A radioimmunoassay for the <i>Hydra</i> head activator

Bodenmüller, Heinz; Zachmann, B.

doi:10.1016/0014-5793(83)80454-2

Cited by 13 publications

(8 citation statements)

References 7 publications

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“…1 has some advantages over the classical tyrosine iodination: (i) the position of the label is chemically inert and does not lose iodine upon storage, a problem often encountered with iodotyrosine peptides; (ii) peptides containing Phe and no Tyr can be labelled with iodine without a preceding substitution of Phe by Tyr. Since the substitution of Phe by (4'4)Phe is structurally less dramatic than the substitution by (3,(5)(6)(7)(8)(9)(10)(11)(12)Tyr, the complete loss of biological activity often observed after substitution of Phe by (3,(5)(6)(7)(8)(9)(10)(11)(12)Tyr can be avoided, as has been shown for the HA.…”

Section: Discussionmentioning

confidence: 93%

“…For a RIA with tritiated tracer, a typical 450p L incubation consisted of antiserum 12/4 (7,8) at a dilution of 1: 1500 and peptide or extract, all dissolved in 40mM phosphate buffered saline (pH 7.4) containing 2.5 mg/mL bovine serum albumin, 6mg/mL sodium chloride and 1 mg/mL sodium azide. After incubation at 4" for 4-6h, 5OpL [3H]-HA (1200c.p.m.)…”

Section: Ria Proceduresmentioning

confidence: 99%

“…As sensitive detection assays for the HA, an ELISA (7) and a RIA (8) have been described Abbreviations: HA, head activator; HA-LI, head activator-like immunoreactivity; RIA, radioimrnunoassay; ELISA, enzyme-linked immunosorbent assay; AcOH, acetic acid; AcONH, , ammonium acetate; HSO,NH, , ammonium sulfate; DCC, dicyclohexylcarbodiimide; Boc, t-butyloxycarbonyl; 2,4€1,Z-, 2,4 dichlorobenzyloxycarbonyl-; TFA, trifluoroacetic acid; Bzl, benzyl.…”

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confidence: 99%

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Synthesis of new head‐activator analogues and their application for improved radioimmunoassays

Bodenmüller

Escher

Zachmann

et al. 1987

International Journal of Peptide and Protein Research

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Section: Discussionmentioning

confidence: 93%

Section: Ria Proceduresmentioning

confidence: 99%

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confidence: 99%

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Synthesis of new head‐activator analogues and their application for improved radioimmunoassays

Bodenmüller

Escher

Zachmann

et al. 1987

International Journal of Peptide and Protein Research

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“…2 shows that 8 fmol were sufficient for a 50 % competition, if the biotin-avidin system was used to increase the sensitivity of the colour reaction. This sensitivity is 10-times higher than that achieved in radioimmunoassay using tritiated 'head activator' [20] and approaching the sensitivity achieved in the biological assay, where 1 fmol of 'head activator' is required in the routine assay to stimulate bud outgrowth in hydra [5]. Since the biolocial assay is extremely laborious, this ELISA is therefore suitable to determine 'head activator' in tissue extracts where low concentrations are present.…”

Section: Selection Of Antibodies F O R Radioimmunoassay and Elisamentioning

confidence: 99%

Enzyme‐linked immunosorbent assay for the neuropeptide ‘head activator’

Schaller

Bodenmüller

Zachmann

et al. 1984

European Journal of Biochemistry

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By exposing different sites of the ‘head activator’, different sets of antibodies were designed and produced which recognised either the amino or the carboxy terminus of the free ‘head activator’, which reacted with ‘head activator’ in a tissue‐fixed conformation, or which bound to the ‘head‐activator’ sequence, if it was part of a larger precursor‐like molecule. An enzyme‐linked immunosorbent assay (ELISA) was developed to characterise the antibodies and also to assay minute amounts of ‘head activator’ or ‘head‐activator’‐like immunoreactivities in animal or tissue extracts. A competitive ELISA is described which uses biotin‐avidin for enhancement. The assay is sensitive with an antibody specific for the amino terminus in the range of 0.5–50 fmol, with an antibody specific for the carboxy terminus in the range of 20–400 fmol. The ELISA specific for the amino terminus is 10‐times more sensitive than a radio‐immunoassay with tritiated ‘head activator’ [H. Bodenmüller and B. Zachmann (1983) FEBS Lett. 159, 237–240]. Previously no radioimmunoassay existed with specificity for the carboxy terminus.

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“…Priority in the discovery of HGA in hydra, amino acid sequencing, and isolation from mammalian tissues belong to Bodenmuller and Schaller [7,14]. These investigators have also elaborated methods of HGA purification and quantitation in biological specimens [8,13]. The biological role of HGA in mammals including man is still little understood [1,4,5,10,11].…”

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Distribution of a morphogenic peptide activating the head growth of hydra in rat organs following intravascular administration of3H-labeled peptide

et al. 1994

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The organ distribution of radioactivity following intravascular bolus injection of 3H-Lyshead growth activator in rats was studied. Two minutes after injection the renal level of radioactivity exceeded the blood level 7-fold; 80% of the total activity was bound with the blood cell membranes. An analysis of chemical derivatives of the labeled peptide in the plasma by means of reverse-phase high-performance liquid chromatography revealed the presence of several groups of radioactive metabolites with different hydrophilic properties. High-performance liquid chromatography of blood extracts obtained from samples taken 0.5, 1, 1.5, 2, 31, and 60 rain after rejection showed the transformation of initially hydrophobic head growth activator into more hydrophilic fragments. The 3H-Lys-head growth activator-associated radioactivity could be reliably detected in the blood only during the first two minutes after injection. The half-period of blood-to-organ distribution of 3H-labeled head growth activator lasted less than 30 seconds.Key Words: hydra head growth activator; tissue and organ d&tribution; pharmacokinetics; metabolism Hydra morphogenic peptide, or head growth activator (HGA), which governs head pole growth and tissue differentiation in the freshwater coelenterate Hydra attenuata, represents a undecapeptide pGluPro-Pro-Gly-Gly-Ser-Lys-Val-Ile-Leu-Phe. It can also be isolated from the brain and intestine of mammals, including man. This is a unique example of a regulatory peptide which has preserved its structure during phylogenesis from the most primitive to the highly developed forms of life. Priority in the discovery of HGA in hydra, amino acid sequencing, and isolation from mammalian tissues belong to Bodenmuller and Schaller [7,14]. These investigators have also elaborated methods of HGA purification and quantitation in biological specimens [8,13]. The biological role of HGA in mammals including man is still little understood [1,4,5,10,11].The goal of the present work was to study the distribution of 3H-Lys-HGA in rat tissues after intravascular bolus administration in order to estimate the rate of its clearance from the blood and to elucidate the pathways of its elimination. MATERIALS AND METHODSThe experiments were carried out on three male Wistar rats weighing 300-350 g. The anesthetized animals (pentobarbital sodium, 30 mg/kg) were administered via the femoral artery catheter 1 ml of

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A radioimmunoassay for the Hydra head activator

Cited by 13 publications

References 7 publications

Synthesis of new head‐activator analogues and their application for improved radioimmunoassays

Synthesis of new head‐activator analogues and their application for improved radioimmunoassays

Enzyme‐linked immunosorbent assay for the neuropeptide ‘head activator’

Distribution of a morphogenic peptide activating the head growth of hydra in rat organs following intravascular administration of3H-labeled peptide

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