Secretin

Human secretin, synthetic human secretin (shS), ChiRhoStim (US brand); historically SecreFlo (synthetic porcine secretin, withdrawn), Secrelux (porcine secretin, Europe)

Recovery, repair & tissue

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Note on this profile. Secretin is an approved prescription diagnostic agent, given intravenously in hospital imaging and endoscopy suites. It is not a research-use or self-administered compound and has no documented community use. This page explains the hormone and the published science.

Summary

Class: Naturally occurring 27-amino-acid gut hormone (secretin/glucagon superfamily); ChiRhoStim is the synthetic copy of the human sequence
Mechanism: Released by duodenal S cells when acid arrives; tells the pancreas to pour out bicarbonate-rich fluid and the stomach to release gastrin in people with gastrinoma — the basis of its diagnostic uses
Routes studied: Intravenous bolus (all approved uses and almost all human research)
Half-life: ~45 minutes (elimination, label, 12 healthy volunteers at 0.4 µg/kg)
Storage: Lyophilised vials stored frozen at −20 °C, protected from light; reconstituted solution used immediately
Regulatory status: FDA-approved orphan diagnostic (US). Not centrally authorised in the EU; availability elsewhere is patchy †

Doses are as reported in studies or by the community — never recommendations.

1What it is

Secretin is the first hormone ever identified. In 1902 Bayliss and Starling showed that an extract from the duodenal lining made the pancreas secrete even after all nerves were cut, and coined the word "hormone" to describe the messenger. It is a 27-amino-acid peptide made by S cells in the upper small intestine. When stomach acid reaches the duodenum, secretin is released, travels through the blood and instructs the pancreas to neutralise the acid with a bicarbonate-rich juice. It also slows acid output from the stomach and acts on bile ducts.

In medicine secretin is a diagnostic tool, not a treatment. Injected intravenously it provokes a measurable pancreatic response, so doctors can collect duodenal fluid and judge whether the exocrine pancreas is failing, or watch gastrin levels to unmask a gastrin-producing tumour (gastrinoma, Zollinger–Ellison syndrome). The US product ChiRhoStim is a synthetic copy of the human sequence, approved in 2004 as an orphan drug; an earlier synthetic porcine version (SecreFlo, 2002) is no longer marketed. ChiRhoStim was on the FDA drug-shortage list for several years until manufacturing issues were resolved in 2015.

Secretin had a brief period of public attention in 1998–1999 after anecdotal reports of improvement in children with autism following a diagnostic infusion. That claim was tested in more than a dozen randomised trials and did not hold up (see below). Community/self-directed use: essentially none documented.

2How it's thought to work

Pancreatic ductal cells. secretin binds the secretin receptor (a class B G-protein-coupled receptor) and raises cAMP, driving bicarbonate and water secretion through CFTR and anion exchangers. This is why fluid volume and bicarbonate concentration after secretin are the classic measures of exocrine function.

Gastrinoma cells. in normal people secretin slightly lowers gastrin; gastrinoma tissue responds paradoxically with a sharp gastrin rise (≥120 pg/mL above is the usual positive criterion), which is the basis of the secretin stimulation test.

Stomach and gut. inhibits gastric acid and emptying; stimulates bile-duct bicarbonate secretion and pepsin release.

Brain. secretin and its receptor are expressed in the hypothalamus, cerebellum and elsewhere. Rodent work suggests roles in water balance, feeding and possibly social behaviour. This is the thread the autism hypothesis pulled on; it has not translated clinically.

Acid arriving from the stomach triggers S cells in the duodenum to release secretin, which tells the pancreas to send bicarbonate-rich fluid into the gut. The acid is neutralised, which is also what makes secretin a diagnostic probe of pancreatic function.Schematic — not to scale

3What the research shows

Diagnosis of exocrine pancreatic dysfunction

The pivotal data for ChiRhoStim were crossover comparisons in healthy volunteers and patients with chronic pancreatitis showing that synthetic human secretin produced bicarbonate and volume responses equivalent to porcine secretin, with chronic-pancreatitis patients clearly separated from controls (summarised in the FDA label; Somogyi 2000s, Pancreas). Secretin-stimulated pancreatic function testing is a reference standard, though it is labour-intensive and used mainly in specialist centres.

Gastrinoma (secretin stimulation test)

Decades of data show a gastrin rise after secretin has high sensitivity (~85–95%) for gastrinoma (Frucht 1989, Ann Intern Med; Berna 2006, Medicine). The test remains in guidelines, with the caveat that proton pump inhibitors and H2 blockers cause false positives and should be stopped beforehand where safe. [7]

Graded A/B

Secretin-enhanced MRCP and ERCP

Secretin given during MR cholangiopancreatography distends the ducts and improves visualisation of pancreatic duct anatomy, pancreas divisum and early chronic pancreatitis (Matos 1997, Radiology; Sandrasegaran 2010, AJR). During ERCP it helps locate the minor papilla. The ERCP indication is on the US label; MRCP use is common but off-label. [8]

Graded A (negative)

Autism spectrum disorder

After a 1998 case series, randomised placebo-controlled trials of single or repeated intravenous secretin were run in several hundred children. The first (Sandler 1999, NEJM, n=60, porcine secretin) found no benefit; a multicentre trial of synthetic human secretin (Owley 2001, J Am Acad Child Adolesc Psychiatry) and a later repeated-dose study (Sponheim 2002) were also negative. A Cochrane review (Williams 2012, 16 , >900 children) and an RTI/AHRQ systematic review (Krishnaswami 2011, Pediatrics) concluded there is no evidence of benefit. This is one of the clearest examples in the peptide field of an anecdote that was properly tested and failed. [3][4][5][6]

Graded C/D

Other research

Rodent studies report effects on water intake, feeding and cerebellar function; secretin receptor knockout mice show mild behavioural changes. No human therapeutic trials outside autism.

4Reported side effects and interactions

Literature-reported

In 531 patients in the US clinical programme the only reactions seen in two or more people were nausea (9), vomiting (3), flushing (2) and upset stomach (2). Rare allergic reactions have been described with porcine secretin. People with liver disease may show an exaggerated response. The label lists no contraindications.

Community-reported

none — no self-directed use is documented.

Theoretical. acute pancreatitis is a theoretical concern when stimulating a diseased pancreas; it has not been a meaningful signal in trials or in large MRCP series.

Interactions. anticholinergic drugs blunt the pancreatic response; proton pump inhibitors and H2 antagonists raise gastrin and can produce false-positive gastrinoma tests.

Markers researchers commonly monitor

Secretin is itself a diagnostic probe rather than a therapy, so the "markers" are the test readouts: No compound-specific long-term markers apply, because there is no long-term use.

Marker	Why it's watched
Duodenal fluid bicarbonate concentration and volume	peak bicarbonate below ~80 mEq/L after secretin suggests exocrine insufficiency.
Serum gastrin at baseline, 2, 5, 10, 15 and 30 minutes	the secretin stimulation test; a rise ≥120 pg/mL is the usual positive threshold.
Faecal elastase-1	the non-invasive alternative for exocrine function that secretin testing is compared against.
Serum amylase/lipase	only if abdominal pain follows the test.

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

Supplied as 16 µg or 40 µg single-dose vials, stored frozen at −20 °C and protected from light. in the clinic with 8 mL or 10 mL of sodium chloride to 2 or 4 µg/mL and used at once; unused solution is discarded. This is a hospital diagnostic — the site calculator is not relevant and no self-administered dose exists.

6Commonly studied alongside

Cholecystokinin / sincalide (the two are given together in the classic secretin–CCK pancreatic function test), gastrin (as the measured readout in gastrinoma testing), GLP-1 and GLP-2 analogues such as semaglutide and teduglutide only in the sense of belonging to the same gut-hormone family.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	FDA-approved (ChiRhoStim, human secretin, orphan diagnostic). Synthetic porcine SecreFlo no longer marketed
European Union	No centrally authorised human secretin. Porcine secretin (Secrelux) has been available through national routes in some countries, with intermittent supply †
United Kingdom	Not licensed as a marketed product; obtained as an unlicensed import for specialist testing †
Australia	Not on the ARTG; accessed via the Special Access Scheme †
South Africa	Not registered with SAHPRA †
Sport	Not listed by WADA

8Open questions

Can secretin-enhanced MRCP replace invasive pancreatic function testing for early chronic pancreatitis?
What does central secretin signalling actually do in humans, given the rodent data on feeding and water balance?
Supply: a single-manufacturer orphan diagnostic remains vulnerable to shortages.

9References

1Bayliss WM, Starling EH (1902). The mechanism of pancreatic secretion. J Physiol. PubMed · DOI
2ChiRhoClin Inc. ChiRhoStim (human secretin) for injection — US prescribing information (current label). PubMed
3Sandler AD et al. (1999). Lack of benefit of a single dose of synthetic human secretin in the treatment of autism and pervasive developmental disorder. NEJM. PubMed · DOI
4Owley T et al. (2001). Multisite, double-blind, placebo-controlled trial of porcine secretin in autism. J Am Acad Child Adolesc Psychiatry. PubMed · DOI
5Williams K, Wray JA, Wheeler DM (2012). Intravenous secretin for autism spectrum disorders (ASD). Cochrane Database Syst Rev. PubMed · DOI
6Krishnaswami S, McPheeters ML, Veenstra-VanderWeele J (2011). A systematic review of secretin for children with autism spectrum disorders. Pediatrics. PubMed · DOI
7Frucht H et al. (1989). Secretin and calcium provocative tests in the Zollinger-Ellison syndrome: a prospective study. Ann Intern Med. PubMed · DOI
8Matos C et al. (1997). Pancreatic duct: morphologic and functional evaluation with dynamic MR pancreatography after secretin stimulation. Radiology. PubMed · DOI
9Afroze S et al. (2013). The physiological roles of secretin and its receptor. Ann Transl Med. PubMed · DOI

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

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11Page history

30 Oct 2026Profile published — awaiting medical review

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