (CSF) and plasma OT responses to numerous stimuli are not correlated (Insel, 1997). Oxytocin and its analog (or partner) peptide vasopressin are found only in mammals. A related peptide, vasotocin, thought to be the evolutionary precedent of these peptides, is found in reptiles and birds. The first known actions of OT were its peripheral effects on the physiology of new mothers. In mammals, OT stimulates milk ejection and uterine contraction, essential aspects of maternal physiology (Insel et ah, 1997). 

Hormones related to oxytocin and vasopressin occur in most vertebrates, the compound vasotocin shown in Fig. 30-4 being the most common. Substitution of phenylalanine for isoleucine at position 3 gives arginine vasopressin, the vasopressin found in our bodies. Structure of oxytocin and related hormones82 are also shown in Fig. 30-4. Like somatostatin, vasopressin and oxytocin may also form antiparallel pleated sheet structures with P turns. The structural requirements for hormone activity have been studied intensively. Both the macrocyclic hexapeptide ring and the tripeptide side chains are necessary for maximal activity.83... 

Figure 30-4 Structure of the nonmammalian hormone vasotocin and of related hormones including ocytocin and vasopressin.

Table 5.31. 13C Chemical Shifts (<5C in ppm) of Oxytocin, Arginine Vasotocin, Arginine, and Lysine Vasopressin in D20 [833],...

C Atom Oxytocin Arginine vasotocin Arginine vasopressin Lysine vasopressin... 

Oxytocin is a nine-amino-acid peptide composed of a six-amino-acid disulfide ring and a three-membered tail (Figure 37-2). Oxytocin and vasopressin differ from vasotocin—the only posterior... 

Leucine enkephalin vasotocin dipeptides Open-tubular Mass spectrometry 14... 

The inhibitory GTP binding protein (G ) which has been demonstrated in many different cell types is also present in Leydig cells. Evidence for this was obtained from studies with cultured Leydig cells in which it was shown that the inhibitory effects of arginine vasotocin on steroidogenesis could be abolished by pertussis toxin, which inactivates Gj via ADP ribosylation [9]. However, effects of LH with or without vasotocin were not reported. Similar studies with forskolin [10] demonstrated that low concentrations of this compound inhibited hCG-stimulated cyclic AMP production and this inhibition was prevented by pertussis toxin. Recently, direct evidence for the presence of Gj in rat Leydig cells has been obtained by the demonstration of a 41000 protein (aj) after [32P]ADP ribosylation [11]. 

These data show the presence in subesophageal and thoracic ganglia of Locusta of an antiparallel dimeric peptide (F2), which was called the AVP-like insect diuretic hormone (AVP-like DH) (H). The sequence homology between the AVP-like DH and the vertebrate neurohypophyseal peptides is strong Cys-(2)-(3)-(4)-Asn-Cys-Pro-(8)-Gly-NH2. The AVP-like DH and AVP differ only at positions 2, 3, and 4, whereas the homology to the ancestral molecule arginine vasotocin is even stronger, with differences restricted to positions 2 and... 

Bernard K, Bogliolo S, Ehrenfeld J (2005) Vasotocin and vasopressin stimulation of the chloride secretion in the human bronchial epithelial cell line, 16HBE14o-. Br J Pharmacol 144(8) 1037-1050... 

Various other substances have been shown to act as inhibitors of pituitary gonadotropic activity. These include synthetic arginine vasotocin (M13) and an extract prepared from the pineal gland of cattle (R14). 

M13. Moszkowska, A., and Ebels, I., A study of the antigonadotrophic action of synthetic arginine vasotocin. Experientia 24, 610-611 (1968). 

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