OBJECTIVE -To investigate the pharmacodynamic profile and duration of action for five subcutaneous doses of insulin detemir (0.1, 0.2, 0.4, 0.8, and 1.6 units/kg; 1 unit ϭ 24 nmol) and one subcutaneous dose of NPH insulin (0.3 IU/kg; 1 IU ϭ 6 nmol). RESEARCH DESIGN AND METHODS-This single-center, randomized, doubleblind, six-period, crossover study was carried out as a 24-h isoglycemic clamp (7.2 mmol/l) in 12 type 1 diabetic patients.RESULTS -Duration of action for insulin detemir was dose dependent and varied from 5.7, to 12.1, to 19.9, to 22.7, to 23.2 h for 0.1, 0.2, 0.4, 0.8, and 1.6 units/kg, respectively. Interpolation of the dose-response relationships for AUC GIR (area under the glucose infusion rate curve) revealed that a detemir dose of 0.29 units/kg would provide the same effect as 0.3 IU/kg NPH but has a longer duration of action (16.9 vs. 12.7 h, respectively). Lower between-subject variability was observed for insulin detemir on duration of action (0.4 units/kg insulin detemir vs. 0.3 IU/kg NPH, P Ͻ 0.05) and GIR max (maximal glucose infusion rate) (0.2 and 0.4 units/kg insulin detemir vs. 0.3 IU/kg NPH, both P Ͻ 0.05). Assessment of endogenous glucose production (EGP) and peripheral glucose uptake (PGU) resulted in an AOC EGP (area over the EGP curve) of 636 mg/kg (95% CI 279 -879) vs. 584 (323-846) and an AUC PGU (area under the PGU curve) of 173 (47-316) vs. 328 (39 -617) for 0.29 units/kg detemir vs. 0.3 IU/kg NPH, respectively.CONCLUSIONS -This study shows that insulin detemir provides a flat and protracted pharmacodynamic profile. Diabetes Care 28:1107-1112, 2005T raditional basal insulin formulations such as NPH or zinc insulin have limitations such as variability in insulin absorption after subcutaneous injection, resulting in an unpredictable action profile increasing the risk of hypoglycemic episodes, and a pharmacodynamic profile requiring several injections to cover 24 h (1-4).Recently, long-acting insulin analogs have been biologically engineered to overcome these limitations (5-9). These insulin analogs make use of different principles for achieving a protracted insulin profile, such as changing the isoelectric point (insulin glargine) or acylation of the insulin molecule (insulin detemir). Previous studies have confirmed both a delayed and a sustained blood glucoselowering effect with insulin detemir compared with NPH insulin in healthy subjects (10,11). However, the results show that a higher molar dose of insulin detemir is needed to achieve comparable glycemic control similar to that observed with NPH insulin (10).The objective of the present trial was to describe the 24-h pharmacodynamic profile, including duration of action and dose-response relationship, of insulin detemir in subjects with type 1 diabetes and to compare this with NPH insulin. RESEARCH DESIGN ANDMETHODS -In this single-center, double-blind, six-period, randomized, dose-response trial, isoglycemic (7.2 mmol/l) subjects were randomized to a specific treatment sequence encompassing five dose levels of insulin dete...

Recent studies have suggested that n-3 fatty acids, abundant in fish oil, protect against high-fat diet-induced insulin resistance through peroxisome proliferator-activated receptor (PPAR)-␣ activation and a subsequent decrease in intracellular lipid abundance. To directly test this hypothesis, we fed PPAR-␣ null and wild-type mice for 2 weeks with isocaloric high-fat diets containing 27% fat from either safflower oil or safflower oil with an 8% fish oil replacement (fish oil diet). In both genotypes the safflower oil diet blunted insulin-mediated suppression of hepatic glucose production (P < 0.02 vs. genotype control) and PEPCK gene expression. Feeding wild-type mice a fish oil diet restored hepatic insulin sensitivity (hepatic glucose production [HGP], P < 0.002 vs. wild-type mice fed safflower oil), whereas in contrast, in PPAR-␣ null mice failed to counteract hepatic insulin resistance (HGP, P ‫؍‬ NS vs. PPAR-␣ null safflower oil-fed mice). In PPAR-␣ null mice fed the fish oil diet, safflower oil plus fish oil, hepatic insulin resistance was dissociated from increases in hepatic triacylglycerol and acyl-CoA but accompanied by a more than threefold increase in hepatic diacylglycerol concentration (P < 0.0001 vs. genotype control). These data support the hypothesis that n-3 fatty acids protect from high-fat diet-induced hepatic insulin resistance in a PPAR-␣-and diacylglycerol-dependent manner. Diabetes

Defects in liver and muscle glycogen synthesis are major factors contributing to postprandrial hyperglycemia in patients with type 2 diabetes. Therefore, activation of glycogen synthase through inhibition of glycogen synthase kinase (GSK)-3 represents a potential new therapeutic target. To examine this possibility, we performed oral glucose tolerance tests (OGTTs) and euglycemic-insulinemic clamp studies in Zucker diabetic fatty (fa/fa) rats before and after treatment with novel GSK-3 inhibitors. GSK-3 inhibition caused a 41 ؎ 2% (P < 0.001) and 26 ؎ 4% (P < 0.05) reduction in the area under the glucose and insulin concentration curves, respectively, during the OGTT. This improvement in glucose disposal could mostly be attributed to an approximate twofold increase in liver glycogen synthesis. In contrast, there was no significant increase in muscle glycogen synthesis despite an approximate threefold activation of muscle glycogen synthase activity. GSK-3 inhibitor treatment increased liver glycogen synthesis about threefold independent of insulin concentration during the clamp studies. In contrast, muscle glucose uptake and muscle glycogen synthesis were independent of drug treatment. GSK-3 inhibitor treatment lowered fasting hyperglycemia in diabetic rats by 6.0 ؎ 1.3 mmol/l but had no significant effect on glucose disposal during the clamp. In conclusion, GSK-3 inhibition significantly improved oral glucose disposal, mostly by increasing liver glycogen synthesis. These studies suggest that GSK-3 inhibition may represent an important new therapeutic target for treatment of patients with type 2 diabetes. Diabetes

To examine the mechanism by which fish oil protects against fat-induced insulin resistance, we studied the effects of control, fish oil, and safflower oil diets on peroxisomal content, fatty acyl-CoA, diacylglycerol, and ceramide content in rat liver and muscle. We found that, in contrast to control and safflower oil-fed rats, fish oil feeding induced a 150% increase in the abundance of peroxisomal acyl-CoA oxidase and 3-ketoacyl-CoA thiolase in liver but lacked similar effects in muscle. This was paralleled by an almost twofold increase in hepatic peroxisome content (both P < 0.002 vs. control and safflower). These changes in the fish oil-fed rats were associated with a more than twofold lower hepatic triglyceride/diacylglycerol, as well as intramuscular triglyceride/fatty acyl-CoA, content. In conclusion, these data strongly support the hypothesis that n-3 fatty acids protect against fat-induced insulin resistance by serving as peroxisome proliferator-activated receptor-α ligands and thereby induce hepatic, but not intramuscular, peroxisome proliferation. In turn, an increased hepatic β-oxidative capacity results in lower hepatic triglyceride/diacylglycerol and intramyocellular triglyceride/fatty acyl-CoA content.

Long-chain acyl-CoA esters (LCACoAs) are activated lipid species that represent key substrates in lipid metabolism. The relationship between lipid metabolism disorders and type 2 diabetes has attracted much attention to this class of metabolites. This paper presents a highly sensitive and robust on-line LC/MS(2) procedure for quantitative determination of LCACoAs from rat liver. A fast SPE method has been developed without the need for time-consuming evaporation steps for sample preparation. LCACoAs were separated with high resolution using a C18 reversed-phase column at high pH (10.5) with an ammonium hydroxide and acetonitrile gradient. Five LCACoAs (C16:0, C16:1, C18:0 C18:1, C18:2) were quantified by selective multireaction monitoring using a triple quadrupole mass spectrometer in positive electrospray ionization mode. It is possible to perform a neutral loss scan of 507 for lipid profiling of complex LCACoA mixtures in tissue extracts. The method presented was validated according to ICH guidelines for quantitative determination of five LCACoAs for physiological concentrations in 100-200 mg of tissue with accuracies ranging from 94.8 to 110.8%, interrun precisions between 2.6 and 12.2%, and intrarun precisions between 1.2 and 4.4%. Due to the high sensitivity of the developed method, the amount of tissue biopsied for reliable quantification can be reduced. This may be advantageous in the quantification of LCACoAs in humans.