Albumin-bound basal insulin analogues (insulin detemir and NN344): comparable time-action profiles but less variability than insulin glargine in type 2 diabetes.

AIM: This study compared the time-action profiles of the novel albumin-bound basal insulin analogue NN344 with those of insulin detemir and insulin glargine in individuals with type 2 diabetes. METHODS: Twenty-seven insulin-treated men with type 2 diabetes [body mass index 30.8 +/- 2.6 kg/m(2) (mean +/- s.d.), haemoglobin A(1c) 7.6 +/- 1.1%] were enrolled in this randomized, double-blind trial and participated in six euglycaemic glucose clamp experiments [target blood glucose (BG) 5 mmol/l] each. Participants received NN344 in three experiments at a dose of 0.8, 1.6 and 2.8 dosing units (DU) (1 DU corresponds to 6 nmol NN344) per kilogram of body weight. In the other three experiments, the participants received 0.4, 0.8 and 1.4 U/kg of either insulin detemir or insulin glargine. The insulin preparations were characterized with regards to their effects on glucose infusion rates (GIRs) (in particular duration of action and within-subject and between-subject variabilities), BG, C-peptide, free fatty acids (FFA), endogenous glucose production (EGP) and peripheral glucose uptake (PGU) over 24 h post-dose. RESULTS: The mean GIR profiles for all three preparations were similar in shape/flatness and showed increasing effect (area under the curve for GIR: AUC-GIR(total)) with increasing dose [low dose: 647 +/- 580, 882 +/- 634, 571 +/- 647 mg/kg (insulin detemir vs. NN344 vs. insulin glargine]; medium dose: 1203 +/- 816, 1720 +/- 1109, 1393 +/- 1203 mg/kg and high dose: 2171 +/- 1344, 3119 +/- 1549, 2952 +/- 2028 mg/kg; p = 0.48]. The duration of action increased with rising doses of all insulin preparations, without major differences between treatments. BG remained below 7 mmol/l in nearly all the experiments. Within-subject variability was lower for the albumin-bound insulin analogues, insulin detemir and NN344, than for insulin glargine (p < 0.0001). Between-subject variability did not differ between treatments, nor did the effects on BG, C-peptide, FFA, EGP or PGU. CONCLUSIONS: In individuals with type 2 diabetes, the time-action profiles and the duration of action of the albumin-bound insulin analogues, insulin detemir and NN344, were comparable with those of insulin glargine, whereas within-subject variability in the metabolic effect was significantly lower. Therefore, insulin detemir and NN344 seem to be as well suited as insulin glargine for once-daily administration in type 2 diabetes. The better predictability may be an important characteristic of the albumin-bound analogues as insulin detemir has already been shown to improve hypoglycaemia.

Extracellular formation and uptake of adenosine during skeletal muscle contraction in the rat: role of adenosine transporters.

1. The existence of adenosine transporters in plasma membrane giant vesicles from rat skeletal muscles and in primary skeletal muscle cell cultures was investigated. In addition, the contribution of intracellularly or extracellularly formed adenosine to the overall extracellular adenosine concentration during muscle contraction was determined in primary skeletal muscle cell cultures. 2. In plasma membrane giant vesicles, the carrier-mediated adenosine transport demonstrated saturation kinetics with Km = 177 +/- 36 microM and Vmax = 1.9 +/- 0.2 nmol x ml(-1) x s(-1) (0.7 nmol (mg protein)(-1) x s(-1)). The existence of an adenosine transporter was further evidenced by the inhibition of the carrier-mediated adenosine transport in the presence of NBMPR (nitrobenzylthioinosine; 72% inhibition) or dipyridamol (64% inhibition; P < 0.05). 3. In primary skeletal muscle cells, the rate of extracellular adenosine accumulation was 5-fold greater (P < 0.05) with electrical stimulation than without electrical stimulation. Addition of the adenosine transporter inhibitor NBMPR led to a 57% larger (P < 0.05) rate of extracellular adenosine accumulation in the electro-stimulated muscle cells compared with control cells, demonstrating that adenosine is taken up by the skeletal muscle cells during contractions. 4. Inhibition of ecto-5'-nucleotidase with AOPCP in electro-stimulated cells resulted in a 70% lower (P < 0.05) rate of extracellular adenosine accumulation compared with control cells, indicating that adenosine to a large extent is formed in the extracellular space during contraction. 5. The present study provides evidence for the existence of an NBMPR-sensitive adenosine transporter in rat skeletal muscle. Our data furthermore demonstrate that the increase in extracellular adenosine observed during electro-stimulation of skeletal muscle is due to production of adenosine in the extracellular space of skeletal muscle and that adenosine is taken up rather than released by the skeletal muscle cells during contraction.

Distribution of adenosine A1, A2A and A2B receptors in human skeletal muscle.

Many important physiological functions of skeletal muscle, such as glucose uptake, contraction and blood flow, have been proposed to be regulated via the action of adenosine on adenosine receptors. The cellular location of adenosine receptors in skeletal muscle is however, not known. The present study examined the distribution of A1, A2A and A2B adenosine receptors in human skeletal muscle using immunohistochemistry. All three receptor types were localized to vascular smooth muscle and endothelial cells, only the adenosine A2A and A2B receptors were observed in the plasma membrane and cytosol of the skeletal muscle. The finding was supported by results from western-blotting analysis. The cytosolic staining of the adenosine A2A receptor was slightly more intense in the type I muscle fibres, whereas the A2B receptor was almost absent in type I fibres. The present findings demonstrate for the first time, direct evidence for the existence of A2A and A2B adenosine receptors but absence of the A1 receptor in the sarcolemma and cytosol of skeletal muscle cells. The data also show existence of all three of the A1, A2A and A2B adenosine receptors in vascular cells of skeletal muscle tissue.

Differential regulation of MAP kinase by contraction and insulin in skeletal muscle: metabolic implications.

We have investigated the activation of the extracellular signal-regulated kinases (ERK1 and ERK2) by muscle contraction and insulin in perfused rat skeletal muscle. Both stimuli activated ERK1 and ERK2 by an upstream kinase MAP/ERK kinase (MEK)-dependent mechanism, as the MEK inhibitor PD-98059 inhibited ERK phosphorylation. The presence of the phosphatidylinositol (PI) 3-kinase inhibitors LY-294002 and wortmannin totally eradicated ERK1 and ERK2 phosphorylation in response to insulin but not contraction. Insulin and muscle contraction activated muscle glucose transport, glycogen synthase, and amino acid transport independently of ERK signaling, whereas the PI 3-kinase inhibitors abolished the stimulatory effects of insulin but not those of contraction on these three cellular processes. We conclude that 1) insulin and contraction activate ERK signaling in skeletal muscle; 2) ERK signaling is not necessary for activation of glucose and amino acid transport or glycogen synthase activity by contraction and insulin in skeletal muscle; and 3) insulin-induced activation of MEK, the upstream activator of ERK, is dependent on PI 3-kinase, whereas contraction utilizes a different mechanism.

Suicide and attempted suicide in Greenland. A controlled study in Nuuk (Godthaab).

Suicidal behaviour in Eskimo populations has changed in pattern and quantity over the last decades. Rates have more than quadrupled and performers now are mainly young persons with obscure motivation. In a study from Greenland's major township all cases of attempted or completed suicide among Greenlanders are analysed for social, emotional, somatic, and environmental predisposing factors in comparison with a non-psychiatric, never-suicidal, matching group. Almost two per thousand of the adult population committed suicide yearly while attempts at suicide were five times as frequent. A quarrelsome, drinking, childhood home background was often found, at least as regards the attempters, who themselves frequently suffered from emotional conflicts with close contacts, alcohol affliction, criminality, and instability at work. Neither bereavement, cross-cultural exposure, broken homes, nor meteorological factors seemed to exert a significant influence. The results are discussed in relation to the social and cultural evolution of the Greenlandic society.