Arginine vasopressin (AVP) is also known as anti-diuretic hormone (ADH). The two major effects of this peptide, that of increasing blood pressure by vasoconstriction and reducing water loss by promoting water re-absorption in the kidney, are described as its primary functions. But other effects of AVP have been demonstrated. For example, in the adult mammal AVP has a role in platelet aggregation, hepatic glycogenloysis, and memory consolidation, and the purpose of the course of study described in this thesis was to examination a putative alternative function for AVP. In certain rat myogenic cell lines introduction of vasopressin results in promotion of fusion and up-regulation of muscle specific gene expression. This effect has been described as being mediated by the V1a-vascular receptor. In addition, Data were published suggesting there was a significant amount of AVP immunoreactivity (ir-AVP) in human foetal skeletal muscle. ir-AVP was described at concentrations that could not be explained by plasma concentration, and described in relation to gestation age. Taken together these results suggest a significant role for vasopressin in skeletal muscle for development, and point to an additional alternative site for the synthesis of biologically active AVP. An extraction method was developed which employed solid phase extraction (SPE) followed by radioimmunoassay. The physical recovery of the SPE stage was reproducibly better than 70% when extracting AVP from homogenised muscle tissues. The radioimmunoassay had a cross reactivity of less than 0.01% with both oxytocin and arginine vasotocin. This extraction method was developed as a response to the demonstration that the direct assay of acidified extracts did not supply an accurate measure of the amount of vasopressin in extracted muscle. The reported ir-AVP was shown to probably be the result of acid inference in the assay. Levels of ir-AVP from foetal muscle samples extracted using SPE were not significant. This was in contrast to levels found in several positive control tissues - human foetal adrenal and pituitary glands, and rat adult adrenal glands - that were in close agreement with previously published data.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:653041 |
| Date | January 2000 |
| Creators | Johnston, Nicholas Ian Falkinder |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/22358 |
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