Integrated safety and efficacy analysis of dasiglucagon for the treatment of severe hypoglycaemia in individuals with type 1 diabetes.

AIMS: To perform an integrated analysis of the safety and efficacy of dasiglucagon, a glucagon analogue available in a ready-to-use aqueous formulation, to treat severe hypoglycaemia (SH) in type 1 diabetes (T1D). MATERIALS AND METHODS: An integrated analysis of dasiglucagon safety was conducted on data from two placebo-controlled trials (placebo-controlled pool) and two placebo-controlled and four non-placebo-controlled trials (broad pool) in adults with T1D. An integrated analysis of dasiglucagon efficacy was conducted of pooled data and within demographic subgroups from the two placebo-controlled and two non-placebo-controlled trials in adults with T1D. RESULTS: Dasiglucagon had a similar safety and tolerability profile to that of reconstituted glucagon. In the placebo-controlled datasets, no serious adverse events (AEs), AEs leading to withdrawal from the trial, or deaths were reported. The most common causally related AEs were nausea (56.5%) and vomiting (24.6%). The broad pool safety analysis showed similar results. Dasiglucagon efficacy in time to plasma glucose recovery from insulin-induced SH was similar to that of reconstituted glucagon (median 10.0 and 12.0 minutes, respectively) and superior to placebo (median 40.0 minutes; P < 0.0001). The median recovery time was consistent across all placebo-controlled trial subgroups. CONCLUSIONS: Dasiglucagon was well tolerated and effective as a rapid rescue agent for insulin-induced SH in people with T1D.

Insulin degludec, an ultra-long-acting basal insulin, once a day or three times a week versus insulin glargine once a day in patients with type 2 diabetes: a 16-week, randomised, open-label, phase 2 trial.

BACKGROUND: Insulin degludec is a new basal insulin that forms soluble multihexamer assemblies after subcutaneous injection, resulting in an ultra-long action profile. This study aimed to assess efficacy and safety of insulin degludec injected once a day or three times a week compared with insulin glargine once a day in insulin-naive people with type 2 diabetes, who were inadequately controlled with oral antidiabetic drugs. METHODS: In this 16-week, randomised, open-label, parallel-group phase 2 trial, participants aged 18­75 years with type 2 diabetes and glycosylated haemoglobin (HbA(1C)) of 7·0­11·0% were enrolled and treated at 28 clinical sites in Canada, India, South Africa, and the USA. Participants were randomly allocated in a 1:1:1:1 ratio by computer-generated block randomisation to receive insulin degludec either once a day or three times a week or insulin glargine once a day, all in combination with metformin. Investigators were masked to data until database release. The primary outcome was HbA(1C) after 16 weeks of treatment. Analyses were done by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00611884. FINDINGS: Of 367 patients screened, 245 were eligible for inclusion. 62 participants were randomly allocated to receive insulin degludec three times a week (starting dose 20 U per injection [1 U=9 nmol]), 60 to receive insulin degludec once a day (starting dose 10 U [1 U=6 nmol]; group A), 61 to receive insulin degludec once a day (starting dose 10 U [1 U=9 nmol]; group B), and 62 to receive insulin glargine (starting dose 10 U [1 U=6 nmol]) once a day. At study end, mean HbA(1C) levels were much the same across treatment groups, at 7·3% (SD 1·1), 7·4% (1·0), 7·5% (1·1), and 7·2% (0·9), respectively. Estimated mean HbA(1C) treatment differences from insulin degludec by comparison with insulin glargine were 0·08% (95% CI ­0·23 to 0·40) for the three dose per week schedule, 0·17% (­0·15 to 0·48) for group A, and 0·28% (­0·04 to 0·59) for group B. Few participants had hypoglycaemia and the number of adverse events was much the same across groups, with no apparent treatment-specific pattern. INTERPRETATION: Insulin degludec provides comparable glycaemic control to insulin glargine without additional adverse events and might reduce dosing frequency due to its ultra-long action profile. FUNDING: Novo Nordisk.

Measurement of free GH and bioactive IGF-I in non-diabetic haemodialysis patients treated with GH for 7 days.

BACKGROUND: End-stage renal failure (ESRF) patients demonstrate augmented growth hormone (GH) secretion, but normal insulin-like growth factor-I (IGF-I) concentrations, indicating a state of GH resistance. To test this hypothesis, we compared the IGF-I response with exogenous GH in haemodialysis patients and healthy controls, with special focus on free GH and bioactive IGF-I. METHODS: Ultrafiltered free GH and total GH were measured in serum collected hourly for 24 h at baseline and after 7 days of recombinant human (rh) GH (50 µg/kg/day) treatment in 11 non-diabetic haemodialysis patients and 10 matched controls. Serum levels of bioactive IGF-I (determined by cell-based IGF-I receptor activation assay), total IGF-I and the GH-binding protein (GHBP) were assayed twice daily. RESULTS: At baseline, patients showed elevated total GH (24 ± 5 versus 9 ± 1 µg/L × h, P < 0.02), free GH (21 ± 5 versus 7 ± 1 µg/L × h, P < 0.02), reduced GHBP (1.5 ± 0.3 versus 2.5 ± 0.2 nmol/L, P < 0.01), high-normal total IGF-I (173 ± 18 versus 135 ± 14 µg/L, P = 0.12) and subnormal bioactive IGF-I (2.1 ± 0.3 versus 2.8 ± 0.2 µg/L, P < 0.05) when compared with controls. After 7 days of rhGH treatment, there was a greater GH increase in the non-diabetic haemodialysis patients than in controls (total GH: 293 ± 33 versus 166 ± 13 µg/L × h, P < 0.001; free GH: 284 ± 40 versus 126 ± 15 µg/L × h, P < 0.001). GHB remained unaffected and total IGF-I increased to the same extent in patients and controls (701 ± 87 versus 572 ± 33 µg/L, P = 0.17), whereas bioactive IGF-I tended to be lower in patients (5.37 ± 0.55 versus 6.63 ± 0.25 µg/L, P < 0.10). When adjusting for the actual increments in plasma GH, the ability of exogenous GH to stimulate bioactive IGF-I levels was reduced by ~50% in ESRF (P < 0.02), whereas the response of total IGF-I remained normal (74%; P= 0.18) CONCLUSIONS: The study demonstrates that ESRF is associated with markedly elevated serum levels of free GH. Furthermore changes in bioactive, but not immunoreactive, IGF-I indicated that the hepatic sensitivity to GH was reduced by 50% in ESRF patients. Clearly, the physiological importance of our observations awaits further studies, but they suggest that changes in total IGF-I may not necessarily reflect changes in the endogenous activity of IGF-I in ESRF patients on GH treatment.

In vivo and in vitro microdialysis sampling of free fatty acids.

Microdialysis is a technique that allows continuous sampling of compounds from the interstitial fluid of different tissues with minimal influence on surrounding tissues and/or whole body function. In the present study, the feasibility of using microdialysis as a technique to sample free fatty acids (FFA) was investigated both in vitro and in vivo, by use of a high molecular weight (MW) cut-off membrane (3 MDa) and a push-pull system to avoid loss of perfusion fluid through the dialysis membrane. The relative recovery was examined in vitro for three different concentrations of radiolabelled oleic acid-BSA solutions (oleic acid:BSA molar ratio 1:1) and for various temperatures and flow rates. The recovery of oleic acid was found to be dependent on the concentration of analyte in the medium surrounding the membrane (17.3%, 29.0% and 30.6% for 50, 100 and 200 microM oleic acid-BSA solutions, respectively). Addition of 0.25% BSA to the perfusion fluid resulted, however, in a concentration-independent recovery of 31.4%, 28.1% and 28.1% for the 50, 100 and 200 microM solutions, respectively. The capability of the method to measure FFA together with glycerol was investigated in vivo in visceral adipose tissue of rats, before and after lipolytic treatment with the beta3-adrenergic agent, BRL37344. BRL37344 caused an increase in both dialysate FFA and glycerol, although the increase was markedly higher for glycerol, amounting to 24.5% and 329.2% increase from baseline, respectively. Subsequent in vitro test of probe performance revealed a decrease in the dialysing properties with regard to FFA, but not glycerol. This suggests that clogging of the membrane pores after 110 min prevented the measurement of the full FFA response in vivo.

Lower rates of hypoglycemia during maintenance treatment with insulin degludec/insulin aspart versus biphasic insulin aspart 30: a combined analysis of two Phase 3a studies in type 2 diabetes.

BACKGROUND: Insulin degludec/insulin aspart (IDegAsp) is a soluble coformulation of the basal analog insulin degludec and the rapid-acting prandial insulin aspart in a single injection. The present combined analysis of two Phase 3a trials compared the incidence of hypoglycemia in participants treated twice daily with IDegAsp or biphasic insulin aspart 30 (BIAsp 30). METHODS: Hypoglycemia data were analyzed from two similarly designed randomized controlled open-label treat-to-target Phase 3a clinical trials of adults with type 2 diabetes (T2D). Participants were treated twice daily with IDegAsp or BIAsp 30, with breakfast and their main evening meal. RESULTS: Over 26 weeks, the rates of overall confirmed, nocturnal confirmed and severe hypoglycemic events were 19%, 57%, and 39% lower, respectively, with IDegAsp (n = 504) than BIAsp 30 (n = 364); estimated rate ratios were 0.81 (95% confidence interval [CI] 0.67, 0.98; P = 0.0341), 0.43 (95% CI 0.31, 0.59; P = 0.0001), and 0.61 (95% CI 0.26, 1.45; P = NS). The between-treatment differences were more pronounced during the maintenance period (≥16 weeks); compared with BIAsp 30, rates of overall confirmed, nocturnal confirmed and severe hypoglycemic events with IDegAsp were 0.69 (95% CI 0.55, 0.87; -31%; P = 0.0015); 0.38 (95% CI 0.25, 0.58; -62%; P < 0.0001), and 0.16 (95% CI 0.04, 0.59; -84%; P = 0.0061), respectively. CONCLUSIONS: Compared with BIAsp 30 twice daily, IDegAsp twice daily provided similar improvements in glycemic control with a lower risk of hypoglycemia, particularly nocturnal hypoglycemia, in subjects with T2D previously treated with insulin.

Growth hormone affects both adiposity and voluntary food intake in old and obese female rats.

OBJECTIVE: To investigate whether the promotion of breakdown of body fat and the increased energy expenditure associated with growth hormone (GH) affect the voluntary food intake of an obese organism. DESIGN: Wistar rats (15 months old) were first fed either a high-fat (HF) or a low-fat (LF) diet for 10 weeks. In the subsequent treatment period, two saline groups continued with either the HF or the LF diet, and rats of three other groups had their diet shifted from HF to LF and were treated with saline, human GH (hGH) or rat GH (rGH). hGH and rGH were given in a dose of 4 mg/kg per day. After 21 days of treatment and registration of food intake, rats were killed, blood was collected and tissues were excised. RESULTS: The HF diet produced a significant (P<0.05) increase in weight of fat pads compared with the LF diet: 69+/-5 g compared with 48+/-2 g. The switch from HF to LF diet combined with injections of saline alone decreased the intake of metabolizable energy, but fat pad weight did not decrease significantly (69+/-5 g compared with 63+/-6 g). The latter value was significantly (P<0.05) decreased (to 37+/-3 g) in groups treated with either hGH or rGH. Both GH treatments increased serum IGF-I and muscle weight, whereas the activity of adipose tissue lipoprotein lipase decreased significantly (P<0.01). During the first 9 days of treatment, food intake was significantly (P<0.01) depressed, from 27+/-1 g/kg per day in control rats to 14+/-2 and 16+/-4 g/kg per day in the hGH and rGH groups respectively. CONCLUSION: This study demonstrates that breakdown of adipose tissue and a transient decrease in voluntary food intake are parallel consequences of GH treatment in old and obese rats, and that the actions of hGH and rGH are very similar.

Elderly patients with diabetes experience a lower rate of nocturnal hypoglycaemia with insulin degludec than with insulin glargine: a meta-analysis of phase IIIa trials.

BACKGROUND AND OBJECTIVE: Elderly patients with diabetes are more vulnerable to the occurrence and effects of hypoglycaemia; therefore, treatments with low risk of hypoglycaemia are preferred in this population. This study aimed to compare hypoglycaemia rates between insulin degludec (IDeg) and insulin glargine (IGlar) in elderly patients. METHODS: Hypoglycaemia data from patients ≥65 years of age with type 1 (T1DM) or type 2 (T2DM) diabetes from seven randomised, treat-to-target phase IIIa trials were used to compare IDeg and IGlar in a pre-planned meta-analysis. Overall, 917/4345 (21 %) randomised patients in the seven trials were elderly (634 IDeg, 283 IGlar). Overall confirmed hypoglycaemia was defined as <3.1 mmol/L or severe hypoglycaemia (symptoms requiring external assistance). Nocturnal hypoglycaemia included confirmed episodes from 0001 to 0559 hours (inclusive). Treatment comparisons of hypoglycaemia in T1DM patients were not performed due to low numbers of elderly patients with T1DM randomised (43 IDeg, 18 IGlar); statistical comparisons were also not made for severe hypoglycaemia due to the low number of events. RESULTS: In elderly patients with T2DM, the rate of overall confirmed hypoglycaemia was significantly lower with IDeg than IGlar [estimated rate ratio (ERR) 0.76 (0.61; 0.95)95 % CI]; nocturnal confirmed hypoglycaemia was also significantly lower with IDeg [ERR 0.64 (0.43; 0.95)95 % CI]. Confirmed hypoglycaemia occurred in the majority of T1DM patients, whereas severe episodes occurred infrequently and at similar rates in both treatment groups in T1DM and T2DM. CONCLUSION: Results of this pre-planned meta-analysis in elderly patients with diabetes demonstrate a significant reduction in hypoglycaemic events with IDeg relative to IGlar.

Efficacy and safety of insulin degludec three times a week versus insulin glargine once a day in insulin-naive patients with type 2 diabetes: results of two phase 3, 26 week, randomised, open-label, treat-to-target, non-inferiority trials.

BACKGROUND: Results of an exploratory phase 2 study showed that insulin degludec, a basal insulin with an action profile of longer than 42 h, provided similar glycaemic control when injected three times a week (IDeg 3TW) to once-daily insulin glargine (IGlar OD). To provide further evidence, we did two phase 3 trials to compare the efficacy and safety of IDeg 3TW with IGlar OD in insulin-naive patients with type 2 diabetes. METHODS: In two 26 week, randomised, open-label, parallel group, non-inferiority trials IDeg was injected Monday, Wednesday, and Friday before breakfast (IDeg 3TW(AM)) in the AM trial (94 sites in seven countries) or with the evening meal (IDeg 3TW(PM)) in the PM trial (89 sites in seven countries), and compared with IGlar OD. Adults with type 2 diabetes (HbA(1c) 7.0-10.0%; body-mass index ≤45 kg/m(2)) were randomly allocated (1:1) without stratification by a central interactive response system to IDeg 3TW or IGlar OD. Both groups continued taking metformin with or without dipeptidyl peptidase-4 inhibitors. Insulin was titrated to achieve a prebreakfast self-monitored blood glucose (SMBG) concentration of between 3.9 and less than 5.0 mmol/L. The primary outcome was non-inferiority of IDeg 3TW compared with IGlar OD, as assessed by change in HbA(1c) from baseline to 26 weeks (non-inferiority limit of 0.4%) by ANOVA in an intent-to-treat analysis (full analysis set). These trials are registered with ClinicalTrials.gov, numbers NCT01068678 and NCT01076647. FINDINGS: We recruited 460 patients for the AM trial (IDeg 3TW(AM), n=230; IGlar OD, n=230) and 467 patients for the PM trial (IDeg 3TW(PM), n=233; IGlar OD, n=234). After 26 weeks, mean HbA decreased by 0.9% (IDeg 3TW(AM)) and 1.3% (IGlar OD) in the AM trial, and by 1.1% (IDeg 3TW(PM)) and 1.4% (IGlar OD) in the PM trial. Non-inferiority was not confirmed in either trial (estimated treatment difference [IDeg 3TW(AM)-IGlar OD] 0.34%, 95% CI 0.18-0.51; [IDeg 3TW(PM)-IGlar OD] 0.26%, 0.11-0.41). Across the two trials, rates of confirmed hypoglycaemia (SMBG <3.1 mmol/L or severe [needing assistance]) ranged from 1.0 to 1.6 episodes per patient-year and were similar for IDeg 3TW(AM) and IGlar OD (estimated rate ratio [ERR] 1.04, 95% CI 0.69-1.55), but higher for IDeg 3TW(PM) than for IGlar OD (ERR 1.58, 1.03-2.43). The rate of nocturnal confirmed hypoglycaemia was higher for IDeg 3TW(AM) than for IGlar OD (ERR 2.12, 1.08-4.16); we noted no significant difference between IDeg 3TW(PM) and IGlar OD (ERR 0.60, 0.21-1.69). INTERPRETATION: The inferior glycaemic control and increased risk of hypoglycaemia with IDeg 3TW compared with IGlar OD do not support a three-times-weekly dosing regimen. FUNDING: Novo Nordisk.

The efficacy and safety of insulin degludec given in variable once-daily dosing intervals compared with insulin glargine and insulin degludec dosed at the same time daily: a 26-week, randomized, open-label, parallel-group, treat-to-target trial in individuals with type 2 diabetes.

OBJECTIVE: The requirement to inject current basal insulin analogs at a fixed time each day may complicate adherence and compromise glycemic control. This trial evaluated the efficacy and safety of varying the daily injection time of insulin degludec (IDeg), an ultra-long-acting basal insulin. RESEARCH DESIGN AND METHODS: This 26-week, open-label, treat-to-target trial enrolled adults (≥18 years) with type 2 diabetes who were either insulin naïve and receiving oral antidiabetic drugs (OADs) (HbA(1c) = 7-11%) or previously on basal insulin ± OAD(s) (HbA(1c) = 7-10%). Participants were randomized to 1) once-daily (OD) IDeg in a prespecified dosing schedule, creating 8-40-h intervals between injections (IDeg OD Flex; n = 229); 2) once-daily IDeg at the main evening meal (IDeg OD; n = 228); or 3) once-daily insulin glargine at the same time each day (IGlar OD; n = 230). The primary outcome was noninferiority of IDeg OD Flex to IGlar OD in HbA(1c) reduction after 26 weeks. RESULTS: After 26 weeks, IDeg OD Flex, IDeg OD, and IGlar OD improved HbA(1c) by 1.28, 1.07, and 1.26% points, respectively (estimated treatment difference [IDeg OD Flex - IGlar OD]: 0.04% points [-0.12 to 0.20], confirming noninferiority). No statistically significant differences in overall or nocturnal hypoglycemia were found between IDeg OD Flex and IGlar OD. Comparable glycemic control and rates of hypoglycemia were seen with IDeg OD Flex and IDeg OD. Adverse event profiles were similar across groups. CONCLUSIONS: The use of extreme dosing intervals of 8-40 h demonstrates that the daily injection time of IDeg can be varied without compromising glycemic control or safety.

Insulin degludec versus insulin glargine in insulin-naive patients with type 2 diabetes: a 1-year, randomized, treat-to-target trial (BEGIN Once Long).

OBJECTIVE: To compare ultra-long-acting insulin degludec with glargine for efficacy and safety in insulin-naive patients with type 2 diabetes inadequately controlled with oral antidiabetic drugs (OADs). RESEARCH DESIGN AND METHODS: In this 1-year, parallel-group, randomized, open-label, treat-to-target trial, adults with type 2 diabetes with A1C of 7-10% taking OADs were randomized 3:1 to receive once daily degludec or glargine, both with metformin. Insulin was titrated to achieve prebreakfast plasma glucose (PG) of 3.9-4.9 mmol/L. The primary end point was confirmation of noninferiority of degludec to glargine in A1C reduction after 52 weeks in an intent-to-treat analysis. RESULTS: In all, 1,030 participants (mean age 59 years; baseline A1C 8.2%) were randomized (degludec 773, glargine 257). Reduction in A1C with degludec was similar (noninferior) to that with glargine (1.06 vs. 1.19%), with an estimated treatment difference of degludec to glargine of 0.09% (95% CI -0.04 to 0.22). Overall rates of confirmed hypoglycemia (PG <3.1 mmol/L or severe episodes requiring assistance) were similar, with degludec and glargine at 1.52 versus 1.85 episodes/patient-year of exposure (PYE). There were few episodes of nocturnal confirmed hypoglycemia in the overall population, and these occurred at a lower rate with degludec versus glargine (0.25 vs. 0.39 episodes/PYE; P = 0.038). Similar percentages of patients in both groups achieved A1C levels <7% without hypoglycemia. End-of-trial mean daily insulin doses were 0.59 and 0.60 units/kg for degludec and glargine, respectively. Adverse event rates were similar. CONCLUSIONS: Insulins degludec and glargine administered once daily in combination with OADs provided similar long-term glycemic control in insulin-naive patients with type 2 diabetes, with lower rates of nocturnal hypoglycemia with degludec.

The anorectic response to growth hormone in obese rats is associated with an increased rate of lipid oxidation and decreased hypothalamic galanin.

The aim of this study was to demonstrate differential effects of growth hormone (GH) on food intake in lean and obese rats and to investigate whether an anticipated anorectic response in obese rats might be associated with increased lipid oxidation and altered hypothalamic neuropeptide levels. GH (4 mg/kg/day) was administered during 5-21 days to non-obese and obese rats. Whereas GH stimulated food intake in the non-obese rats, the obese animals responded with a significantly (p<0.05) suppressed food intake for 4-5 days. On day 4, the obese rats injected with GH and those injected with vehicle consumed 9.2 ± 0.66 g and 12.7 ± 1.05 g, respectively. The suppression of food intake was associated with significantly (p<0.05) increased lipid oxidation. A similar, but statistically not verified, trend was seen in pair-fed rats not exposed to GH. However, while these animals appeared to economize their energy expenditure, the GH-exposed animals did not, thus creating a significant (p<0.05) difference between these two groups. The increased lipid oxidation and energy expenditure observed in the rats exposed to GH were associated with significantly (p<0.05) decreased levels of hypothalamic galanin (111 ± 33.2 pmol/g vs. those of the pair-fed controls: 228.5 ± 49.4 pmol/g). This difference was, however, not sustained. Thus, on day 21 both hypothalamic galanin and the food intake in the GH group were back to normal. Hypothalamic NPY remained unchanged by GH at all times. In conclusion, the present study suggests that increased lipid oxidation and decreased hypothalamic galanin are components in the mechanism by which GH inhibits food intake in an obese phenotype.

Insulin degludec in type 1 diabetes: a randomized controlled trial of a new-generation ultra-long-acting insulin compared with insulin glargine.

OBJECTIVE: Insulin degludec (IDeg) is a basal insulin that forms soluble multihexamers after subcutaneous injection, resulting in an ultra-long action profile. We assessed the efficacy and safety of IDeg formulations administered once daily in combination with mealtime insulin aspart in people with type 1 diabetes. RESEARCH DESIGN AND METHODS: In this 16-week, randomized, open-label trial, participants (mean: 45.8 years old, A1C 8.4%, fasting plasma glucose [FPG] 9.9 mmol/L, BMI 26.9 kg/m(2)) received subcutaneous injections of IDeg(A) (600 µmol/L; n = 59), IDeg(B) (900 µmol/L; n = 60), or insulin glargine (IGlar; n = 59), all given once daily in the evening. Insulin aspart was administered at mealtimes. RESULTS At 16 weeks, mean A1C was comparable for IDeg(A) (7.8 ± 0.8%), IDeg(B) (8.0 ± 1.0%), and IGlar (7.6 ± 0.8%), as was FPG (8.3 ± 4.0, 8.3 ± 2.8, and 8.9 ± 3.5 mmol/L, respectively). Estimated mean rates of confirmed hypoglycemia were 28% lower for IDeg(A) compared with IGlar (rate ratio [RR]: 0.72 [95% CI 0.52-1.00]) and 10% lower for IDeg(B) compared with IGlar (RR: 0.90 [0.65-1.24]); rates of nocturnal hypoglycemia were 58% lower for IDeg(A) (RR: 0.42 [0.25-0.69]) and 29% lower for IDeg(B) (RR: 0.71 [0.44-1.16]). Mean total daily insulin dose was similar to baseline. The frequency and pattern of adverse events was similar between insulin treatments. CONCLUSIONS: In this clinical exploratory phase 2 trial in people with type 1 diabetes, IDeg is safe and well tolerated and provides comparable glycemic control to IGlar at similar doses, with reduced rates of hypoglycemia.

Effect of the cannabinoid receptor-1 antagonist rimonabant on lipolysis in rats.

The cannabinoid receptor 1 antagonist, rimonabant, reduces food intake and body weight, but contradictory findings have been reported as to whether the weight-reducing effect is fully accounted for by the reduced food intake or if rimonabant also mediates a lipolytic effect. In the present study, the effect on weight loss was studied in diet-induced obese rats after 3 days and 3 weeks of exposure to rimonabant, respectively. Induction of lipolysis was examined following acute administration and following 3 weeks of repeated dosing. Rimonabant-treated rats lost significantly more weight than their food-restricted controls. This effect was most pronounced in the beginning of the treatment period. No increase in lipolytic activity was found after 3 weeks of repeated dosing as measured by microdialysis in adipose tissue whereas acute administration of 10mg/kg produced a significant increase in microdialysate levels of glycerol illustrating an acute stimulation of lipolysis. No equivalent increase in glycerol was, however, observed in vitro following incubation of isolated rat adipocytes with rimonabant. This finding excludes a direct lipolytic action of rimonabant on tissue level. Instead, administration of 10mg/kg produced a significant increase in noradrenaline excretion in diet-induced obese rats, suggesting an increase in sympathoadrenal activity. In conclusion, the present study suggests an acute lipolytic effect of rimonabant mediated through activation of the sympathoadrenal system.

Treatment of Obesity Using GH.

The obesity epidemic calls for complementary treatment possibilities in addition to lifestyle changes. One of the important regulators of lipid homeostasis is growth hormone (GH). Clinical trials have tested if GH can reduce obesity in humans. The mechanisms underlying the response to GH administration have also been investigated in animal models of human obesity. A literature search yielded 19 randomized placebo-controlled clinical studies and several animal studies investigating chronic GH treatment of obesity. Significant effects were found in some of the larger trials. One clinical trial showed significantly increased weight loss due to GH treatment, and in seven trials, a significant reduction of fat mass was found. The improvements observed were modest, but even minor improvements have been shown to be beneficial, especially if the reduction in fat mass includes visceral adipose tissue, as was reported in three of six trials. In principle, animal data support the clinical observations although the reduction of fat mass was more dramatic than observed in humans. The mechanisms resulting in lipid mobilization most likely include adipose tissue lipo-protein lipase (LPL) inhibition and antagonization of the anti-lipolytic activity of insulin. By feeding a restricted amount of a high fat diet to GH exposed rats hyper-insulinemia was avoided, loss of body fat was accelerated and metabolic markers were improved. Provision of a diet suitable for the metabolic conditions during GH treatment shows promise for improving metabolic control and can perhaps increase the efficacy and/or widen the therapeutic window of GH.