|Jmol 3D model||Interactive image|
|Molar mass||461.46 g/mol|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Morphine-6-glucuronide (M6G) is a major active metabolite of morphine, and as such is the molecule responsible for much of the pain-relieving effects of morphine and heroin - M6G is formed from morphine by the enzyme UDP-Glucuronosyltransferase-2B7 (UGT2B7). M6G can accumulate to toxic levels in kidney failure.
History of discovery
Subsequent work at St Bartholomew's Hospital, London in the 1980s, using a sensitive and specific HPLC assay, accurately defined for the first time the metabolism of morphine, and the abundance of this metabolite (along with morphine-3-glucuronide, considered an inactive metabolite).
It was postulated that kidney impairment would result in accumulation of the kidney-excreted active agent M6G, leading to potentially fatal toxicity such as respiratory depression. The frequent use of morphine in critically ill patients, and the common occurrence of kidney failure in this group implied that M6G accumulation could be a common, but previously unanticipated problem. The first studies demonstrated massive levels of M6G in 3 patients with renal failure, which resolved as kidney function returned. Accumulation of M3G and M6G also decrease with return of kidney function after kidney transplantation.
A key step in defining the importance of M6G in humans came in 1992 when the substance was artificially synthesised and administered to patients with pain, the majority of whom described pain relief.
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- Hidetoshi, Y; Oguri, K; Tsukamoto, H (1969). "Metabolism of drugs. LXII. Isolation and identification of morphine glucuronides in urine and bile of rabbits". Biochem Pharmacol. 18 (2): 279–86. doi:10.1016/0006-2952(69)90205-6. PMID 5778147.
- Osborne, R; Joel, S; Trew, D; Slevin, M (1990). "Morphine and metabolite behavior after different routes of morphine administration: demonstration of the importance of the active metabolite morphine-6-glucuronide". Clin Pharmacol Ther. 47 (1): 12–9. doi:10.1038/clpt.1990.2. PMID 2295214.
- Joel, S; Osborne, RJ; Slevin, ML (1988). "An improved method for the simultaneous determination of morphine and its principal glucuronide metabolites". J Chromatogr. 430 (2): 394–9. doi:10.1016/S0378-4347(00)83176-X. PMID 3235512.
- Renal tubular transport of morphine, morphine-6-glucuronide, and morphine-3-glucuronide in the isolated perfused rat kidney. JT Van Crugten, BC Sallustio, RL Nation and AA Somogyi. Department of Clinical and Experimental Pharmacology, University of Adelaide, Australia.
- Osborne, R; Thompson, P; Joel, S; Trew, D; Patel, N; Slevin, M (1992). "The analgesic activity of morphine-6-glucuronide". Br J Clin Pharmacol. 34 (2): 130–8. doi:10.1111/j.1365-2125.1992.tb04121.x. PMC . PMID 1419474.