On the metabolism of tritium-labelled Δ1-tetrahydrocannabinol in the rabbit

Agurell, Stig; Nilsson, Inger; Ohlsson, A; Sandberg, F

doi:10.1016/0006-2952(70)90048-1

Cited by 112 publications

(27 citation statements)

References 4 publications

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“…10,18,19 THC rapidly penetrates highly vascularized tissues resulting in a rapid decrease in plasma concentration. 20 However, intensive accumulation occurs in less vascularized tissues and finally in body fat, [21][22][23] which represents the major long-term storage site, resulting in concentration ratios between fat and plasma of up to 10 4 :1. 24 The exact composition of the material accumulated in fat is still unknown; a substantial proportion seems to consist of fatty acid conjugates of 11-OH-THC.…”

Section: Distributionmentioning

confidence: 99%

Review of Biologic Matrices (Urine, Blood, Hair) as Indicators of Recent or Ongoing Cannabis Use

Mußhoff¹,

Madea²

2006

Therapeutic Drug Monitoring

218

151

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Especially for cannabinoids, analytical procedures for the verification of recent use and generally for the assessment of the extent of drug abuse are of interest in clinical and forensic toxicology. For confirmation of abstinence, urine analysis seems to be a useful tool. Serial monitoring of THC-COOH to creatinine ratios can differentiate between recent drug use and residual THC-COOH excretion (THC-COOH/creatinine ratio Z0.5 compared with previous specimen ratio). For an assessment of the extent of cannabis use, the determination of free and bound THC-COOH and especially of THC and 11-OH-THC glucuronides are suggested as useful but need further confirmation. Blood analysis is preferred for the interpretation of acute effects after cannabis abuse. The cannabis influence factor (CIF) was demonstrated as a better tool to interpret the concentrations of THC and its metabolites in blood in forensic cases and therefore it was proposed to assume absolute driving inability because of cannabis intoxication from a CIF Z10. Additionally, a higher CIF is indicative of a recent cannabis abuse. Also discrimination between occasional use of cannabis and regular drug consumption is possible by analysis of THC-COOH in blood samples because of the long plasma half-life of THC-COOH and its accumulation in the blood of frequent cannabis consumers. In routine tests, blood samples have to be taken within a prescribed 8-day-period, and a THC-COOH concentration >75 ng/mL is assumed to be associated with regular consumption of cannabis products, whereas plasma THC-COOH concentrations <5 ng/mL are associated with occasional consumption. In contrast to other illicit drugs, hair analysis lacks the sensitivity to act as a detector for cannabinoids. THC and especially the main metabolite THC-COOH have a very low incorporation rate into hair and THC is not highly bound to melanin, resulting in much lower concentrations in hair compared with other drugs. Additionally, THC is present in cannabis smoke and also can be incorporated into the hair only by contamination. For the determination of the main metabolite THC-COOH in the picogram or femtogram per milligram range, which indicates an active consumption, special analytical procedures, such as GC/MS/MS techniques, are required.

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Section: Distributionmentioning

confidence: 99%

Review of Biologic Matrices (Urine, Blood, Hair) as Indicators of Recent or Ongoing Cannabis Use

Mußhoff¹,

Madea²

2006

Therapeutic Drug Monitoring

218

151

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“…The rather complete metabo lism of THC in man has been abundantly shown to occur in rabbits and rats [6,7]. A number of metabolites of both A9-and A8-ThHC have been identified, particularly the 11-hydroxy and 7-hydroxy metabolites of the respective isomers of THC [8,10].…”

Section: Discussionmentioning

confidence: 99%

Cannabinoids in the Urine of Man After Single and Subchronic Oral Doses of Marihuana

Sl¹,

Le²,

Moore³

et al. 1972

Int Pharmacopsychiatry

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“…The preferential storage of THC in neutral fat is a long reported experimental fact (Agurell et al 1970;Garrett, 1979;Harvey, 1984;Kreuz and Axelrod, 1973;Nahas et al, 1981). Kreuz and Axelrod using C 14 THC reported that less than 1% of the administered dose penetrates into the brain of the rat.…”

Section: The Pharmacokinetics Of Thc Its Storage In Fat and Brainmentioning

confidence: 97%

The pharmacokinetics of THC in fat and brain: resulting functional responses to marihuana smoking

Nahas

2001

Human Psychopharmacology

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A pleasant sensory perception (PSP), the high of THC or of marihuana consumption, is a consistent functional response to this drug only manifested by man, and which occurs concurrently with an increased heart rate. However, it has not been possible to relate consistently magnitude and duration of these functional markers to THC plasma concentration, whatever the route of administration. A re-analysis of all the available clinical and experimental data reporting the pharmacokinetics and storage of THC in tissues in function of time, have indicated that the discrepancies between functional responses and plasma molecular THC concentration may be accounted for by the pharmacokinetics of THC. The instant uptake and unlimited storage of THC by neutral fat limits the molecular concentration of the drug present in the plasma to a level which does not exceed 6 x 10(14) molecules/ml. The physicochemical nature of the membrane lipid bilayer (of the blood-brain barrier) will restrict the access of THC into the bilayer receptors and its: reactive enzymes. The PSP and increased heart rate of marihuana is correlated with the molecular concentration of THC in the bilayer (blood-brain barrier) of the order of 10(12)-10(14) molecules/ml. This number in turn would be related to the number of functional THC receptor sites in the lipid bilayer. THC would exert its functional properties on PSP and heart rate through a molecular transmission to specific receptor site and bilipid layer physicochemical interations. Rapid uptake and slow release of THC in fat associated with a rate-limited uptake into brain may be a general philogenetic mechanism which would protect brain function from prolonged exposure to xenobiotics like THC and other fat soluble drugs. Copyright 2001 John Wiley & Sons, Ltd.

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On the metabolism of tritium-labelled Δ1-tetrahydrocannabinol in the rabbit

Cited by 112 publications

References 4 publications

Review of Biologic Matrices (Urine, Blood, Hair) as Indicators of Recent or Ongoing Cannabis Use

Review of Biologic Matrices (Urine, Blood, Hair) as Indicators of Recent or Ongoing Cannabis Use

Cannabinoids in the Urine of Man After Single and Subchronic Oral Doses of Marihuana

The pharmacokinetics of THC in fat and brain: resulting functional responses to marihuana smoking

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