![An investigation of a new phosphaturic bioassay of parathyroid hormone in the rat için kapak resmi An investigation of a new phosphaturic bioassay of parathyroid hormone in the rat için kapak resmi](/client/assets/d79c3e4af2b6d196/ctx/images/no_image.png)
An investigation of a new phosphaturic bioassay of parathyroid hormone in the rat
Başlık:
An investigation of a new phosphaturic bioassay of parathyroid hormone in the rat
Yazar:
Studzinska-Tribedi, Krystyna Zofia, author.
ISBN:
9780438052437
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (144 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: N. G. Waten.
Özet:
There has been a need for a simple, rapid and accurate assay of the parathyroid hormone (PTH) for its routine estimation in biological fluids, A bioassay based on the phosphaturic effect of PTH in the rat was therefore tested. Since complete parathyroidectomy is not easy to achieve, but is necessary for a more sensitive response to PTH, it was proposed to obtain suppression of secretion of endogenous hormone in the rat by continuous intravenous infusion of a calcium salt through the tail vein. The suppression of the hormone was assessed by a diminished phosphate excretion in the urine. The minimal output of phosphate took place during the third and fourth hours after the staxt of the infusion with calcium, but considerable fluctuations of this basal level were still present. In response to the PTH administered intravenously through the infusing system at the second hour, the phosphate excretion increased reaching a maximal value within two hours. The experimental conditions were varied in an effort to determine the lowest and most uniform excretion of phosphate, and at the same time the most sensitive response to the FTH, Investigations were thus made of the effects of increasing the concentration of the calcium lactate from 0.6 g/100 ml to 1,2 g/100 ml, the addition of glucose to the infusion fluid, and the use of anaesthetics to sedate the rats while they were being put into the apparatus. Although the excretion of phosphate was to some extent influenced by varying these conditions, the response to the PTH, when calculated as an increase above the corresponding control values, was not significantly affected. Prom preliminary experiments carried out on human serum from patients suffering from disorders of parathyroid function, there appeared to be a correlation between the results of the bioassay and the clinical findings in the patients. However, attempts to estimate crude phenol extracts of human urine for parathyroid activity were not successful, A significant correlation was foimd between the logarithm of the phosphate excretion response and the logarithm of the dose of the PTH, Commercially available parathyroid extract from Eli Lilly & Company, and highly purified preparations obtained from Organon (Holland) were used. In the most sensitive assay, carried out in the spring, this relationship was evident for values of Lilly's extract equivalent to 0.5 - 3.0 U.S.P, units. The index of precision (lambda) of this assay was 0.49. However, the sensitivity was much less when estimated in the autumn, suggesting a seasonal trend in the response. It is concluded that infusion of calcium diminishes excretion of phosphate in the rat and that the intravenous administration of PTH causes phosphaturia, which is related to the dose of hormone given. For an accurate assay must be less than 0.3. Thus this assay (lambda = 0.49) is not sufficiently reliable and so it offers no advantage over the assays involving surgical parathyroidectomy.
Notlar:
School code: 0547
Tüzel Kişi Ek Girişi:
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684389.1) | 684389-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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