Guanfacine-13C,15N3is intended for us as an internal standard for the quantification of guanfacine by GC- or LC-MS. Guanfacine is an α2-adrenergic receptor (α2-AR) agonist with Kivalues of 93, 1,380, and 3,890 nM for α2A-, α2B-, and α2C-ARs, respectively, in a radioligand binding assay.1It has EC50values of 52, 288, and 602 nM for α2A-, α2B-, and α2C-ARs, respectively, for stimulated [35S]GTPγS binding. It also binds to imidazoline receptor 1 (Ki= 19 nM in a radioligand binding assay).2Guanfacine (0.3-5 mg kg) binds to adrenergic receptors in the central nervous system and lowers blood pressure in hypertensive rats in a dose-dependent manner.3It also improves spatial working memory deficits induced by hypobaric hypoxia in rats.4Formulations containing guanfacine are used in the treatment of high blood pressure and attention deficit hyperactivity disorder (ADHD). 1.Jasper, J.R., Lesnick, J.D., Chang, L.K., et al.Ligand efficacy and potency at recombinant α2 adrenergic receptors: Agonist-mediated [35S]GTPγS bindingBiochem. Pharmacol.55(7)1035-1043(1998) 2.Nikolic, K., Filipic, S., and Agbaba, D.QSAR study of imidazoline antihypertensive drugsBioorg. Med. Chem.16(15)7134-7140(2008) 3.Scholtysik, G.Pharmacology of guanfacineBr. J. Clin. Pharmacol.10(Suppl 1)21S-24S(1980) 4.Kauser, H., Sahu, S., Kumar, S., et al.Guanfacine is an effective countermeasure for hypobaric hypoxia-induced cognitive declineNeuroscience254110-119(2013)
Nitisinone-13C6is intended for use as an internal standard for the quantification of nitisinone by GC- or LC-MS. Nitisinone is an inhibitor of 4-hydroxyphenylpyruvate dioxygenase (HPPD), which converts 4-hydroxyphenylpyruvate (HPPA) to homogentisate in the tyrosine catabolic pathway.1Nitisinone increases urinary levels of HPPA and 4-hydroxyphenyllactate (HPLA) in rats when administered at a dose of 10 mg kg. Nitisinone (3 mg kg) prevents the neonatal lethality of fumarylacetoacetate hydrolase (FAH) deficiency in mice when administered to pregnant dams.2It exhibits hepatoprotective effects inFAH- -mice, such as prevention of increases in plasma levels of aspartate serine aminotransferase (AST) and conjugated bilirubin, when administration is continued following birth at a dose of 1 mg kg. Nitisinone (100 μg) decreases urinary excretion of homogentisate and increases urinary excretion of HPPA, HPLA, and 4-hydroxyphenylacetate in a mouse model of alkaptonuria induced by ethylnitrosourea.3Formulations containing nitisinone have been used in the treatment of hereditary tyrosinemia type 1 (HT-1). 1.Ellis, M.K., Whitfield, A.C., Gowans, L.A., et al.Inhibition of 4-hydroxyphenylpyruvate dioxygenase by 2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione and 2-(2-chloro-4-methanesulfonylbenzoyl)-cyclohexane-1,3-dioneToxicol. Appl. Pharmacol.133(1)12-19(1995) 2.Grompe, M., Lindstedt, S., al-Dhalimy, M., et al.Pharmacological correction of neonatal lethal hepatic dysfunction in a murine model of hereditary tyrosinaemia type INat. Genet.10(4)453-460(1995) 3.Suzuki, Y., Oda, K., Yoshikawa, Y., et al.A novel therapeutic trial of homogentisic aciduria in a murine model of alkaptonuriaJ. Hum. Genet.44(2)79-84(1999)
Nitrofurantoin-13C3is intended for use as an internal standard for the quantification of nitrofurantoin by GC- or LC-MS. Nitrofurantoin is a nitrofuran antibiotic.1In vivo, nitrofurantoin (25-100 mg kg) reducesE. colireplication and abscess formation in the renal medulla of infected rats in a dose-dependent manner. It prevents kidney and bladder infection in rats following bladder inoculation with clinical isolates ofP. mirabilis. Nitrofurantoin also prevents alkalization of urine, as well as calculi and abscess formation, in a rat model ofP. vulgarisurinary tract infection.2Formulations containing nitrofurantoin have been used to treat urinary tract infections. 1.Rocha, H., Da Silva Teles, E., and Barros, M.Site of action of nitrofurantoin in experimental urinary tract infectionAppl. Microbiol.18(4)547-549(1969) 2.Hossack, D.J.N.Proteus vulgaris urinary tract infections in rats; treatment with nitrofuran derivativesBr. J. Pharmacol. Chemother.19(2)306-312(1962)
1,2-Dioleoyl-rac-glycerol-13C3 is intended for use as an internal standard for the quantification of 1,2-dioleoyl-rac-glycerol by GC- or LC-MS. 1,2-dioleoyl-rac-glycerol is a diacylglycerol that contains oleic acid at the sn-1 and sn-2 positions. It effectively binds the C1 domain to activate conventional protein kinase C forms and serves as a substrate for diacylglycerol kinases and multisubstrate lipid kinase.1,2,3 |1. Yamaguchi, Y., Shirai, Y., Matsubara, T., et al. Phosphorylation and up-regulation of diacylglycerol kinase γ via its interaction with protein kinase Cγ. J. Biol. Chem. 281(42), 31627-31637 (2006).|2. Zhou, Q.Z., Raynor, R.L., Wood, M.G., Jr., et al. Structure-activity relationship of synthetic branched-chain distearoylglycerol (distearin) as protein kinase C activators. Biochemistry 27(19), 7361-7365 (1988).|3. Epand, R.M., Shulga, Y.V., Timmons, H.C., et al. Substrate chirality and specificity of diacylglycerol kinases and the multisubstrate lipid kinase. Biochemistry 46(49), 14225-14231 (2007).