Cardiovascular & Metabolic

Angiotensin I

Angiotensin I is a ten-amino-acid link in the chain that raises blood pressure, and it is notable for doing nothing. An enzyme called renin cuts it out of a larger blood protein, a second enzyme trims two residues off the end to make angiotensin II, and no receptor of its own has ever been found for the intermediate. That inertness is exactly what makes it useful: how fast a blood sample generates angiotensin I is how laboratories measure plasma renin activity, the test used when working out whether high blood pressure has a secondary cause. The human studies on file infuse it to probe that system rather than to treat anything.

Last updated 12 August 2026

Studied forRenin-angiotensin research · ACE activity probe · Blood pressure context

Evidence on file2 human observational studies · 2 in-vitro studies · 6 citations not yet graded

Strongest sourceAssociation between renin angiotensin system and cognitive outcomes over 15 years: The Look AHEAD study. (human observational study)

Mechanism

Cleaved from angiotensinogen by renin, then converted by ACE to angiotensin II; no known receptor activity itself.

Reported effects

What sources associate with this compound. Reported categories, not outcomes we have graded — each would need its own citation and rung.

Renin-angiotensin research
ACE activity probe
Blood pressure context

Dosing on file unverified

Research: 3, 10, 30 ng/kg/min infusion; 20 ng/kg/5min incremental; 10 pmol/kg IV bolus

Carried from a source that labels it unverified, and reproduced with that label attached. A record of what is reported, not a recommendation. No citation on this page establishes it.

Literature on file 11

in vitro
Human Leukocytes Contain Angiotensin I, Angiotensin II and Angiotensin Metabolites (2009, cited 12x) graded on: radioimmunoassay of extracted human leukocytes, no comparison group — read from the abstract — “abstract review”
human observational
Association between renin angiotensin system and cognitive outcomes over 15 years: The Look AHEAD study. graded on: a secondary or post-hoc analysis — read from the indexed abstract — “secondary analysis”
review or editorial
Neurotherapeutic roles of the protective arm of the renin-angiotensin system: from inflammation to cognitive rescue. graded on: indexed as "Review" - secondary literature, not a study — “Review”
in vitro
Angiotensin I-Converting Enzyme Inhibitor Activity of Some Plants Used in Thai Indigenous Medicine. graded on: an in-vitro system — read from the indexed abstract — “in vitro”
human observational
Optimization and clinical validation of a simplified workflow for renin-angiotensin-aldosterone system hormones and adrenal steroids: Addressing pre-analytical variability and operational efficiency. graded on: an observational human design — read from the indexed abstract — “cohort”

Not graded

6 citations whose study design could not be read from the title. Left ungraded rather than guessed at.

not graded
Simultaneous UPLC-MS/MS quantification of angiotensin (I and II) and eight adrenal steroids for the assessment of plasma renin activity and secondary hypertension subtyping.
not graded
NCT06282965: A Randomized, Double-blind, Placebo Controlled Study of the Safety and Efficacy of Angiotensin (1-7) in Persons With Moderate to Severe Traumatic Brain Injury (TBI) graded on: NCT06282965 is recruiting and has posted no results - a registration, not a reported outcome — “NCT06282965”
not graded
NCT02646475: Metabolic Effects of Angiotensin-(1-7) graded on: NCT02646475 is recruiting and has posted no results - a registration, not a reported outcome — “NCT02646475”
not graded
NCT02245230: Cardiovascular Effects of Angiotensin (1-7) in Essential Hypertension graded on: NCT02245230 is terminated and has posted no results - a registration, not a reported outcome — “NCT02245230”
not graded
NCT03777215: Angiotensin-(1-7) and Energy Expenditure in Human Obesity graded on: NCT03777215 is active not recruiting and has posted no results - a registration, not a reported outcome — “NCT03777215”
not graded
NCT05301192: Angiotensin-(1-7) Cardiovascular Effects in Aging graded on: NCT05301192 is recruiting and has posted no results - a registration, not a reported outcome — “NCT05301192”

Identity

Space-filling 3D model of Angiotensin I, carbon grey, nitrogen blue, oxygen red — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

2D chemical structure of Angiotensin I — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

Molecular weight: 1296.5
Molecular formula: C62H89N17O14
CAS number: 9041-90-1
PubChem CID: 3081372
UniProt: P01019 (precursor)
InChI key: ORWYRWWVDCYOMK-HBZPZAIKSA-N
SMILES: CC[C@H](C)[C@@H](C(=O)N[C@@H](CC1=CN=CN1)C(=O)N2CCC[C@H]2C(=O)N[C@@H](CC3=CC=CC=C3)C(=O)N[C@@H](CC4=CN=CN4)C(=O)N[C@@H](CC(C)C)C(=O)O)NC(=O)[C@H](CC5=CC=C(C=C5)O)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CCCN=C(N)N)NC(=O)[C@H](CC(=O)O)N
InChI: InChI=1S/C62H89N17O14/c1-7-35(6)51(78-56(87)44(25-37-17-19-40(80)20-18-37)74-58(89)50(34(4)5)77-53(84)42(15-11-21-68-62(64)65)71-52(83)41(63)28-49(81)82)59(90)75-46(27-39-30-67-32-70-39)60(91)79-22-12-16-48(79)57(88)73-43(24-36-13-9-8-10-14-36)54(85)72-45(26-38-29-66-31-69-38)55(86)76-47(61(92)93)23-33(2)3/h8-10,13-14,17-20,29-35,41-48,50-51,80H,7,11-12,15-16,21-28,63H2,1-6H3,(H,66,69)(H,67,70)(H,71,83)(H,72,85)(H,73,88)(H,74,89)(H,75,90)(H,76,86)(H,77,84)(H,78,87)(H,81,82)(H,92,93)(H4,64,65,68)/t35-,41-,42-,43-,44-,45-,46-,47-,48-,50-,51-/m0/s1

Notes unverified prose

Human research studies; Human research IV infusions

Not on file 2

1 of the 8 fields we track hold nothing on this record, and each says why. 1 further absence is named below. A blank field is a bug; a named absence is a finding.

amino-acid sequencenothing we hold supplies it
half-lifenothing we hold supplies it

Each field links to every other record missing the same thing. The full ledger holds 765 gaps across 163 records.