Vasopressin/Oxytocin

Vasopressin/Oxytocin. Figure 1 Amino acid sequence of AVP and OT. The disulphide bridge between Cys 1 and Cys 6 is shown. 

Many hormones and other blood-borne substances (including drugs) also alter contractile activity of smooth muscle. Some of the more important substances include epinephrine norepinephrine angiotensin II vasopressin oxytocin and histamine. Locally produced substances that may alter contraction in the tissue in which they are synthesized include nitric oxide prostaglandins leukotrienes carbon dioxide and hydrogen ion. 

Most probably some fraction of the peptides appearing in urine represents small quantities of peptide hormones, such as vasopressin, oxytocin, glucagon, and the melanocyte-stimulating hormone, the occurrence of which in small amounts in normal urine has been occasionally reported. As the specific enzymatic decomposition of these hormones takes place... 

Gonadal hormones Estrogens Progestins Androgens Neurosteroids Thyroid hormones Melatonin Vasopressin Oxytocin... 

While an organism responds to stress, a whole range of hormones is released, e.g., corticotrophin, vasopressin, oxytocin, prolactin, and thyroid hormone including... 

Vincent du Vignaud (USA, Nobel Prize, Chemistry, 1955, synthesis of Vasopressin Oxytocin)... 

Sofroniew MV, Weindl A, Schrell LF, Wetzstein R (1981) Immunohistochemistry of vasopressin, oxytocin and neurophysin in the hypothedamus and extrahypothalamic regions of the humtin and primate brain. Acta Histochem S24 79-95... 

AVP), except in the pig which has a Lys residue (iysine vasopressin). Oxytocin differs from vasopressin in having leucine at position 8 and isoleucine at position 3. Vasopressin and oxytocin analogues with some degree of receptor subtype selectivity that have been synthesized have ANTIDIURETIC or vasoconstrictor or OXYTOCIC (uterine-contracting) activity. See VASOPRESSIN RECEPTOR AGONISTS VASOPRESSIN RECEPTOR ANTAGONISTS. 

Similarly, a three-dimensional model of the vasopressin/oxytocin receptor has been defined and the binding mode of the neuropeptides has been analysed (Figure 3 and 5). Residues likely to contribute to the affinity, efficacy and selectivity have been proposed from the model. These qualitative predictions have subsequently been confirmed by site directed mutagenesis [20-22]. A number of general comments can be made ... 

Barberis C, Mouillac B, Durroux T. Structural bases of vasopressin/oxytocin receptor function. J Endocrinol 1998 156 223-229. 

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