Vasopressins structure

Valium, see Diazepam van der Waals forces, alkanes and. 92 polymers and, 1215 Vancomycin, structure of, 351 van t Hoff, Jacobus Hendricus, 7 Vasopressin, structure of, 1029 Vegetable oil, 1061... 

Figure 4.40. Vasopressin and Synthetic Vasopressin. Structural formulas of (A) vasopressin, a peptide hormone that stimulates water resorption, and (B) l-desamino-8-d-arginine vasopressin, a more stable synthetic analog of this antidiuretic hormone.

FIGURE 4.40 Vasopressin and synthetic vasopressin. Structural formulas of... 

These include nicotinic acetylcholine receptors, neuronal calcium channels, muscle sodium channels, vasopressin receptors, and iV-methyl-D-aspartate (NMDA) receptors. Some general features of the structure, function, and evolution of biologically active peptides isolated from Conus venom are presented. 

The primary structures of the pituitary hormones vasopressin and oxytocin differ by Just two amino acids, ... 

The first non-peptide oxytocin antagonists, based on a spiropiperidine template, were described by Merck in 1992 [68-70]. The binding affinity data for key compounds from this series are summarised in Table 7.2. The initial screening hit, L-342,643, (23), had modest (4/iM) affinity for rat uterine oxytocin receptors and very little vasopressin selectivity [71]. A structure activity relationship (SAR) study was carried out around this template, focussing on the toluenesulphonamide group. This work led to the identification of bulky lipophilic substitution as key to improved oxytocin potency, while the introduction of a carboxylic acid group led to improved... 

Pericytes lie periendothelially on the abluminal side of the microvessels (Figure 15.3). A layer of basement membrane separates the pericytes from the endothelial cells and the astrocyte foot processes. Pericytes send out cell processes which penetrate the basement membrane and cover around 20-30% of the micro-vascular circumference [18]. Pericyte cytoplasmic projections encircling the endothelial cells provide both a vasodynamic capacity and structural support to the microvasculature. They bear receptors for vasoactive mediators such as catecholamines, endothelin-1, VIP, vasopressin and angiotensin II. Pericytes become mark-... 

Schulz, A., Grosse, R., Schultz, G., Gudermann, T., and Schoneberg, T. (2000) structural implication for receptor oligomerization from functional reconstitution studies of mutant V2 vasopressin receptors. J. Biol. Chem. 275, 2381-2389. 

A vast number of hormones and neurotransmitters are synthesized from simple structural units including chains of amino acids. Among the amino acid based hormones are comparatively large protein molecules such as prolactin, growth hormone and insulin, and shorter chains of amino acids which may form peptide hormones, such as oxytocin and vasopressin. Protein based hormones are essential for metabolism, growth and some components of reproduction. However, evidence for specific influences of these compounds on human behavior is limited. 

Desmopressin Desmopressin, 8-D-arginine vasopressin-l-(3-mercaptopropionic acid) (24.4.6), is a structural analog of vasopressin. It is synthesized by a multi-step synthesis by methods specific to peptide chemistry, and its synthesis will not be examined here [71-74],... 

Table I. Intra-Residue Energies of Phenylalanine in Vasopressin Minimum Energy Structures and in minimum energy conformations of Ac-Phe-NMe.

The time given is that of the molecular dynamics conformation which was minimized to give the minimum energy structure of vasopressin. The energy of the Phe fragment was calculated for these structures. 

Vasopressin occurs in two variations arginine-vasopressin (AVP) and lysine-vasopressin (LVP), in which Arg is replaced by Lys. The conformation of these hormones is almost identical to that of oxytocin, except that the terminal tail is con-formationally free and not held by the ring. The physiological role of the vasopressins is the regulation of water reabsorption in the renal tubules (i.e., an antidiuretic action). In high doses, they promote the contraction of arterioles and capillaries and an increase in blood pressure hence the name of these hormones. Because of their very similar structures, OT and VP overlap in a number of effects. 

Ox ocin is a nonapeptide which is structurally related to vasopressin. It stimulates rhythmic uterine contractions and is widely used by intravenous infusion of a diluted solution to induce labour and to treat postpartum bleeding. In large doses, it may cause relaxation of vascular smooth muscle causing hypotension in patients with cardiac disease or who are dehydrated. It has water-retaining properties and when given for prolonged periods to patients whose intake is electrolyte-free it causes overhydration and hyponatraemia. This may result in convulsions in the newborn with the risk of cerebral damage. 

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