Vasopeptidase inhibitor omapatrilat induces profound insulin sensitization and increases myocardial glucose uptake in Zucker fatty rats: Studies comparing a vasopeptidase inhibitor, angiotensin-converting enzyme inhibitor, and angiotensin II type I receptor blocker.
BACKGROUND
ACE inhibitors (ACEIs) improve insulin resistance and prevent type 2 diabetes, possibly mediated by inhibition of bradykinin (BK) degradation. The vasopeptidase inhibitor omapatrilat (OMA) raises BK to a greater extent than ACEIs by dual enzyme inhibition, whereas its insulin-sensitizing effects and mechanisms have not been investigated.


RESULTS
We compared the insulin-sensitizing effects of OMA, ramipril (an ACEI), losartan (an angiotensin II type 1 receptor blocker), and placebo by 2-step euglycemic hyperinsulinemic clamp in insulin-resistant Zucker fatty rats (n=6 to 7 in each group). OMA resulted in a lower rate of endogenous glucose production than placebo at baseline (35+/-5 versus 54+/-4 mmol x kg(-1) x min(-1), P<0.01), greater suppression of endogenous glucose production by low-dose insulin (73+/-11% versus 27+/-18%, P<0.05), and greater glucose disposal at high-dose insulin (135+/-5 versus 92+/-4 mmol x kg(-1) x min(-1), P<0.01). Ramipril tended to improve insulin sensitivity, but losartan did not. OMA significantly increased 2-deoxyglucose uptake by myocardium, fat, and skeletal muscle. Ramipril increased 2-deoxyglucose uptake only by some skeletal muscles, but losartan did not. The insulin-sensitizing effects of OMA were blocked significantly by HOE-140 (a BK, B2 receptor antagonist) and NG-nitro-L-arginine methyl ester (a nitric oxide synthase inhibitor) in all tissues except myocardium.


CONCLUSIONS
OMA induces profound insulin sensitization and increases myocardial glucose uptake in Zucker fatty rats. This effect is greater than that of ramipril and probably occurs at least in part via stimulation of the B2 receptor. OMA has the potential for greater type 2 diabetes prevention than ACEI.
Wang
Chao-Hung
CH
Department of Medicine, Division of Endocrinology and Metabolism, Toronto General Hospital and University Health Network, Toronto, Ontario, Canada.
Leung
Nathalie
N
Lapointe
Nathalie
N
Szeto
Linda
L
Uffelman
Kristine D
KD
Giacca
Adria
A
Rouleau
Jean L
JL
Lewis
Gary F
GF
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D001786:Blood Glucose / Q000032:analysis; D001920:Bradykinin / Q000031:analogs & derivatives* / Q000494:pharmacology; D065168:Bradykinin Receptor Antagonists; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D007328:Insulin / Q000097:blood / Q000494:pharmacology; D007333:Insulin Resistance; D019808:Losartan / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D015260:Neprilysin / Q000037:antagonists & inhibitors*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011480:Protease Inhibitors / Q000494:pharmacology*; D011725:Pyridines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D017257:Ramipril / Q000494:pharmacology; D051381:Rats; D011924:Rats, Zucker; D044140:Receptor, Angiotensin, Type 1; D043782:Receptor, Bradykinin B2; D013841:Thiazepines / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D001786:Blood Glucose; D065168:Bradykinin Receptor Antagonists; D004791:Enzyme Inhibitors; D007328:Insulin; D011480:Protease Inhibitors; D011725:Pyridines; D044140:Receptor, Angiotensin, Type 1; D043782:Receptor, Bradykinin B2; D013841:Thiazepines; C106266:omapatrilat; C065679:icatibant; D019001:Nitric Oxide Synthase; D015260:Neprilysin; D005947:Glucose; D019808:Losartan; D017257:Ramipril; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester