What Is Urodilatin? Definition and What Research Reports
Urodilatin is a natriuretic peptide first identified in human urine and described in the literature as a kidney-derived relative of atrial natriuretic peptide (ANP). In peptide research the term appears in three ways: as an endogenous renal hormone, as a system studied in body-fluid and sodium physiology, and as a recombinant or synthetic peptide used in laboratory work. Published papers have examined its role in body fluid regulation, its renal actions in healthy subjects, its relationship to renal dopamine metabolism, and methods for producing it in bacteria.
Definition
Urodilatin is a peptide hormone of the natriuretic peptide family that was originally isolated from human urine and is described in the nephrology literature as a kidney-derived counterpart of atrial natriuretic peptide (ANP). It shares the core ring structure of ANP but carries a short N-terminal extension, which is why review articles have devoted attention to telling the two apart in renal tissue and urine; a 2006 review in European Journal of Medical Research framed exactly that question as "ANP and urodilatin: who is who in the kidney" (PMID 17107879). In practical terms, when a paper says "urodilatin," it is referring to this specific renal natriuretic peptide rather than to ANP, brain natriuretic peptide (BNP) or C-type natriuretic peptide (CNP).
What Class of Molecule It Is
Urodilatin belongs to the natriuretic peptide family — a group of small, disulfide-cyclised regulatory peptides rather than steroids, antibodies or small-molecule drugs. Because it derives from the same precursor family as ANP, the literature often treats "ANP-like immunoreactivity" in kidney samples as a measurement problem: assays raised against ANP may also detect urodilatin, and the 2006 review discussed how the two peptides have been distinguished in renal studies (PMID 17107879).
Reviews have also used the broader phrase the renal urodilatin system to describe the peptide together with its production site, its handling along the nephron and its proposed physiological role; a 2001 review in Cardiovascular Research used that framing when it surveyed the clinical implications of the system (PMID 11476735).
Where It Comes From
Two origins matter for readers of the literature:
- Endogenous (biological) source. Urodilatin is described as a renal natriuretic peptide, and a 2001 review in Seminars in Nephrology examined its involvement in body fluid regulation — that is, the physiology of sodium and water handling rather than cardiac hormone secretion (PMID 11320487).
- Laboratory-produced peptide. Human urodilatin has also been made recombinantly. A 2008 paper in Applied Microbiology and Biotechnology reported the expression and purification of human urodilatin using a small ubiquitin-related modifier (SUMO) fusion strategy in Escherichia coli (PMID 18189135). That kind of methods paper explains why a peptide with a natural urinary origin can nonetheless be obtained in gram-scale research quantities.
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Try it freeHow the Term Is Used in Peptide Research
The word appears in several distinct contexts, and conflating them is a common source of confusion.
| Usage | What it refers to | Example in the literature |
|---|---|---|
| Endogenous hormone | The natriuretic peptide measured in urine or renal tissue | Body fluid regulation review (PMID 11320487) |
| Physiological "system" | The peptide plus its renal production, targets and signalling | Clinical implications review (PMID 11476735) |
| Experimental agent in human physiology studies | Peptide administered under controlled conditions to probe renal responses | Study in healthy subjects with pharmacological blockade (PMID 17852806) |
| Recombinant product | Peptide expressed and purified for laboratory work | SUMO fusion expression in E. coli (PMID 18189135) |
| Analytical target | The peptide as something an assay must separate from ANP | "Who is who in the kidney" review (PMID 17107879) |
A synthetic form of urodilatin has also been studied under the name ularitide; readers scanning literature databases will encounter both terms pointing back to the same peptide sequence. Because the verified papers summarised on this page do not cover that clinical programme, no efficacy or safety statements about it are made here.
What the Published Literature Reports
The papers verified for this entry are mostly physiology reviews and mechanistic studies rather than outcome trials, so the reported findings are descriptive.
Body fluid and sodium regulation
A 2001 review in Seminars in Nephrology examined the involvement of the renal natriuretic peptide urodilatin in body fluid regulation, positioning it as a renal rather than purely cardiac participant in volume homeostasis (PMID 11320487). A companion review in Cardiovascular Research the same year discussed the clinical implications that researchers had drawn from work on the renal urodilatin system (PMID 11476735).
Renal effects in healthy volunteers
A study published in the Scandinavian Journal of Clinical and Laboratory Investigation examined renal effects of urodilatin in healthy subjects and reported that those effects were independent of blockade of the cyclooxygenase pathway and of the angiotensin II receptor (PMID 17852806). The design question there was mechanistic: whether prostaglandin- or angiotensin-dependent pathways were required for the renal response observed by the researchers.
Interaction with renal dopamine
A 2013 paper in the Journal of Nephrology reported that urodilatin regulates renal dopamine metabolism, linking the peptide to another intrarenal natriuretic signalling system (PMID 23661592). Work of this kind is typically cited when authors argue that urodilatin does not act in isolation but within a network of local renal regulators.
Identity and measurement
Finally, the 2006 European Journal of Medical Research review addressed the attribution problem directly, comparing ANP and urodilatin as candidates for renal natriuretic peptide activity (PMID 17107879). This matters when reading older literature, where "renal ANP" and "urodilatin" were not always cleanly separated.
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The verified papers summarised here are physiology reviews, a mechanistic human renal study and a recombinant-protein methods paper; none of them is a tolerability or safety trial, and no adverse-event rates, dosing schedules or infusion protocols are reproduced on this page because the verified sources do not support such figures. The human study cited above was framed around renal responses under pharmacological blockade in healthy subjects rather than around safety endpoints (PMID 17852806). Absence of reported adverse events in this small set of papers is not evidence that none exist; it reflects the scope of the literature selected for a definitional entry.
Regulatory and Research Status
Urodilatin is not marketed as an approved drug product for general use in the United States, and peptide material supplied for laboratory work is customarily labelled research use only (RUO), meaning it is not intended for human or veterinary administration. Papers describing recombinant production, such as the SUMO fusion approach reported in Applied Microbiology and Biotechnology, are written for laboratory-scale supply of research-grade peptide (PMID 18189135).
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- Most of the verified literature consists of reviews, which summarise other work rather than generate new data.
- The human study identified here involved healthy subjects under experimental blockade conditions (PMID 17852806), so findings do not automatically transfer to populations with kidney or cardiac disease.
- Mechanistic findings such as the reported regulation of renal dopamine metabolism (PMID 23661592) describe biochemical relationships, not clinical outcomes.
- Assay overlap between ANP and urodilatin has been an explicit topic of discussion in the field (PMID 17107879), which is worth keeping in mind when comparing older measurements.
This page is for educational purposes only and is not medical advice; consult a licensed physician about any medical question or decision. Nothing here describes or endorses personal use of any peptide.
References
- Urodilatin regulates renal dopamine metabolism (Journal of Nephrology, 2013)
- ANP and urodilatin: who is who in the kidney (European Journal of Medical Research, 2006)
- Expression and purification of human urodilatin by small ubiquitin-related modifier fusion in Escherichia coli (Applied Microbiology and Biotechnology, 2008)
- Renal effects of urodilatin in healthy subjects are independent of blockade of the cyclooxygenase and angiotensin II receptor (Scandinavian Journal of Clinical and Laboratory Investigation, 2008)
- The renal urodilatin system: clinical implications (Cardiovascular Research, 2001)
- Involvement of the renal natriuretic peptide urodilatin in body fluid regulation (Seminars in Nephrology, 2001)
Frequently asked questions
Is urodilatin the same peptide as ANP?▾
No. Urodilatin is a distinct natriuretic peptide of the same family, and the literature has treated separating the two as a genuine analytical question — a 2006 review was titled "ANP and urodilatin: who is who in the kidney" (PMID 17107879). Older papers sometimes reported "ANP-like" renal immunoreactivity that could reflect either peptide, so terminology in the field should be read carefully.
What does urodilatin do according to published research?▾
Reviews have described urodilatin as a renal natriuretic peptide involved in body fluid regulation (PMID 11320487), and a 2001 review discussed the clinical implications drawn from the renal urodilatin system (PMID 11476735). A 2013 study reported that urodilatin regulates renal dopamine metabolism (PMID 23661592). These are physiological descriptions, not statements about treatment outcomes.
Where in the body is urodilatin found?▾
It was originally identified in human urine and is described in nephrology literature as a kidney-associated natriuretic peptide rather than a cardiac one; a review examined its involvement in body fluid regulation from that renal perspective (PMID 11320487). Because assays can cross-detect ANP, researchers have discussed how renal peptide measurements are attributed (PMID 17107879).
How is urodilatin produced for laboratory research?▾
A 2008 paper in Applied Microbiology and Biotechnology reported expression and purification of human urodilatin using a small ubiquitin-related modifier (SUMO) fusion system in Escherichia coli (PMID 18189135). That approach is a recombinant production method for research-grade peptide; the paper addresses protein expression and purification rather than any human application.
What did the healthy-volunteer study report?▾
A study in the Scandinavian Journal of Clinical and Laboratory Investigation examined renal effects of urodilatin in healthy subjects and reported that those effects were independent of blockade of the cyclooxygenase pathway and of the angiotensin II receptor (PMID 17852806). The study was mechanistic, testing whether prostaglandin- or angiotensin-dependent signalling was required for the renal response.
Is urodilatin an approved medicine?▾
Urodilatin is not marketed as an approved drug product for general use in the United States, and peptide material for laboratory work is customarily labelled research use only. The verified literature cited here consists of renal physiology reviews, a mechanistic human study and a recombinant production paper (PMID 18189135), not regulatory approval documents.
Do the cited papers report side effects?▾
No. The verified sources are reviews and mechanistic studies, and none is a tolerability trial; the healthy-subject study was structured around renal responses under pharmacological blockade rather than safety endpoints (PMID 17852806). Absence of adverse-event data in this small set of papers should not be read as evidence that none exist.
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References
This page summarises published research for education — it is not medical advice, and nothing here is a recommendation to use, purchase, or dose any substance. Study parameters described are what researchers reported, not instructions. Consult a qualified clinician before any health decision.