The metabolism of¹⁴C-labelled trimethylamine and itsN-oxide in man

Abstract

The metabolism and elimination of 14C-labelled trimethylamine and its N-oxide (100 mg orally) were studied in three male volunteers. For both compounds the urine was the major route of elimination, with 95% of the administered 14C being voided in the first 24 h. No radioactivity was found in expired air. The majority (greater than 95%) of the urinary 14C from both compounds was excreted as trimethylamine N-oxide.

Detection of food intake in a marine mammal using marine osmolytes and their analogues as dietary biomarkers

“…1 h and decreased monoexponentially with an approximate half-life of 2 to 3 h (Smith et al 1994, Nnane & Damani 2001. In studies with radioactively labelled TMAO, 95% of an oral dose was excreted from the body within 24 h in rats (Mitchell et al 1997) and humans (Al-Waiz et al 1987b). In humans, the maximum rate of excretion of TMAO occurs at 3 to 6 h after administration (Al-Waiz et al 1987b).…”

“…In mammals, TMAO and AsB ingested with food are absorbed rapidly and completely (Vahter et al 1983, Al-Waiz et al 1987b and are excreted unchanged via urine (Vahter et al 1983, Al-Waiz et al 1987b, Brown et al 1990, Svensson et al 1994, Vahter 1994, Mitchell et al 1997, Yoshida et al 1998, with no demonstrable retention of TMAO in body tissues (Norris & Benoit 1945, Smith et al 1994. TMAO ingested with food is absorbed as trimethylamine from the intestinal tract after reduction by gut bacteria and re-oxidised by the liver to TMAO (Al-Waiz et al 1987a).…”

Serum Trimethylamine-N-Oxide is Elevated in CKD and Correlates with Coronary Atherosclerosis Burden

“…12 Under normal physiologic conditions, circulating TMAO is rapidly cleared from the bloodstream, almost exclusively by urinary excretion. 13,14 To date, there are very few published reports on TMAO metabolism in patients with CKD, [15][16][17] and the association between TMAO concentrations and atherosclerosis burden in this group has not been investigated. Given that TMAO clearance is largely dependent on the renal excretion of this compound, and that prior studies have demonstrated TMAO to induce atherosclerotic plaque formation in rodents, we postulated that TMAO concentrations would be elevated in patients with CKD and be associated with the accelerated atherosclerosis observed in this population.…”

Capital Expenditure and Income (Foraging) during Pinniped Lactation: The Example of the Weddell Seal (Leptonychotes weddellii)

“…On the basis of studies in Weddell seals, we have identifi ed two suitable compounds, arsenobetaine (AsB) and trimethylamine N-oxide (TMAO) (Eisert, 2003;Eisert et al, 2005). Both are specifi c to, and apparently ubiquitous in, marine prey yet are neither stored nor synthesized by higher vertebrates and in mammals are eliminated rapidly from the circulation following ingestion (Edmonds and Francesconi, 1977Yancey et al, 1982;Vahter et al, 1983;Al-Waiz et al, 1987Van Waarde, 1988;Cullen and Reimer, 1989;Brown et al, 1990;Shibata et al, 1992;Smith et al, 1994;Svensson et al, 1994;Zhang et al, 1999;Lehmann et al, 2001). The biomarker method provides information on recent food intake within a timescale of hours to days, in contrast to fatty acid signatures or stable isotopes in fl uids or tissue samples, which integrate food intake over a period of months (Iverson et al, 1997a(Iverson et al, , 1997bBrown et al, 1999).…”