Radioimmunoassay of Secretin in Plasma

Dj, Byrnes; Jp, Marjason

doi:10.1055/s-0028-1093614

Cited by 25 publications

(5 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…). Such interference has also been recognised in immunoassays for cholecystokinin , parathyroid hormone , thyrotropic hormone , glucagon , secretin , angiotensin , growth hormone , vasoactive intestinal peptide , gonadotrophins and gonadotrophin‐releasing hormone , all of which were resolved by sample extraction. When describing their vasopressin assay, Baylis and Heath emphasised that ‘even small increases in protein concentration lower binding and therefore careful control of extract protein concentration is needed to avoid the misinterpretation that a fall in binding is due to immunoreactive vasopressin’.…”

Section: Immunoassaysmentioning

confidence: 99%

Measuring Oxytocin and Vasopressin: Bioassays, Immunoassays and Random Numbers

Leng

Sabatier

2016

J Neuroendocrinology

193

148

View full text Add to dashboard Cite

In this review, we consider the ways in which vasopressin and oxytocin have been measured since their first discovery. Two different ways of measuring oxytocin in widespread use currently give values in human plasma that differ by two orders of magnitude, and the values measured by these two methods in the same samples show no correlation. The notion that we should accept this seems absurd. Either one (or both) methods is not measuring oxytocin, or, by 'oxytocin', the scientists that use these different methods mean something very different. If these communities are to talk to each other, it is important to validate one method and invalidate the other, or else to establish exactly what each community understands by 'oxytocin'. A similar issue concerns vasopressin: again, different ways of measuring vasopressin give values in human plasma that differ by two orders of magnitude, and it appears that the same explanation for discrepant oxytocin measurements applies to discrepant vasopressin measurements. The first assays for oxytocin and vasopressin measured biological activity directly. When immunoassays were introduced, they encountered problems: high molecular weight factors in raw plasma interfered with the binding of antibodies to the hormones, leading to high and erroneous readings. When these interfering factors were removed by extraction of plasma samples, immunoassays gave measurements consistent with bioassays, with measures of turnover and with the sensitivity of target tissues to exogenous hormone. However, many recent papers use an enzyme-linked immunoassay to measure plasma levels without extracting the samples. Like the first radioimmunassays of unextracted plasma, this generates impossibly high and wholly erroneous measurements.

show abstract

Section: Immunoassaysmentioning

confidence: 99%

Measuring Oxytocin and Vasopressin: Bioassays, Immunoassays and Random Numbers

Leng

Sabatier

2016

J Neuroendocrinology

193

148

View full text Add to dashboard Cite

show abstract

“…The assays all measure increased concentrations of secretin in human plasma after intraduodenal infusion of various, often unphysiologically large amounts of acid (Boden and Chey, 1973;Bloom, 1975;Byrnes and Marjason, 1976;O'Connor et al, 1976;Rhodes et al, 1976;Hanssen and Torjesen, 1977;Schaffalitzky de Muckadell and Fahrenkrug, 1977). Intraduodenal acidification is for the moment the only well-established stimulus to secretin release (Boden et al, 1975;.…”

mentioning

confidence: 99%

Secretion pattern of secretin in man: regulation by gastric acid.

Muckadell¹,

Fahrenkrug²

1978

Gut

114

View full text Add to dashboard Cite

SUMMARY Median concentration of plasma secretin in the fasting state in 11 achlorhydria patients, 17 normal subjects, eight duodenal ulcer patients, and 11 Zollinger-Ellison patients was 0 3, 1.2, 2-5, and 5 9 pmol x 1-1, respectively. Aspiration of gastric acid in normal subjects and duodenal ulcer patients was followed by a significant lowering of the plasma secretin concentration. In normal subjects insulin-induced hypoglycaemia resulted in increased secretin levels when gastric acid was allowed to enter the duodenum, whereas no changes were observed when gastric acid was aspirated. Simultaneous measurements of intraduodenal pH and plasma secretin concentration in the fasting state and in response to a meal showed that rapid falls in intraduodenal pH were followed by short-lived increments in plasma secretin concentration. These changes in pH and in secretin levels were diminished after cimetidine. It is concluded that gastric acid in man does trigger release of secretin and that secretin is secreted intermittently both in the fasting state and in response to a meal when boluses of acid enter the duodenum.In recent years several radioimmunoassays for secretin have been presented. The assays all measure increased concentrations of secretin in human plasma after intraduodenal infusion of various, often unphysiologically large amounts of acid (Boden and Chey, 1973;Bloom, 1975;Byrnes and Marjason, 1976;O'Connor et al., 1976;Rhodes et al., 1976;Hanssen and Torjesen, 1977;Schaffalitzky de Muckadell and Fahrenkrug, 1977). Intraduodenal acidification is for the moment the only well-established stimulus to secretin release (Boden et al., 1975;. It has, however, been questioned whether the requirements for release of secretin are met in human physiology (Wormsley, 1973) and it has been difficult to demonstrate changes in secretin concentrations in plasma during physiological conditions in man (Rhodes et al., 1976; Received for publication 10 April 1978 release of the hormone is expected to be dependent on acid in the duodenum.The present study was therefore undertaken in order to examine the effect of endogenously released gastric acid on plasma secretin concentration in man. MethodsSeventeen normal subjects, eight duodenal ulcer patients, 11 unoperated patients with the ZollingerEllison syndrome, and 11 patients with achlorhydria volunteered for the study after the purpose, nature, and possible risks had been carefully explained to them.In normal subjects (median age 30 years, range 24-63 years, six females) none had any history of gastrointestinal or endocrine disease. In duodenal ulcer patients (age 33 years, range 24-66 years, three females) the diagnosis was based on the demonstration of ulcer by endoscopy and radiological examination. In Zollinger-Ellison patients (age 46 years, range 32-72 years, four females) the diagnosis was established on the basis of classical history, hypersecretion of acid, and hypergastrinaemia of extragastric origin. Achlorhydria was demonstrated by the augmented histamine test, the ...

show abstract

“…Recently, several investigators [47][48][49][50][51][52] have developed RIA's for measuring secretin. In general, secretin has proven to be a relatively good immunogen, and antisera with high antibody titers have been generated.…”

Section: Secretinmentioning

confidence: 99%

“…Several investigators [48,53,54] have been successful in attaching 12~I into the N-terminal histidine. Preparations of synthetic secretin, with a tyrosyl substituted for histidine (position 1), or phenylalanine (position 6), are now available and have provided materials that can be labeled to high specific activities [50][51][52][53][54][55][56][57]. The iodinated 6-tyrosyl derivative of secretin has been reported to have less immunoreactivity when compared to radioiodinated natural secretin [54].…”

Section: Secretinmentioning

confidence: 99%

Radioimmunoassay of gastrointestinal hormones

1979

View full text Add to dashboard Cite

Since 1968, radioimmunoassays have been developed for major gastrointestinal hormones (gastrin, cholecystokinin, secretin, and gastric inhibitory peptide) and for many substances in the gastrointestinal tract that await full hormonal status (vasoactive intestinal peptide, motilin, pancreatic polypeptide, enteroglucagon, serotonin, prostaglandins, inter alia). Although reports between laboratories on the circulating levels of gastrin and gastric inhibitory polypeptide are in relatively good agreement, wide discrepancies exist in reported values of secretin and cholecystokinin. Reports on qualitative responses of these hormones to various stimuli, however, appear to be consistent between laboratories. A review of some of the studies of radioimmunoassay techniques for gastrointestinal hormones permits analysis of some of the technical problems that can be encountered.

show abstract

Radioimmunoassay of Secretin in Plasma

Cited by 25 publications

References 10 publications

Measuring Oxytocin and Vasopressin: Bioassays, Immunoassays and Random Numbers

Measuring Oxytocin and Vasopressin: Bioassays, Immunoassays and Random Numbers

Secretion pattern of secretin in man: regulation by gastric acid.

Radioimmunoassay of gastrointestinal hormones

Contact Info

Product

Resources

About