Immunochemical and Biological Properties of Horse Parathyroid Hormone

Raulais, Daniel; Desplan, Claude; Monet, Jean-Dominique; Boccard, Bertrand; Milhaud, G

doi:10.3181/00379727-167-41211

Cited by 4 publications

(3 citation statements)

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“…This hypothesis seems reasonable, since it is known that the part of the PTH molecule that shows less interspecies variation is the aminoterminal end (Potts et al 1995). In addition, equine PTH has been reported to be very similar to human PTH in the aminoterminal portion (Raulais et al 1981); therefore, heterologous antibodies should be more likely to bind the most aminoterminal part of the PTH molecule. In any case, it is well known that the activity of the PTH molecule is due to the aminoterminal sequence of the molecule (Treagear et al 1973).…”

Section: Discussionmentioning

confidence: 99%

Validation and clinical utility of a novel immunoradiometric assay exclusively for biologically active whole parathyroid hormone in the horse

Garfia

Pr³

et al. 2003

Equine Veterinary Journal

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Summary Reasons for performing study: Parathyroid hormone (PTH) plays a critical role in the regulation of mineral metabolism in mammals. Until recently, the standard method for PTH measurement has been the 2nd generation intact‐PTH (I‐PTH) assay. Current evidence indicates that the I‐PTH assay binds to the PTH molecule and to an inactive N‐terminally truncated PTH fragment that tends to accumulate in the blood of uraemic patients. Therefore, a new 3rd generation PTH assay that detects only the whole PTH molecule (W‐PTH; cyclase‐activating PTH [CAP]) has been developed. Objectives: To validate this more specific W‐PTH assay for measurement of equine PTH and evaluate its clinical utility. Methods: W‐PTH and I‐PTH were measured in plasma samples from normal horses (adults and foals) and horses with nutritional secondary hyperparathyroidism (N2HPT) and with chronic renal failure (CRF). Replicate measurements and dilutional paralellism were used for assay validation. Changes in blood ionized calcium were induced by EDTA and CaCl2 administration. Results: Performance of the W‐PTH assay (accuracy, sensitivity, specificity and ability to detect changes in PTH in response to changes in calcium) was similar to that of the I‐PTH assay. Surprisingly, the relative W‐PTH concentration in normal horses and foals was higher than the relative I‐PTH concentration. W‐PTH values remained higher than I‐PTH during acute hypo‐ and hypercalcaemia. An increase in both W‐PTH and I‐PTH concentrations was found in horses with N2HPT. In horses with CRF, W‐PTH and I‐PTH values were very low and no increase in I‐PTH was observed. Conclusions: The W‐PTH assay can be used for measurement of equine PTH. Potential relevance: The use of W‐PTH assay is likely to improve the diagnosis of mineral metabolism in horses.

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Section: Discussionmentioning

confidence: 99%

Validation and clinical utility of a novel immunoradiometric assay exclusively for biologically active whole parathyroid hormone in the horse

Garfia

Pr³

et al. 2003

Equine Veterinary Journal

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“…The characteristic effects of PTH on bone are produced by the amino-terminal portion of the hormone (1-34, 1-37, 1-38). It is reported that the human PTH fragment does not show any structural differences from the equine one 19 . The dose of hPTH (1-37) chosen for this investigation was 0.5 mg kg 21 BW, which is comparable to the dosage in humans.…”

Section: Discussionmentioning

confidence: 97%

Intermittent administration of human parathyroid fragment (hPTH 1-37) on calcium and phosphorus homeostasis and bone markers in resting horses: a preliminary study

Vervuert

Scheidt

Winkelsett

et al. 2005

Equine Comp. Exerc. Physiol.

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Parathyroid hormone (PTH) has been shown to have anabolic and catabolic effects on the skeleton, and in young racing horses the anabolic effects of PTH on bone might be of great importance in reducing the risk of skeletal injury during race training. The aim of this pilot study was to elucidate the effects of intermittent exogenous application of human parathyroid fragment (hPTH 1-37) on calcium homeostasis and bone turnover in resting horses. Five horses were used in this study. Horses were treated subcutaneously with hPTH (hPTH 1-37, 0.5 μg kg−1 BW) daily at 600 h over a period of 28 days. A foregoing control trial was conducted under the identical test protocol without hPTH application. Blood samples were taken at defined times for the control and hPTH treatment to analyze ionized Ca (Ca++, AVL), total Ca (AAS), inorganic Pi (flame photometry), intact PTH (RIA), osteocalcin (ELISA) and ICTP (carboxyterminal telopeptide of type-I collagen, RIA). Eight hours after hPTH application, blood ionized Ca++ (days 1 and 28) and plasma Pi (days 1–28) increased significantly in comparison to the control. At day 1, 8 h after hPTH application, the decrease in intact plasma PTH was more pronounced after hPTH treatment than in the control, and plasma PTH levels were higher after treatment at day 14 (16 h post-injection, P<0.05), day 18 (16 h post-injection, ns) and day 24 (0 h post-injection). There were no treatment-related differences in total plasma Ca and bone markers. Intermittent PTH administration in healthy horses affected Ca and P homeostasis as well as endogenous PTH secretion, but bone turnover was not affected during the treatment period of 28 days.

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“…125 I-human PTH and 125 I-human CT were used for assays. Cross reactivity of the carboxyterminal of human and the equine PTH was investigated and validated [18,19]. Cross reactivity between human and equine CT was also proved by radioimmunoassay [9] and immunohistochemistry [3].…”

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confidence: 99%

Serum Parathyroid Hormone and Calcitonin Levels in Racehorses with Fracture.

Chiba

Kanematsu

Murakami

et al. 2000

The Journal of Veterinary Medical Science

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. Serum parathyroid hormone (PTH) and calcitonin (CT) levels in fractured racehorses were measured by radioimmunoassay. Racehorses with fracture of large bone such as the radius, third metacarpus, third carpus, digital bone or tibia, showed normal PTH level and elevated CT level in the serum. Serum PTH level was slightly higher in racehorses with sesamoid bone fracture compared to that of healthy racehorses, but not statistically significant. Moreover, serum CT level of racehorses with sesamoid bone fracture was significantly higher than that of healthy racehorses. Racehorses with sesamoid bone fracture and large bone fracture might be in different conditions of calcium regulation.-KEY WORDS: calcitonin, fracture, parathyroid hormone, racehorse, radioimmunoassay.

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Immunochemical and Biological Properties of Horse Parathyroid Hormone

Cited by 4 publications

References 0 publications

Validation and clinical utility of a novel immunoradiometric assay exclusively for biologically active whole parathyroid hormone in the horse

Validation and clinical utility of a novel immunoradiometric assay exclusively for biologically active whole parathyroid hormone in the horse

Intermittent administration of human parathyroid fragment (hPTH 1-37) on calcium and phosphorus homeostasis and bone markers in resting horses: a preliminary study

Serum Parathyroid Hormone and Calcitonin Levels in Racehorses with Fracture.

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