Losartan potassium

Losartan (potassium) is an angiotensin II receptor type 1 (AT1) antagonist, competing with the binding of angiotensin II to AT1 with an IC50 of 20 nM.

Signaling Pathways >> GPCR/G Protein >> Angiotensin Receptor

Research Areas >> Cardiovascular Disease

IC50: 20 nM (angiotensin II)

Losartan competes with the binding of angiotensin II to AT1 receptors. The concentration that inhibits 50% of the binding of angiotensin II (IC50) is 20 nM[1]. Losartan (40 μM) affects ISC but prevents the effect of ANGII on ISC[2]. Losartan significantly reduces Ang II-mediated cell proliferation in endometrial cancer cells. The combination of losartan and anti-miR-155 has a significantly greater antiproliferative effect compared to each drug alone[3].

Losartan (0.6 g/L, p.o.) -treated Fbn1C1039G/+ mice show a reduction in distal airspace caliber relative to placebo-treated Fbn1C1039G/+ animals. The doses of losartan and propranolol are titrated to achieve comparable hemodynamic effects. Analysis of pSmad2 nuclear staining reveals that losartan antagonizes TGF-β signaling in the aortic wall of Fbn1C1039G/+ mice. Losartan can improve disease manifestations in the lungs, an event that cannot plausibly relate to improved hemodynamics[4]. Losartan (10 mg/kg, intraarterial injection) increases blood angiotensin levels four- to sixfold. Losartan (10 mg/kg, i.p.) increases plasma renin levels 100-fold; plasma angiotensinogen levels decreases to 24% of control; and plasma aldosterone levels are unchanged[5].

An MTT assay is used to measure cell proliferation and viability. For the assay, 5000 cells in 200 μL media per well are seeded in a 96 well plate. After overnight incubation to allow for cell attachment, the medium is removed by suction. MTT at 1 mg/mL concentration in serum-free medium is added and then incubated for 4 h at 37°C. After removal of MTT solution, 100 μL of DMSO is added to dissolve formazan crystals. Absorbance at 570 nm and at 600 nm as a reference is then measured using a microplate reader. The difference in absorbance is thus relative to the extent of cell survival.

Female Fbn1C1039G/+ mice undergo timed matings with wild-type male mice. At 14.5d post-coitum, pregnant female Fbn1C1039G/+ mice are treated with oral losartan (0.6 g/L in drinking water; n=10), propranolol (0.5 g/L; n=6) or placebo (n=12). Therapy is continued throughout lactation and after weaning until 10 months of age. Mice are sacrificed and examined using the techniques described above. Propranolol is used for comparison with losartan because β-adrenergic receptor blockade is the current albeit controversial standard of care to modulate abnormal growth of the aortic root in MFS. Beginning at 7 weeks of age, wild-type and Fbn1C1039G/+ mice are treated with oral losartan (0.6 g/L in drinking water; n=5), propranolol (0.5 g/L; n=7) or placebo (n=10). Mice are continued on oral therapy for 6 months and then sacrificed.

[1]. Burnier, M. Angiotensin II type 1 receptor blockers. Circulation, 2001. 103(6): p. 904-12.

[2]. Ashry, O., et al. Evidence for expression and function of angiotensin II receptor type 1 in pulmonary epithelial cells. Respir Physiol Neurobiol, 2014.

[3]. Choi, C.H., et al. Angiotensin II type I receptor and miR-155 in endometrial cancers: synergistic antiproliferative effects of anti-miR-155 and losartan on endometrial cancer cells. Gynecol Oncol, 2012. 126(1): p. 124-31.

[4]. Habashi, J.P., et al. Losartan, an AT1 antagonist, prevents aortic aneurysm in a mouse model of Marfan syndrome. Science, 2006. 312(5770): p. 117-21.

[5]. Campbell, D.J., et al. Effects of losartan on angiotensin and bradykinin peptides and angiotensin-converting enzyme. J Cardiovasc Pharmacol, 1995. 26(2): p. 233-40.

Angiotensin II acetate salt | AVE 0991 | A 779 | Tranilast | PD123319 di(trifluoroacetate) | Telmisartan | Angiotensin II Receptor Ligand | Sacubitril/valsartan (LCZ696) | EMA401 | Fimasartan | (Val5)-Angiotensin II | RE 201 | C-Type Natriuretic Peptide (32-53) (human, porcine, rat) acetate salt

MOLECULAR FORMULA :

C22-H23-Cl-N6-O.K

MOLECULAR WEIGHT :

462.06

HEALTH HAZARD DATA

ACUTE TOXICITY DATA

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

2 gm/kg

TOXIC EFFECTS :

Sense Organs and Special Senses (Eye) - effect, not otherwise specified Behavioral - somnolence (general depressed activity) Gastrointestinal - hypermotility, diarrhea

REFERENCE :

KSRNAM Kiso to Rinsho. Clinical Report. (Yubunsha Co., Ltd., 1-5, Kanda Suda-Cho, Chiyoda-ku, KS Bldg., Tokyo 101, Japan) V.1- 1960- Volume(issue)/page/year: 28,3959,1994

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

200 mg/kg

TOXIC EFFECTS :

Behavioral - ataxia Lungs, Thorax, or Respiration - dyspnea Nutritional and Gross Metabolic - dehydration

REFERENCE :

KSRNAM Kiso to Rinsho. Clinical Report. (Yubunsha Co., Ltd., 1-5, Kanda Suda-Cho, Chiyoda-ku, KS Bldg., Tokyo 101, Japan) V.1- 1960- Volume(issue)/page/year: 28,3959,1994

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

1 gm/kg

TOXIC EFFECTS :

Sense Organs and Special Senses (Eye) - effect, not otherwise specified Behavioral - altered sleep time (including change in righting reflex) Behavioral - ataxia

REFERENCE :

KSRNAM Kiso to Rinsho. Clinical Report. (Yubunsha Co., Ltd., 1-5, Kanda Suda-Cho, Chiyoda-ku, KS Bldg., Tokyo 101, Japan) V.1- 1960- Volume(issue)/page/year: 28,3959,1994

TYPE OF TEST :

LDLo - Lowest published lethal dose

ROUTE OF EXPOSURE :

Intraperitoneal

SPECIES OBSERVED :

Rodent - mouse

DOSE/DURATION :

400 mg/kg

TOXIC EFFECTS :

Behavioral - tremor Lungs, Thorax, or Respiration - respiratory depression Nutritional and Gross Metabolic - dehydration

REFERENCE :

KSRNAM Kiso to Rinsho. Clinical Report. (Yubunsha Co., Ltd., 1-5, Kanda Suda-Cho, Chiyoda-ku, KS Bldg., Tokyo 101, Japan) V.1- 1960- Volume(issue)/page/year: 28,3959,1994

TYPE OF TEST :

LD - Lethal dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Mammal - dog

DOSE/DURATION :

>320 mg/kg

TOXIC EFFECTS :

Behavioral - somnolence (general depressed activity) Gastrointestinal - hypermotility, diarrhea Gastrointestinal - nausea or vomiting

REFERENCE :

KSRNAM Kiso to Rinsho. Clinical Report. (Yubunsha Co., Ltd., 1-5, Kanda Suda-Cho, Chiyoda-ku, KS Bldg., Tokyo 101, Japan) V.1- 1960- Volume(issue)/page/year: 28,3959,1994 ** OTHER MULTIPLE DOSE TOXICITY DATA **

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Rodent - rat

DOSE/DURATION :

16695 mg/kg/53W-I

TOXIC EFFECTS :

Behavioral - food intake (animal) Gastrointestinal - changes in structure or function of salivary glands Nutritional and Gross Metabolic - weight loss or decreased weight gain

REFERENCE :

KSRNAM Kiso to Rinsho. Clinical Report. (Yubunsha Co., Ltd., 1-5, Kanda Suda-Cho, Chiyoda-ku, KS Bldg., Tokyo 101, Japan) V.1- 1960- Volume(issue)/page/year: 28,4001,1994

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

SPECIES OBSERVED :

Mammal - dog

DOSE/DURATION :

2450 mg/kg/14W-I

TOXIC EFFECTS :

Gastrointestinal - changes in structure or function of salivary glands Gastrointestinal - nausea or vomiting

REFERENCE :

KSRNAM Kiso to Rinsho. Clinical Report. (Yubunsha Co., Ltd., 1-5, Kanda Suda-Cho, Chiyoda-ku, KS Bldg., Tokyo 101, Japan) V.1- 1960- Volume(issue)/page/year: 28,3969,1994 ** REPRODUCTIVE DATA **

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

763 mg/kg

SEX/DURATION :

female 15-21 day(s) after conception

TOXIC EFFECTS :

Reproductive - Effects on Newborn - growth statistics (e.g.%, reduced weight gain) Reproductive - Effects on Newborn - behavioral Reproductive - Effects on Newborn - physical

REFERENCE :

TJADAB Teratology, The International Journal of Abnormal Development. (Alan R. Liss, Inc., 41 E. 11th St., New York, NY 10003) V.1- 1968- Volume(issue)/page/year: 51,367,1995

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

2943 mg/kg

SEX/DURATION :

female 15-21 day(s) after conception lactating female 20 day(s) post-birth

TOXIC EFFECTS :

Reproductive - Effects on Newborn - viability index (e.g., # alive at day 4 per # born alive) Reproductive - Effects on Newborn - growth statistics (e.g.%, reduced weight gain) Reproductive - Effects on Newborn - behavioral

REFERENCE :

TJADAB Teratology, The International Journal of Abnormal Development. (Alan R. Liss, Inc., 41 E. 11th St., New York, NY 10003) V.1- 1968- Volume(issue)/page/year: 51,367,1995

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

2943 mg/kg

SEX/DURATION :

female 15-21 day(s) after conception lactating female 20 day(s) post-birth

TOXIC EFFECTS :

Reproductive - Maternal Effects - other effects Reproductive - Specific Developmental Abnormalities - urogenital system

REFERENCE :

TJADAB Teratology, The International Journal of Abnormal Development. (Alan R. Liss, Inc., 41 E. 11th St., New York, NY 10003) V.1- 1968- Volume(issue)/page/year: 51,367,1995

TYPE OF TEST :

TDLo - Lowest published toxic dose

ROUTE OF EXPOSURE :

Oral

DOSE :

9265 mg/kg

SEX/DURATION :

female 15 day(s) pre-mating female 0-19 day(s) after conception

TOXIC EFFECTS :

Reproductive - Effects on Newborn - viability index (e.g., # alive at day 4 per # born alive) Reproductive - Effects on Newborn - weaning or lactation index (e.g., # alive at weaning per # alive at day 4) Reproductive - Effects on Newborn - growth statistics (e.g.%, reduced weight gain)

REFERENCE :

TJADAB Teratology, The International Journal of Abnormal Development. (Alan R. Liss, Inc., 41 E. 11th St., New York, NY 10003) V.1- 1968- Volume(issue)/page/year: 51,383,1995