PMT13, a pyrimidone analogue of thiazolidinedione improves insulin resistance-associated disorders in animal models of type 2 diabetes.
OBJECTIVE
To evaluate the antidiabetic and hypolipidaemic potential of a novel thiazolidinedione, PMT13, in different animal models of insulin resistance.


METHODS
PPAR transactivation study was performed in HEK293T cells using ligand binding domains of PPARalpha, gamma and delta. Insulin-resistant db/db and ob/ob mice were treated orally with different doses of PMT13 at 0.3-10 mg/kg/day for 15 and 14 days respectively. Zucker fa/fa rats were treated with 3 mg/kg (p.o.) dose of the compound. Plasma glucose, triglyceride, free fatty acid and insulin levels were measured. Liver glucose 6-phosphatase (G6-Ptase) and adipose lipoprotein lipase activity was measured in treated mice. Isolated rat aortic preparations preconstricted with phenylephrine were used to study the vascular relaxation potential of PMT13 in presence of insulin. A 28-day oral toxicity study was performed in Wistar rats.


RESULTS
PMT13 showed similar PPARgamma activation as rosiglitazone, but failed to show any activity against PPARalpha or PPARdelta. In obese and diabetic db/db and ob/ob mice, PMT13 showed better reduction in plasma glucose, triglyceride and insulin levels than rosiglitazone and an improvement in glucose tolerance. In insulin-resistant Zucker fa/fa rat model, PMT13 treatment showed better reduction in plasma triglyceride, free fatty acid and insulin levels than that of rosiglitazone. Treated mice showed decreased G6-Ptase activity in liver. The LPL activity was increased in post-heparin plasma and epididymal fat of treated db/db mice. In an isolated, precontracted rat aortic preparation, PMT13 treatment significantly increased insulin-induced relaxation. A 28-day oral toxicity study in rats showed no treatment-related adverse effects.


CONCLUSIONS
Our studies indicate that PMT13 is a potent activator of PPARgamma with antidiabetic, hypolipidaemic and insulin-sensitizing properties. Additionally, PMT13 inhibited liver G6-Ptase activity and increased lipoprotein lipase activity. It showed improvement in insulin-induced vasorelaxation. The compound also showed a good safety margin. Therefore, PMT13 can be a potential drug candidate for future development.
Discovery Biology, Dr Reddy's Research Foundation, Bollaram Road, Miyapur, Hyderabad, India. ranjanchakrabarti@drreddys.com
R
R
Chakrabarti
R K
RK
Vikramadithyan
M Prem
MP
Kumar
S K B
SK
Kumar
N V S
NV
Mamidi
P
P
Misra
J
J
Suresh
J
J
Hiriyan
C S
CS
Rao
R
R
Rajagopalan
D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D004195:Disease Models, Animal; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007333:Insulin Resistance; D008099:Liver / Q000187:drug effects; D051379:Mice; D008820:Mice, Obese; D011743:Pyrimidines / Q000627:therapeutic use; D011744:Pyrimidinones / Q000627:therapeutic use; D051381:Rats; D011924:Rats, Zucker; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D013844:Thiazoles / Q000627:therapeutic use*; D045162:Thiazolidinediones; D014157:Transcription Factors / Q000378:metabolism
C471831:5-(4-(2-(2-ethyl-4-methyl-6-oxo-1,6-dihydro-1-pyrimidinyl)ethoxy)phenylmethyl)thiazolidine-2,4-dione; D007004:Hypoglycemic Agents; D011743:Pyrimidines; D011744:Pyrimidinones; D018160:Receptors, Cytoplasmic and Nuclear; D013844:Thiazoles; D045162:Thiazolidinediones; D014157:Transcription Factors; C089946:2,4-thiazolidinedione