Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When Rana cancrivora were collected from fresh water and dehydrated (weight loss 4-10%) by exposure to saline, the plasma titre of hydro-osmotic activity, measured by amphibian bladder assay, was increased three-to fourfold. This activity, which was abolished by thioglycollate and by incubation with tyrosinase or trypsin, was ascribed to vasotocin. The plasma vasotocin activities (hydrated and dehydrated frogs respectively) were estimated to be 0-03-0-5 and 0-15-0-25 mug/1; if referred to oxytocin as a standard the equivalent values were 10 and 30-60 mu./ml. Assuming that the increase represented released pituitary hormone, the amount of vasotocin released by osmotic dehydration was calculated to be of the order of 1 ng. Pituitary glands of hydrated and dehydrated frogs were estimated to have 0.15 and 0-18 mug vasotocin/gland respectively. The possible physiological function of released vasotocin in promoting reabsorption of urea from the urinary bladder is discussed in relation to the euryhaline ability of R. cancrivora.
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PMID:Vasotocin-like activity in the plasms of the euryhaline frog (Rana cancrivora) after transfer from fresh water to saline. 81 47

alpha-Melanocyte-stimulating hormone (alpha-MSH) has been shown to act directly on the mammalian melanocyte in short-term cultures of hair follicles obtained from the Siberian hamster. Melanogenesis was stimulated through an increase in tyrosinase activity which resulted in an increase in melanin production. The response of hair follicle melanocytes to alpha-MSH occurred only in follicles taken from moulting animals, implying that they show a discontinuous expression of MSH receptors during the hair follicle growth cycle. Synthetic 1-24 ACTH had no effect on melanogenesis regardless of whether the follicles came from moulting or non-moulting animals. The pineal peptide, [8-arginine]-vasotocin (AVT), inhibited melanin production without a concomitant decrease in tyrosinase activity. In this respect AVT resembled melatonin, although AVT showed a potency ratio of less than half on a molar basis. The action of AVT, like that of melatonin, must ultimately be on some post-tyrosinase step in melanin biosynthesis. In these hair follicle melanocytes AVT seems to bind to specific receptors since neither of the closely related peptides, oxytocin and [8-arginine]-vasopressin, displayed any activity in our culture system.
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PMID:Effects of alpha-melanocyte-stimulating hormone and [8-arginine]-vasotocin upon melanogenesis in hair follicle melanocytes in vitro. 627 86

On incubation with a tyrosinase preparation at pH 7.5, oxytocin and vasopressin were inactivated. The loss of oxytocic activity did not differ significantly from that of milk-ejecting activity in oxytocin, nor the loss of pressor activity from that of antidiuretic activity in vasopressin. Oxytocin was inactivated less rapidly at pH 6.6 than at pH 7.5. At pH 3.9 neither oxytocin nor vasopressin was inactivated. Analogues of oxytocin and vasopressin, in which tyrosine is replaced by phenylalanine, were not inactivated by the tyrosinase preparation used. On incubation of bradykinin with two different tyrosinase preparations, there was no loss of oxytocic activity at pH 7.5 but an almost total loss at pH 3.9. In the presence of p-nitrophenol, ascorbic acid, sodium diethyldithiocarbamate and during incubation under anaerobic conditions the inactivation of oxytocin at pH 7.5 was inhibited, but not that of bradykinin at pH 3.9. It is concluded that the tyrosinase preparations used contain two distinct enzymes or activities, the one inactivating oxytocin and vasopressin at pH 7.5 and the other bradykinin at pH 3.9.
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PMID:Effect of tyrosinase preparations on oxytocin, vasopressin and bradykinin. 1386 28

Short sequence amino acids or oligopeptides represent a relatively new and promising area of dermatology. Oligopeptides are defined as peptide sequences ranging from 2 to 20 amino acids. This class of proteins includes potent biologically active compounds, which can modulate various cellular and molecular processes. The medical potential of short sequence peptides was initially characterized many decades ago with the identification of biological mediators such as angiotensin, vasopressin, oxytocin and bradykinin. However, the role of oligopeptides in affecting biological activity within the skin has only recently been explored. Currently, the dermatologic use of protein peptide fragments is a rapidly growing field of research. Recent studies suggest that treatment with various biologically active peptides can result in favourable clinical outcomes such as for the treatment of hyperpigmentation disorders with tyrosinase inhibitors and the use of collagen synthesis modulators to diminish skin laxity. In this review, we explore the roles of biologically active short sequence peptides as potential therapeutics through the modulation of collagen, elastin and melanin synthesis.
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PMID:Bioactive oligopeptides in dermatology: Part I. 2267 43