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MyDeficiencies

Metyrosine

catecholamine synthesis inhibitor (tyrosine hydroxylase inhibitor)

Also sold as Demser.

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Findings for this medication

Research about this medication, graded for how strongly each finding can be attributed to it. Nothing here describes your own levels.

Metyrosine has no classical absorption-interference or catabolic-depletion mechanism: it is well absorbed orally, minimally metabolized (small fractions convert to alpha-methyldopa, alpha-methyldopamine, methyltyramine, and alpha-methylnoradrenaline), induces or inhibits no CYP450 enzyme in any source located, and is cleared predominantly renally as unchanged drug (45 to 88 percent, most of it within the first 24 hours). No food, mineral, or vitamin interaction is documented on the regulatory label. The drug's real action is direct and intended: competitive inhibition of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine synthesis, at the enzyme's tyrosine substrate-binding site. The mechanism screen against the nine classical depletion pathways found no additional classical-nutrient signal beyond the seven required physiological categories below; reduced oral intake from sedation, nausea, or diarrhea is a real labeled possibility but was not tied to any specific nutrient in any source found, and is noted only as a monitoring consideration.

catecholamine synthesis inhibitor (tyrosine hydroxylase inhibitor) · ATC C02KB01 · also sold as Demser · reviewed 2026-09-29. This describes research about the medication. It does not say anything about your own levels or health.

How to read the evidence grades

These colours describe how strongly a finding can be attributed to the medication in the research. They are not a severity score and they say nothing about your own health.

Grades describe how strongly a finding can be attributed to Metyrosine in the research — not how common it is, how serious it would be, and not anything about you personally.

Red — Severe
Two or more independent Tier A sources, this drug in the cohort, the nutrient directly measured, consistent direction, clinically meaningful magnitude, a named mechanism, no substantial contradicting Tier A evidence.
Orange — Moderate
At least one Tier A source with this drug in the cohort showing a real but bounded deficit: an exposure window, a subgroup, low frequency, or a functional rather than circulating deficit.
Yellow — Low
Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction.
Not graded — disclosed evidence gap
Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result.Source definition: Not gradeable under the rules above because nothing has been measured. Published as a documented gap, never as reassurance that there is no effect.

The five body-system areas

Each finding is counted once, in a single area. Where a study is mentioned in a second area it is context only.

Mitochondrial Burden

Each finding below is counted once, in this area only.

Mitochondrial burden - contested, drug-specific rodent evidence on dopaminergic mitochondrial injury

Yellow — Low

See study details

Metyrosine (as alpha-methyl-p-tyrosine, AMPT) is used directly as a pharmacologic tool in rodent neurotoxicology to deplete dopamine before a mitochondrial-toxin challenge; drug-specific studies disagree on whether this protects dopaminergic neuron mitochondria; a classic study found reduced formation of dopamine-oxidation neurotoxins, while a more recent in vivo study found no protection against MPTP-induced dopaminergic neuron loss.

Full detail, limits and 3 references

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: Hasbani et al. 2005 is itself the key null finding: a direct, drug-specific (AMPT-dosed), in vivo contradiction of the protective hypothesis supported by earlier in vitro and amphetamine-challenge work. A related study, Leng, Mura, Hengerer, Feldon and Ferger, 2004, Behavioural Brain Research 154(2):375-383, DOI 10.1016/j.bbr.2004.03.004, gave AMPT to mice 9 days after MPTP specifically to unmask a persistent approximately 90% striatal dopamine depletion via reduced voluntary wheel-running, consistent with MPTP's dopaminergic lesion proceeding regardless of AMPT pretreatment, corroborating Hasbani's no-protection finding rather than the earlier methamphetamine-model results.
  • At-risk subgroups: Not applicable to humans. These are rodent neurotoxicology models using acute, supraphysiologic AMPT doses to study Parkinson's disease pathways, not evidence about ordinary human metyrosine dosing for pheochromocytoma.
  • Counter-evidence on record: Axt 1990 (protective direction) and Hasbani 2005 (no protection) are themselves in direct tension; see Key negative/null findings. This tension is the finding, not a resolved answer, and is disclosed as such.

Regulatory status

Not addressed in the DEMSER label; no mitochondrial-toxicity or mitochondrial-protection language appears.

Population evidence

Tier B, drug-specific (AMPT/metyrosine directly administered), rodent only, not human. (1) Axt, Commins, Vosmer and Seiden, 1990, rats given AMPT pretreatment before methamphetamine, Brain Research 515(1-2):269-276, PMID 2113413: AMPT "significantly decreases the frequency" with which the endogenous neurotoxins 6-hydroxydopamine and 5,6-dihydroxytryptamine were detected after methamphetamine, attributed to AMPT reducing the methamphetamine-releasable dopamine pool. (2) Hasbani, Perez, Palmiter and O'Malley, 2005, C57BL/6 mice, a single acute AMPT dose (250 mg/kg intraperitoneal) given 3 hours before MPTP to hold striatal dopamine approximately 72% reduced during toxin exposure, Journal of Neuroscience 25(41):9428-9433, PMID 16221852, DOI 10.1523/JNEUROSCI.0130-05.2005: found that "genetic or pharmacologic DA depletion did not attenuate loss of dopaminergic neurons in the SN or dopaminergic neuron terminals in the striatum," meaning no protection against MPTP's mitochondrial complex I-mediated toxicity in vivo, despite earlier in vitro work suggesting dopamine depletion should protect.

Mechanism

Named, contested. MPTP's toxic metabolite MPP+ directly inhibits mitochondrial complex I in dopaminergic neurons. The classic hypothesis, supported by in vitro pharmacology, is that reducing intraneuronal dopamine with a tyrosine hydroxylase inhibitor should reduce dopamine's own oxidative, quinone-forming contribution to that mitochondrial injury. Hasbani et al. found this did not hold in intact mice, and discuss that glial and microglial inflammatory responses, which are intact in vivo but absent from earlier in vitro systems, may dominate acute MPTP toxicity instead.

Counter-evidence held on record

This is neurotoxicology tool-compound research using acute, supraphysiologic AMPT doses in rodent Parkinson's disease models, not evidence of general mitochondrial harm or benefit in humans taking metyrosine at therapeutic doses for pheochromocytoma. No mitochondrial-support supplementation is implied in either direction.

Oxidative Stress

Each finding below is counted once, in this area only.

Oxidative stress - drug-specific rodent evidence, reverse-direction, contested by a null in vivo finding

Yellow — Low

See study details

The same AMPT-specific rodent literature bears on oxidative stress from a reverse, protective direction: two classic studies found AMPT reduces formation of oxidative dopamine-derived neurotoxins under an amphetamine challenge, though this protective direction was not replicated in a different, MPTP-based, in vivo model.

Full detail, limits and 2 references

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: Hasbani et al. 2005, disclosed above, is the direct drug-specific null finding for the MPTP-toxicity context specifically; it is the same source used as counter-evidence in the Mitochondrial burden entry (see Overlap map).
  • At-risk subgroups: Not applicable to humans on therapeutic dosing; rodent pharmacologic-challenge models only.
  • Counter-evidence on record: See Mitochondrial burden entry; the same three-study body of evidence is shared between the two categories and should not be double-counted as independent confirmation (see Overlap map).

Regulatory status

Not addressed in the label; no oxidative-stress language appears for metyrosine or its drug class.

Population evidence

Tier B, drug-specific, rodent only. Axt et al. 1990 (as above, PMID 2113413) and Wagner, Lucot, Schuster and Seiden, 1983, rats, Brain Research 270(2):285-288: "pretreatment with AMT [alpha-methyltyrosine] attenuated the long-lasting dopamine depletion induced by methamphetamine," while reserpine, a different, vesicle-depleting drug, intensified it, consistent with AMPT specifically preventing an oxidative dopamine-release process that causes lasting terminal damage. Contrasted directly with Hasbani et al. 2005 (as above, PMID 16221852), which found no protection in the MPTP mitochondrial-toxicity model.

Mechanism

Named: dopamine can auto-oxidize to reactive quinones and generate hydroxylated neurotoxins (6-hydroxydopamine, 5,6-dihydroxytryptamine) when massively released by methamphetamine; reducing the releasable dopamine pool with a tyrosine hydroxylase inhibitor reduced this specific oxidative pathway in the methamphetamine-challenge studies. The MPP+-driven MPTP model works through a different, mitochondrial complex-I-mediated route that, per Hasbani et al., does not appear to depend as heavily on dopamine's own oxidation in vivo.

Counter-evidence held on record

A reverse-direction, protective mechanistic signal in specific rodent drug-challenge paradigms, not evidence that metyrosine reduces or worsens oxidative stress in ordinary human use. No antioxidant supplementation is implied by either direction of this finding.

Copper and Iron Balance

Copper and iron are assessed separately. Nothing here is counted twice.

Iron - mechanism clarification

Yellow — Low

See study details

Tyrosine hydroxylase, the enzyme metyrosine directly and competitively inhibits, is a non-heme iron- and tetrahydrobiopterin-dependent monooxygenase; metyrosine's mechanism is competition with tyrosine at the substrate-binding site, not chelation or displacement of the enzyme's iron, so no drug-induced iron-depletion mechanism is established, despite the target enzyme's genuine iron dependency.

Full detail, limits and 1 references

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: None found. No metyrosine-specific iron study exists in any channel reached to confirm or refute a systemic effect, which is exactly why this entry is written as a mechanism clarification rather than a graded deficiency claim.
  • At-risk subgroups: None identified. This entry addresses the biochemistry of the drug's target enzyme, not any human population's iron status.
  • Counter-evidence on record: None needed; no iron-depletion claim is being made here (see framing caution).

Regulatory status

The DEMSER label describes the mechanism only as inhibition of tyrosine hydroxylase; it does not use iron- or cofactor-specific terminology.

Population evidence

Tier B, established pharmacology/biochemistry reference, not metyrosine-specific outcome data. A crystal structure study (Goodwill et al., "Crystal structure of tyrosine hydroxylase with bound cofactor analogue and iron at 2.3 A resolution," Biochemistry, 1998, PMID 9753429) resolved bound iron in tyrosine hydroxylase's active site; this primary paper could not be opened directly this session (PubMed bot-verification block on every attempt) and is cited as a named background reference, not independently read in full. Corroborating background confirmed via a ScienceDirect Topics overview page on tyrosine hydroxylase, opened and read this session, which states the enzyme "requires ferrous iron as cofactors," that "Fe2+ is bound directly to TH, and is oxidized to Fe3+ by O2," describes it as "a monooxygenase that contains iron without the heme group," names tetrahydrobiopterin (BH4) as the second required cofactor, and separately confirms in the same source that "the activity of TH is inhibited by the compound alpha-methyl-p-tyrosine."

Mechanism

Named and specific: metyrosine is a structural analog of tyrosine that competes with the natural substrate at tyrosine hydroxylase's tyrosine-binding site. This is substrate-site competition, not cofactor antagonism; of the Step 2 mechanism classes, "direct enzyme inhibition" is present, but no evidence was found that metyrosine antagonizes, chelates, or displaces the enzyme's iron itself. No study located measured systemic iron, ferritin, or hepcidin in metyrosine-treated patients or animals, in either direction.

Counter-evidence held on record

Per Hard Rule 2, this entry exists to correctly attribute the pathway's iron dependency to the specific enzyme metyrosine targets (tyrosine hydroxylase), and to distinguish it from the copper-dependent step one enzyme downstream (dopamine beta-hydroxylase, see the separately graded Copper entry below). It is not an iron-depletion finding, and no iron supplementation is implied by metyrosine use.

Copper

Not graded — disclosed evidence gap

See study details

No biological evidence, at any tier, and no circulating consumer claim, was found linking metyrosine to copper status in either direction. The pathway's genuinely copper-dependent enzyme, dopamine beta-hydroxylase, sits one step downstream of metyrosine's actual target and is not itself inhibited by the drug.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. ungraded

Limits on what this shows

  • Why no grade: Both conditions for UNGRADED are met. (1) No Tier A, B, or independently verified Tier C evidence connects metyrosine to copper or ceruloplasmin status. The only copper-relevant biochemistry located concerns dopamine beta-hydroxylase (DBH), a separate, downstream enzyme: confirmed via Wikipedia's "Dopamine beta-hydroxylase" article, opened and read this session, describing DBH as "a copper-containing oxygenase" whose reaction uses "dopamine, vitamin C (ascorbate), and O2" and that converts dopamine to norepinephrine. Metyrosine's competitive inhibition acts entirely upstream, at tyrosine hydroxylase's substrate site (see Iron entry above); no source located describes metyrosine as binding, inhibiting, or otherwise interacting with DBH or its copper cofactor. (2) No consumer or practitioner claim about metyrosine and copper was located to rebut as white.

Search channels tried

Wikipedia and ScienceDirect Topics overview pages for tyrosine hydroxylase and dopamine beta-hydroxylase, both opened successfully: background enzymology confirmed, no drug-to-copper connection found. Crossref works-search API, three phrasings attempted ("metyrosine copper," "metyrosine copper dopamine beta hydroxylase," "alpha-methyl-p-tyrosine dopamine beta hydroxylase copper"): the first returned HTTP 429 before any results loaded, the third also returned HTTP 429 with an explicit instruction not to retry that endpoint further this session; neither is treated as a confirmed zero, this is disclosed as a tooling limitation, not a completed null search. PubMed direct search-listing and article pages were blocked by a bot-verification challenge on every attempt made this session, across every topic, not specific to copper. Europe PMC's REST API returned a proxy instruction not to retry after an earlier 429 on a different query. OpenAlex's works-search endpoint returned HTTP 429 on both attempts made this session. WebSearch, including a direct phrase search for a consumer "nutrient depletion checker" style claim, returned no metyrosine-specific copper claim before the session's WebSearch budget (200 of 200 calls) was exhausted. Net result: the verified enzymology (Tier B, but explaining an absence of mechanism rather than supporting one) consistently rules out a plausible direct pathway from metyrosine to copper, and no channel that did return content surfaced any metyrosine-copper connection in either direction; the copper-specific Crossref queries remain a genuine tooling gap rather than a confirmed absence, disclosed here so a later revision knows to re-run them.

Gut Microbiome Risk

Each finding below is counted once, in this area only.

Gut microbiome risk

Not graded — disclosed evidence gap

See study details

No biological evidence, at any tier, and no circulating consumer claim, was found linking metyrosine to gut microbiome composition, diversity, or function.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. ungraded

Limits on what this shows

  • Why no grade: Both conditions for UNGRADED are met: (1) no mechanism from the Step 2 screen (absorption interference, bile acid effects, antibacterial activity, altered transit time) plausibly applies to metyrosine's chemistry or its labeled pharmacokinetics, and no direct or class-level study was located; (2) no consumer or practitioner claim about metyrosine and the gut microbiome was located to rebut as white.

Search channels tried

Crossref works-search API, "alpha-methyl-p-tyrosine gut microbiome," succeeded and returned no metyrosine-specific results: only an unrelated Parkinson's-disease alpha-synuclein/gut-microbiome book chapter and an unrelated phenylketonuria infant-gut-microbiome paper, neither naming metyrosine, confirmed as a genuine zero for this drug. PubMed direct pages were blocked by a bot-verification challenge on every attempt. Europe PMC and OpenAlex works-search were unavailable (429, and an explicit instruction not to retry Europe PMC further this session). The Semantic Scholar API returned HTTP 429 on its one attempt. WebSearch, before its session budget was exhausted, surfaced no consumer claim connecting metyrosine to gut or microbiome effects.

Oxygen and ATP Output

Oxygen delivery and ATP production are assessed separately. Nothing here is counted twice.

Oxygen delivery/utilization - rare labeled hematologic adverse effects, undefined mechanism

Orange — Moderate

See study details

The regulatory label lists anemia among rare adverse hematologic effects of metyrosine, alongside eosinophilia, thrombocytopenia, and thrombocytosis, with no established mechanism and no quantified incidence.

Full detail and limits

What the grade means here: At least one Tier A source with this drug in the cohort showing a real but bounded deficit: an exposure window, a subgroup, low frequency, or a functional rather than circulating deficit. orange

Limits on what this shows

  • Key negative/null findings: None located. No independent case series or pharmacovigilance study quantifying metyrosine-associated anemia, eosinophilia, thrombocytopenia, or thrombocytosis was found in any channel reached this session; PubMed's direct pages were blocked by a bot-verification challenge on every attempt targeting this topic, so a dedicated literature search beyond the label and its monograph restatement could not be completed.
  • At-risk subgroups: Not defined in any source located.
  • Counter-evidence on record: None found. The absence of independent quantification is itself the main limiting factor on this entry, not a documented null result.

Regulatory status

DailyMed DEMSER label, adverse reactions section, lists "adverse hematologic effects (including eosinophilia, anemia, thrombocytopenia, and thrombocytosis)" as occurring rarely. No percentage, denominator, or study population size is given. Independently corroborated on the Drugs.com clinical monograph, which draws on the same underlying label text.

Population evidence

Tier A, drug-in-cohort (regulatory label reporting from clinical use of metyrosine in pheochromocytoma patients), but unquantified and without a defined sample size or comparator. This bounds the entry at orange under the low-frequency criterion rather than red.

Mechanism

Not established in the label or in any source located this session. No hemolysis, marrow-suppression, or nutrient-mediated mechanism is named for metyrosine specifically.

Counter-evidence held on record

Anemia, eosinophilia, thrombocytopenia, and thrombocytosis are rare labeled clinical outcomes, not evidence of iron, vitamin B12, copper, or other nutrient deficiency, per Hard Rule 2. Any hematologic change on metyrosine should prompt clinical evaluation by a prescriber, not an assumption of a nutrient effect or self-directed supplementation.

ATP production

Not graded — disclosed evidence gap

See study details

No biological evidence, at any tier, and no circulating consumer claim, was found linking metyrosine to ATP synthesis or cellular energy output. Labeled sedation and fatigue-adjacent CNS effects are clinical symptom outcomes, not measured energy-metabolism findings, and are not used to support a grade here.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. ungraded

Limits on what this shows

  • Why no grade: Both conditions for UNGRADED are met: (1) no Tier A, B, or independently verified Tier C evidence connects metyrosine to ATP production or mitochondrial energy output; (2) no consumer claim (for example a generic "low energy" claim tied specifically to metyrosine) was located to rebut as white. Sedation is a labeled adverse reaction occurring in "almost all patients," but per Hard Rule 2 this is a clinical symptom outcome of reduced central catecholamine tone, not a measured ATP or energy-metabolism finding, and is not used to support a grade here.

Search channels tried

Crossref works-search API, "metyrosine ATP adenosine triphosphate," succeeded and returned only generic, unrelated ATP-biochemistry reference entries (an AccessScience encyclopedia entry, a homeopathic materia medica chapter, a Meyler's Side Effects of Drugs chapter on ATP itself, and an unrelated wastewater-treatment engineering dissertation), none naming metyrosine, confirmed as a genuine zero for this drug. PubMed direct pages were blocked by a bot-verification challenge on every attempt. Europe PMC, OpenAlex, and Semantic Scholar were unavailable (429 on every attempt reached). WebSearch, before its session budget was exhausted, found no consumer "low energy" or ATP-specific claim tied to metyrosine.

All references used above
  1. DEMSER (metyrosine) capsules, prescribing information — DailyMed, Bausch Health US LLC, SetID 32fb2f2f-34b5-4cd5-9145-c3ab37c5ca92. Opened directly; sections reviewed: mechanism of action, pharmacokinetics, drug interactions, warnings and precautions, adverse reactions, hepatic/renal impairment, pregnancy and pediatric use, dosing.
  2. DrugBank, Metyrosine (DB00765) — Opened directly to confirm ATC code (C02KB01), brand name, drug class, and mechanism of action.
  3. Drugs.com, Metyrosine clinical monograph for professionals — Opened directly; used to corroborate the label's adverse-reactions detail, including the hematologic effects list (eosinophilia, anemia, thrombocytopenia, thrombocytosis) and drug-interaction detail (phenothiazines, butyrophenones, CNS depressants, urinary catecholamine assay interference).
  4. Wikipedia, "alpha-Methyl-p-tyrosine" (AMPT / metirosine) — Opened directly via two access points (the AMPT and Metirosine article titles, same underlying content); used for pharmacokinetic detail (peak plasma levels, half-life, urinary recovery, dosing effects on catecholamine reduction), research/off-label use context, and adverse-effect detail. Explicitly confirms no oxidative stress, mitochondrial, iron, or copper content in this source.
  5. ScienceDirect Topics, "Tyrosine Hydroxylase" overview — Opened directly; used to confirm tyrosine hydroxylase's non-heme iron and tetrahydrobiopterin (BH4) cofactor requirements, and to independently confirm alpha-methyl-p-tyrosine as its inhibitor.
  6. ScienceDirect Topics, "alpha methyl p tyrosine" overview — Opened directly; used for mechanism and research-use context. Explicitly confirms no oxidative stress, mitochondrial, iron, or copper content in this source.
  7. Wikipedia, "Dopamine beta-hydroxylase" — Opened directly; used to confirm dopamine beta-hydroxylase's copper-containing oxygenase status and its use of ascorbate (vitamin C) as a cofactor, and its role converting dopamine to norepinephrine one step downstream of tyrosine hydroxylase.
  8. Goodwill KE, Sabatier C, Marks C, Raag R, Fitzpatrick PF, Stevens RC. Crystal structure of tyrosine hydroxylase with bound cofactor analogue and iron at 2.3 A resolution: self-hydroxylation of Phe300 and the pterin-binding site. — Biochemistry, 1998. Structural study resolving bound iron in the tyrosine hydroxylase active site. PMID 9753429.Direct PubMed article page returned a bot-verification challenge on every attempt this session; not independently opened in full. Cited as a named background reference, corroborated via the ScienceDirect Topics tyrosine hydroxylase overview (above), which was independently opened and read.
  9. Levine JH, role of ascorbic acid in dopamine beta-hydroxylation (title-level citation). — A PubMed-indexed paper on ascorbic acid as the endogenous cofactor and electron donor for dopamine beta-hydroxylase cofactor regeneration. PMID 3097015.Direct PubMed article page returned a bot-verification challenge; not opened. Listed at title level only, from the original WebSearch results list; the ascorbate/copper cofactor facts used in this dossier are instead drawn from and cited to the independently opened Wikipedia dopamine beta-hydroxylase article above.
  10. Sjoerdsma A, Engelman K, Spector S, Udenfriend S. Inhibition of catecholamine synthesis in man with alpha-methyl-tyrosine, an inhibitor of tyrosine hydroxylase. — The Lancet, 1965. The first human pharmacology study of metyrosine (as alpha-methyl-tyrosine), drug in cohort. DOI 10.1016/s0140-6736(65)90062-0.Bibliographic metadata (title, authors, journal, year, DOI) confirmed via Crossref; full text not opened this session.
  11. Axt KJ, Commins DL, Vosmer G, Seiden LS. alpha-Methyl-p-tyrosine pretreatment partially prevents methamphetamine-induced endogenous neurotoxin formation. — Brain Research, 1990, 515(1-2):269-276. Rat study, AMPT directly administered. PMID 2113413.Abstract-level content opened via the ScienceDirect article page; full text behind a subscription paywall, not accessed.
  12. Wagner GC, Lucot JB, Schuster CR, Seiden LS. Alpha-methyltyrosine attenuates and reserpine increases methamphetamine-induced neuronal changes. — Brain Research, 1983, 270(2):285-288. Rat study, alpha-methyltyrosine directly administered.Abstract-level content opened via the ScienceDirect article page; full text behind a subscription paywall, not accessed.
  13. Hasbani DM, Perez FA, Palmiter RD, O'Malley KL. Dopamine depletion does not protect against acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in vivo. — Journal of Neuroscience, 2005, 25(41):9428-9433. C57BL/6 mice, single acute AMPT dose (250 mg/kg i.p.) directly administered. PMID 16221852, DOI 10.1523/JNEUROSCI.0130-05.2005.
  14. Leng A, Mura A, Hengerer B, Feldon J, Ferger B. Effects of blocking the dopamine biosynthesis and of neurotoxic dopamine depletion with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on voluntary wheel running in mice. — Behavioural Brain Research, 2004, 154(2):375-383. Mouse study, AMPT directly administered post-MPTP. DOI 10.1016/j.bbr.2004.03.004.Abstract-level content opened via the ScienceDirect article page; full text behind a subscription paywall, not accessed.
  15. Crossref works-search API queries (multiple, this session) — Used directly, not through a secondary aggregator, to search for metyrosine- or alpha-methyl-p-tyrosine-specific results against oxidative stress, iron, mitochondria, gut microbiome, and ATP/adenosine triphosphate search terms. Five of seven attempted queries returned genuine, checked results confirming zero metyrosine-specific hits for those terms (only unrelated pharmacopeial standards, background biochemistry, or unrelated-disease results were returned); two later queries adding copper-specific terms were rate-limited (HTTP 429) and are disclosed as a tooling gap in the Copper entry rather than treated as a confirmed null.