Radioimmunoassay and Plasma Levels of Endothelin, a Vasoconstrictor of Potential Importance in Renal Disease

Hartter, Engelbert; Schiessler, Rudolf; Petzl, D. H.; Schuller, Wolfgang; Kargl, R; Woloszczuk, W.

doi:10.1159/000418772

Cited by 5 publications

(2 citation statements)

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“…Endothelin was determined by a highly sensitive radioimmunoassay using the Hartter and coworkers method (Hartter et al, 1990). Extraction of endothelin from plasma was done by absorption onto prewashed SepPak C 18 cartridges (Waters/Millipore, Watford, Hertsforshire, England) by slow passage of 5 ml plasma samples in 50 jil acetonitrile by a vacuum manifold (Univac, UniEquip, Martinsried, Germany).…”

Section: Assaysmentioning

confidence: 99%

Clinical evidence for a neuromodulator action of endothelin in the hypothalamic-pituitary-adrenal axis in man

Haak

Jungmann²,

Haak³

et al. 2009

Exp Clin Endocrinol Diabetes

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In order to investigate whether the ubiquitous signalling peptide endothelin might also act as a neuromodulator in the stimulation of the hypothalamic-pituitary-adrenal axis, 15 patients (4 female, 11 male, aged 35-67 years) with hypopituitarism were investigated and the results were compared to those of 8 healthy male volunteers (aged 24-31 years). Patients and controls received double-blind in random order either 0.1 IE per kg body weight regular insulin (insulin induced hypoglycemia) or 1 ml 0.9% sodium chloride (placebo) on 2 separate days. Control subjects only received on an additional day 0.1 IE per kg body weight regular insulin plus glucose 10% (euglycemic hyperinsulinemic glucose clamp). In control subjects hypoglycemia resulted in a significant increase in adrenocorticotropin (ACTH) and cortisol which was preceded by an increase in circulating endothelin levels (p < 0.01 vs placebo and euglycemic clamp) while endothelin, ACTH and cortisol remained unchanged both after placebo and in the euglycemic hyperinsulinemic clamp. In contrast, patients with hypopituitarism showed neither changes in circulating endothelin levels nor a stimulation of the hypothalamic-pituitary-adrenal axis during insulin-induced hypoglycemia. These data demonstrate that 1) endothelin levels are enhanced by metabolic stress 2) the responsiveness of endothelin levels to metabolic stress is linked to the presence of an intact pituitary gland and 3) endothelin might be involved in the stimulation of the hypothalamic-pituitary-adrenal axis.

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Section: Assaysmentioning

confidence: 99%

Clinical evidence for a neuromodulator action of endothelin in the hypothalamic-pituitary-adrenal axis in man

Haak

Jungmann²,

Haak³

et al. 2009

Exp Clin Endocrinol Diabetes

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“…Extraction with methanol (MeOH) [20]. Si-CI8 cartridgcs werc conditioned with 2 ml of MeOH followed by 3 ml of water.…”

Section: Extraction Proceduresmentioning

confidence: 99%

Determination of endothelin-1 immunoreactivity in plasma, cerebrospinal fluid and urine

Rolinski¹,

Sadri²,

Bogner³

et al. 1994

Res. Exp. Med.

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Abstract. Endothelin-! (ET-! ) is a potent vasoconstrictor peptide apparently invo]ved in a number of vascular diseases in man. Nonetheless, its determination in biological sampies is difficult, and data on plasma or urine concentrations are controversiaL We investigatcd different satnple preparation procedures as weIl as different radioimmunoassays for lheir inf)uence on ET-l measurement. Recovery of ET-I depended on Ihe extraction procedure, the type and size 01' the extraction columns and on the biulugical matrix itself. Incomplete removaJ of matrix components by the extraclion leads to the formation of particulate maUer in the evaporated eluate. When dissolved in assay buffer, ET-I was found to be absorbed to and only partly released from these partieul ates, so that it was not accessible for measurement in a radioimmunoassay. This was lhe ease for all extraction procedures investigated except for that in volving aeetie acid. HPLC analysis of spiked sam pies revealed that ET-I is in part degraded during extraction, most probably to Meth-sulphoxide ET-l. Dilution curves of synthetic pure ET-l standards from different suppliers. prepared either in plasma with subsequent extraction ur in assay buffer of the rcspcctive radioimmunoassay, resulted in considcrable differences in the measurcd values for ET-l-immunoreactivity. Every radioimmunoassay tcsted had a specific pallem of rccognizing different synthetic ET-I standards. In condusiol1, the measurement of ET-l-immunoreactivity is strongly influenced by the experimental conditions of samplc prcparation as weil as by the radioimmunoassay employed.

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Transgenic rats expressing the human ET-2 gene: a model for the study of endothelin actions in vivo

et al. 1999

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Previous studies have characterized the endothelin peptides (ET-1, ET-2, ET-3) as strong vasoconstrictors which are possibly involved in the pathogenesis of cardiovascular disease. Whereas ET-1 and ET-3 have been characterized using a number of approaches, little is known about the function of ET-2. The aim of this study was to define the role of ET-2 in physiology and pathophysiology using a transgenic approach. Transgenic rats expressing a genomic construct of the human ET-2 gene were generated by microinjection of fertilized oocytes from Sprague-Dawley rats. Two transgenic lines were generated, and one line was further characterized in detail. Studies on mRNA expression demonstrated that the transgene is expressed predominantly in kidney, gastrointestinal tract, adrenal gland, lung, and brain. Plasma endothelin levels were elevated 2-fold, and big-endothelin levels were elevated 2.5-fold. Despite these alterations blood pressure in transgenic rats remained normal. Further analysis of transgenic animals revealed that endothelin receptors were not downregulated, and that infusion of exogenous human ET-2 results in an enhanced blood pressure response. These observations suggest the presence of counterregulatory mechanisms influencing the effects of endothelin on blood pressure. One of these mechanisms may involve the nitric oxide system since infusion of an inhibitor of nitric oxide synthase resulted in a greater blood pressure response than in non-transgenic littermates. Despite unchanged blood pressure, alterations were observed in organ development and function, namely of hearts and kidneys, indicating an interference between transgene expression and growth processes. Male rats seem to be more susceptible to endothelin actions. These data show that the elevation in endothelin-2 expression in this transgenic model does not induce hypertension but leads to changes at the end-organ level. Normotension is most likely due to compensatory mechanisms such as increased nitric oxide formation.

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Radioimmunoassay and Plasma Levels of Endothelin, a Vasoconstrictor of Potential Importance in Renal Disease

Cited by 5 publications

References 0 publications

Clinical evidence for a neuromodulator action of endothelin in the hypothalamic-pituitary-adrenal axis in man

Clinical evidence for a neuromodulator action of endothelin in the hypothalamic-pituitary-adrenal axis in man

Determination of endothelin-1 immunoreactivity in plasma, cerebrospinal fluid and urine

Transgenic rats expressing the human ET-2 gene: a model for the study of endothelin actions in vivo

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