Metformin use and risk of lactic acidosis in people with diabetes with and without renal impairment: a cohort study in Denmark and the UK.

AIMS: To assess risk of lactic acidosis among metformin users compared with other glucose-lowering agent users, according to renal function. METHODS: Using routine registries and databases, we conducted a cohort study. Of 43 580 metformin and 37 788 other glucose-lowering agent users in northern Denmark and 102 688 metformin and 28 788 other glucose-lowering agent users in the UK during 2001-2011, we identified lactic acidosis using diagnostic codes. We calculated the incidence rates of lactic acidosis in metformin and other glucose-lowering agent users overall and according to baseline estimated GFR (eGFR) levels. RESULTS: In Denmark, the incidence rates of lactic acidosis were 11.6 (95% CI 7.0-18.1) and 1.8 (95% CI 0.4-5.4) per 100 000 person-years of metformin use and of other glucose-lowering agent use, respectively. In the UK, the corresponding lactic acidosis incidence rates were 6.8 (95% CI 4.6-9.6) and 1.0 (95% CI 0.01-5.7) per 100 000 person-years of metformin use and of other glucose-lowering agent use. The incidence rates increased with decreasing baseline eGFR in both countries. Of the metformin-exposed people with lactic acidosis, 37% in Denmark and 34% in the UK experienced a decline in renal function in the year before the diagnosis. CONCLUSIONS: Risk of lactic acidosis was higher in metformin users than in other glucose-lowering agent users, and increased with decreasing eGFR, although this could be attributable to surveillance bias; however, diagnosed lactic acidosis was rare and can occur regardless of renal function.

Effectiveness of intensification therapies in Danes with Type 2 diabetes who use basal insulin: a population-based study.

AIMS: To examine the usage and real-life effectiveness of intensification therapies in people with Type 2 diabetes treated with basal insulin. METHODS: We used population-based healthcare databases in Denmark during 2000-2012 to identify all individuals with a first basal insulin prescription (with or without oral drugs), and evaluated subsequent intensification therapy with bolus insulin, premixed insulin or glucagon-like peptide-1 (GLP-1) receptor agonists. Poisson regression was used to compute the adjusted relative risks of reaching glycaemic control targets. RESULTS: We included 7034 initiators of basal insulin (median age 64 years, diabetes duration 5.3 years, 84% with oral co-medication and median (interquartile range) pre-insulin HbA1c level 77 (65-92) mmol/mol [9.2% (8.1-10.6%)]. Of these, 3076 (43.7%) received intensification therapy after a median of 11 months: 58.5% with premixed insulin, 29.0% with bolus insulin, 10.6% with GLP-1 receptor agonists, and 1.9% with more than one add-on. Overall, 22% had attained an HbA1c level of < 53 mmol/mol (< 7%) by 3-6 months after intensification, while 38% attained an HbA1c < 58 mmol/mol (< 7.5%). Compared with premixed insulin intensification, attainment of HbA1c < 53 and < 58 mmol/mol was similar with bolus insulin add-on [adjusted relative risk 1.03 (95% CI 0.86-1.24) and 1.02 (95% CI 0.91-1.15), and higher for GLP-1 receptor agonist add-on [adjusted relative risk 1.56 (95% CI 1.27-1.92) and 1.27 (1.10-1.47)]. CONCLUSIONS: Among people with Type 2 diabetes, 22 and 38% reached a target HbA1c < 53 mmol/mol (< 7%) or < 58 mmol/mol (< 7.5%), respectively, after intensification of their basal insulin therapy. Compared with premixed insulin, target attainment was similar with bolus insulin and higher with GLP-1 receptor agonists.

Patient-level predictors of achieving early glycaemic control in Type 2 diabetes mellitus: a population-based study.

AIMS: To identify individual predictors of early glycaemic control in people with Type 2 diabetes mellitus after initiation of first glucose-lowering drug treatment in everyday clinical practice. METHODS: Using medical registries, we identified a population-based cohort of people with a first-time glucose-lowering drug prescription in Northern Denmark in the period 2000-2012. We used Poisson regression analysis to examine patient-level predictors of success in reaching early glycaemic control [HbA1c target of < 53 mmol/mol (7%)] < 6 months after treatment start. RESULTS: Among the 38 418 people (median age 63 years), 27 545 (72%) achieved early glycaemic control. The strongest predictor of achieving early control was pre-treatment HbA1c level; compared with a pre-treatment HbA1c level of ≤ 58 mmol/mol (7.5%), the adjusted relative risks of attaining early control were 0.63 (95% CI 0.61-0.64) for baseline HbA1c levels of > 58 and ≤ 75 mmol/mol (> 7.5 and ≤ 9%), and 0.58 (95% CI 0.57-0.59) for a baseline HbA1c level of > 9% (> 75 mmol/mol). All other examined predictors were only weakly associated with the chance of achieving early control. After adjustment, the only characteristics that remained independently associated with early control (in addition to high baseline HbA1c ) were being widowed (adjusted relative risk 0.95; 95% CI 0.93-0.97) and having a high Charlson comorbidity index score (score ≥ 3; adjusted relative risk 0.94; 95% CI 0.90-0.97). CONCLUSIONS: In a real-world clinical setting, people with Type 2 diabetes mellitus initiating glucose-lowering medication had a similar likelihood of achieving glycaemic control, regardless of sex, age, comorbidities and other individual factors; the only strong and potentially modifiable predictor was HbA1c before therapy start.

Early glycaemic control among patients with type 2 diabetes and initial glucose-lowering treatment: a 13-year population-based cohort study.

AIM: To examine real-life time trends in early glycaemic control in patients with type 2 diabetes between 2000 and 2012. METHODS: We used population-based medical databases to ascertain the association between achievement of glycaemic control with initial glucose-lowering treatment in patients with incident type 2 diabetes in Northern Denmark. Success in reaching glycated haemoglobin (HbA1c) goals within 3-6 months was examined using regression analysis. RESULTS: Of 38 418 patients, 91% started with oral glucose-lowering drugs in monotherapy. Metformin initiation increased from 32% in 2000-2003 to 90% of all patients in 2010-2012. Pretreatment (interquartile range) HbA1c levels decreased from 8.9 (7.6-10.7)% in 2000-2003 to 7.0 (6.5-8.1)% in 2010-2012. More patients achieved an HbA1c target of <7% (<53 mmol/mol) in 2010-2012 than in 2000-2003 [80 vs 60%, adjusted relative risk (aRR) 1.10, 95% confidence interval (CI) 1.08-1.13], and more achieved an HbA1c target of <6.5% [(<48 mmol/mol) 53 vs 37%, aRR 1.07 95% CI 1.03-1.11)], with similar success rates observed among patients aged <65 years without comorbidities. Achieved HbA1c levels were similar for different initiation therapies, with reductions of 0.8% (from 7.3 to 6.5%) on metformin, 1.5% (from 8.1 to 6.6%) on sulphonylurea, 4.0% (from 10.4 to 6.4%) on non-insulin combination therapies, and 3.8% (from 10.3 to 6.5%) on insulin monotherapy. CONCLUSIONS: Pretreatment HbA1c levels in patients with incident type 2 diabetes have decreased substantially, which is probably related to earlier detection and treatment in accordance with changing guidelines. Achievement of glycaemic control has improved, but 20% of patients still do not attain an HbA1c level of <7% within the first 6 months of initial treatment.

Dose-response effects of free fatty acids on glucose and lipid metabolism during somatostatin blockade of growth hormone and insulin in humans.

CONTEXT: GH and other stress hormones stimulate lipolysis, which may result in free fatty acid (FFA)-mediated insulin resistance. However, there are also indications that FFAs in the very low physiological range have the same effect. OBJECTIVE: The objective of the study was to address systematically the dose-response relations between FFAs and insulin sensitivity. DESIGN: We therefore examined eight healthy men for 8 h (6 h basal and 2 h glucose clamp) on four occasions. INTERVENTION: Intralipid was infused at varying rates (0, 3, 6, 12 microl.kg(-1).min(-1)); lipolysis was blocked by acipimox; and endogenous GH, insulin, and glucagon secretion was blocked by somatostatin and subsequently replaced at fixed rates. RESULTS: This resulted in four different FFA levels between 50 and 2000 micromol/liter, with comparable levels of insulin and counterregulatory hormones. Both in the basal state and during insulin stimulation, we saw progressively decreased glucose disposal, nonoxidative glucose disposal, and forearm muscle glucose uptake at FFA levels above 500 micromol/liter. Apart from forearm glucose uptake, the very same parameters were decreased at low FFA levels (approximately 50 micromol/liter). FFA rate of disposal was linearly related to the level of FFAs, whereas lipid oxidation reached a maximum at FFA levels approximately 1000 micromol/liter. CONCLUSION: In the presence of comparable levels of all major metabolic hormones, insulin sensitivity peaks at physiological levels of FFAs with a gradual decrease at elevated as well as suppressed FFA concentrations. These data constitute comprehensive dose-response curves for FFAs in the full physiological range from close to zero to above 2000 micromol/liter.

The protein-retaining effects of growth hormone during fasting involve inhibition of muscle-protein breakdown.

The metabolic response to fasting involves a series of hormonal and metabolic adaptations leading to protein conservation. An increase in the serum level of growth hormone (GH) during fasting has been well substantiated. The present study was designed to test the hypothesis that GH may be a principal mediator of protein conservation during fasting and to assess the underlying mechanisms. Eight normal subjects were examined on four occasions: 1) in the basal postabsorptive state (basal), 2) after 40 h of fasting (fast), 3) after 40 h of fasting with somatostatin suppression of GH (fast-GH), and 4) after 40 h of fasting with suppression of GH and exogenous GH replacement (fast+GH). The two somatostatin experiments were identical in terms of hormone replacement (except for GH), meaning that somatostatin, insulin, glucagon and GH were administered for 28 h; during the last 4 h, substrate metabolism was investigated. Compared with the GH administration protocol, IGF-I and free IGF-I decreased 35 and 70%, respectively, during fasting without GH. Urinary urea excretion and serum urea increased when participants fasted without GH (urea excretion: basal 392 +/- 44, fast 440 +/- 32, fast-GH 609 +/- 76, and fast+GH 408 +/- 36 mmol/24 h, P < 0.05; serum urea: basal 4.6 +/- 0.1, fast 6.2 +/- 0.1, fast-GH 7.0 +/- 0.2, and fast+GH 4.3 +/- 0.2 mmol/1, P < 0.01). There was a net release of phenylalanine across the forearm, and the negative phenylalanine balance was higher during fasting with GH suppression (balance: basal 9 +/- 3, fast 15 +/- 6, fast-GH 17 +/- 4, and fast+GH 11 +/- 5 nmol/min, P < 0.05). Muscle-protein breakdown was increased among participants who fasted without GH (phenylalanine rate of appearance: basal 17 +/- 4, fast 26 +/- 9, fast-GH 33 +/- 7, fast+GH 25 +/- 6 nmol/min, P < 0.05). Levels of free fatty acids and oxidation of lipid decreased during fasting without GH (P < 0.01). In summary, we find that suppression of GH during fasting leads to a 50% increase in urea-nitrogen excretion, together with an increased net release and appearance rate of phenylalanine across the forearm. These results demonstrate that GH-possibly by maintenance of circulating concentrations of free IGF-I--is a decisive component of protein conservation during fasting and provide evidence that the underlying mechanism involves a decrease in muscle protein breakdown.

Early narrowed afferent arteriole is a contributor to the development of hypertension.

The kidney is probably critically involved in the development of essential hypertension, as in many genetic models of hypertension. We have investigated whether a narrowed renal afferent arteriole is involved in the pathogenesis of hypertension in spontaneously hypertensive rats. Systolic blood pressure of 37 F2 generation spontaneously hypertensive rats/Wistar-Kyoto rats was measured at age 7 weeks. The right kidney was removed, and lumen diameter and media cross-sectional area of the afferent arterioles were measured after having been fixed while relaxed and under a transmural pressure of 100 mm Hg. The uninephrectomized rats continued until age 23 weeks, when mean blood pressure was measured. Mean blood pressure at 23 weeks was negatively correlated with lumen diameter at 7 weeks. Quartile analysis based on lumen diameter at 7 weeks showed that compared with rats in the top lumen diameter quartile, rats in the bottom lumen diameter quartile had a reduced media cross-sectional area at 7 weeks (17%), the same systolic blood pressure at 7 weeks, and an increased (16%) mean blood pressure at 23 weeks. We conclude that in spontaneously hypertensive rats a narrowed lumen of distal afferent arterioles at 7 weeks contributes to later development of increased blood pressure. This reduced lumen could be caused by inhibited renal afferent arteriole growth.

Continuation of growth hormone (GH) substitution during fasting in GH-deficient patients decreases urea excretion and conserves protein synthesis.

The consequences of GH deficiency during conditions in which endogenous GH release is acutely stimulated are largely unknown. Short-term fasting constitutes a robust GH stimulus, but the metabolic significance of GH during fasting is uncertain. To address both of these issues, we therefore evaluated the effect of GH on substrate metabolism during fasting in adults with GH deficiency. Seven hypopituitary GH-deficient patients were each studied twice during a 40-h fast: once with GH replacement continued and once with GH discontinued during the fast. After 40 h of fasting, protein synthesis and turnover were higher with than without GH replacement [phenylalanine incorporation (micromol/kg fat free mass/h): 36.6 +/- 1.2 (GH) vs. 32.8 +/- 1.4, P < 0.05; phenylalanine flux (micromol/kg fat free mass/h): 41.3 +/- 1.0 (GH) vs. 38.0 +/- 1.8, P < 0.05]. During continued GH replacement, urea excretion decreased during nighttime [urea excretion (mmol/24 h): 269 +/- 51 (GH) vs. 390 +/- 69, P < 0.05], and a significant decline in urea-N synthesis rate was found [urea-N synthesis rate (mmol/h): 14.7 +/- 1.6 (GH) vs. 21.1 +/- 2.2, P < 0.01]. GH replacement was associated with increased lipid oxidation [lipid oxidation (mg/kg per min): 0.91 +/- 0.07 (GH) vs. 0.70 +/- 0.03, P < 0.05]. Finally, continuation of GH induced moderate elevations in plasma glucose levels without significant changes in total glucose turnover or oxidation. In summary, continued GH substitution during fasting conserves nitrogen, which involves stimulation or maintenance of protein synthesis. Our data support the importance of GH replacement in hypopituitary adults.

Continuation of growth hormone (GH) therapy in GH-deficient patients during transition from childhood to adulthood: impact on insulin sensitivity and substrate metabolism.

The appropriate management of GH-deficient patients during transition from childhood to adulthood has not been reported in controlled trials, even though there is evidence to suggest that this phase is associated with specific problems in relation to GH sensitivity. An issue of particular interest is the impact of GH substitution on insulin sensitivity, which normally declines during puberty. We, therefore, evaluated insulin sensitivity (euglycemic glucose clamp) and substrate metabolism in 18 GH-deficient patients (6 females and 12 males; age, 20 +/- 1 yr; body mass index, 25 +/- 1 kg/m2) in a placebo-controlled, parallel study. Measurements were made at baseline, where all patients were on their regular GH replacement, after 12 months of either continued GH (0.018 +/- 0.001 mg/kg day) or placebo, and finally after 12 months of open phase GH therapy (0.016 mg/kg x day). Before study entry GH deficiency was reconfirmed by a stimulation test. During the double-blind phase, insulin sensitivity and fat mass tended to increase in the placebo group [deltaM-value (mg/kg x min), -0.7 +/- 1.1 (GH) vs. 1.3 +/- 0.8 (placebo), P = 0.18; deltaTBF (kg), 0.9 +/- 1.2 (GH) vs. 4.4 +/- 1.6 (placebo), P = 0.1]. Rates of lipid oxidation decreased [delta lipid oxidation (mg/kg x min), 0.02 +/- 0.14 (GH) vs. -0.32 +/- 0.13 (placebo), P < 0.05], whereas glucose oxidation increased in the placebo-treated group (P < 0.05). In the open phase, a decrease in insulin sensitivity was found in the former placebo group, although they lost body fat and increased fat-free mass [M-value (mg/kg x min), 5.1 +/- 0.7 (placebo) vs. 3.4 +/- 1.0 (open), P = 0.09]. In the group randomized to continued GH treatment almost all hormonal and metabolic parameters remained unchanged during the study. In conclusion, 1) discontinuation of GH therapy for 1 yr in adolescent patients induces fat accumulation without compromising insulin sensitivity; and 2) the beneficial effects of continued GH treatment on body composition in terms of decrease in fat mass and increase in fat-free mass does not fully balance the direct insulin antagonistic effects.

Increased levels but preserved diurnal variation of serum leptin in GH-deficient patients: lack of impact of different modes of GH administration.

The regulation of leptin production in humans is poorly understood but appears to depend on total body fat, changes in energy intake and insulin levels. Since growth hormone (GH) is an important regulator of both lipid metabolism and insulin secretion and action, we tested whether GH status directly or indirectly regulates leptin secretion. Circadian serum leptin concentrations were measured in GH-deficient patients in two different protocols involving different modes of acute and prolonged GH exposure. In study I, eight GH-deficient patients all underwent three 4 week study periods in random order: (1) evening (2000 h) s.c. GH injections (2 IU); (2) morning (0800 h) s.c. GH injections (2 IU); (3) no GH administration. At the end of each period the patients were admitted to hospital for 24-h measurements of hormones and metabolites. For comparison, 10 age- and sex-matched healthy untreated subjects were hospitalised under identical conditions. In study II, six GH-deficient patients were hospitalised for 44 h on three occasions, separated by at least 4 weeks without GH treatment. On each occasion they received 2 IU GH, administered i.v. as (1) two boluses (at 2000 and 0200 h), (2) eight boluses (at 3 h intervals starting at 2000 h) or (3) a continuous (2000-2000 h) infusion. In both studies, serum leptin levels peaked between midnight and early morning followed by low day-time levels (P < 0.01). The mode of GH treatment or previous discontinuation did not affect the leptin level (P > 0.05), but the patients had significantly higher leptin levels than the controls (P < 0.01). The diurnal variation in leptin was compared with changes in GH, insulin, non-esterified fatty acids, 3-hydroxybutyrate, insulin-like growth factor I and glucose, but no robust cross-correlations could be demonstrated. The following conclusions were made. (1) The circadian pattern of serum leptin is not influenced by either experimental or spontaneous changes in serum GH concentrations. (2) GH deficiency is associated with elevated leptin levels which most likely reflects increased fat mass in these patients.

Regulation of lipoprotein lipase and hormone-sensitive lipase activity and gene expression in adipose and muscle tissue by growth hormone treatment during weight loss in obese patients.

It is well known that growth hormone (GH) treatment reduces fat mass (FM), which presumably is mediated through stimulation of triglyceride breakdown and inhibition of adipose tissue lipoprotein lipase activity (AT-LPL). However, it is unknown which of the 2 GH-regulated pathways are of most importance for the reduction in FM. We investigated the effect of weight loss together with GH treatment on the activity and gene expression of LPL and hormone-sensitive lipase (HSL) in AT and muscle tissue. A very-low-calorie diet ([VLCD] 740 kcal/d) was given to 18 obese women (body mass index [BMI] > 35 kg/m2) and half of them were treated with GH (0.04 IU/kg) for 4 weeks in a randomized double-blind placebo-controlled study. Subcutaneous fat and muscle biopsies were taken before and after 4 weeks. Weight loss after 4 weeks was similar in the 2 groups, with a reduction of 4.5% (placebo) and 4.6% (GH) and a reduction of FM by 7.4% and 9.0% ([NS] nonsignificant). The weight loss resulted in a small and NS reduction of AT-LPL activity by 20% +/- 12% in the placebo group, but in the GH group, AT-LPL was significantly reduced by 65% +/- 8% (P < .01). Muscle LPL (M-LPL) activity was not affected by the weight loss alone, but a significant reduction was observed in the GH group (20.4% +/- 10%, P < .05). AT-HSL activity was significantly enhanced after weight loss, but GH had no additional effect on this minor increment. This is in accordance with the finding that the increment in free fatty acid (FFA) after weight loss was similar in the 2 groups. GH treatment was associated with a significant reduction of high-density lipoprotein (HDL) cholesterol (P < .05). In conclusion, GH significantly inhibited AT-LPL activity but had no additional effect on the hypocaloric-induced loss of FM, indicating that under such circumstances, AT-LPL does not directly regulate adipose tissue mass. GH was not found to have opposite effects on the activity of LPL in adipose tissue and muscle, since GH treatment reduced them both (by 65% and 20%, respectively). The VLCD-induced weight loss was associated with a minor enhanced activity of AT-HSL with no independent effect of GH. Thus, concerning body weight, FM, and lipolytic activity, treatment with GH offers no extra benefits during a VLCD for 4 weeks.

Serum leptin levels and leptin expression in growth hormone (GH)-deficient and healthy adults: influence of GH treatment, gender, and fasting.

Growth hormone (GH) treatment is associated with a reduction in fat mass in healthy and GH-deficient (GHD) subjects. This is mainly mediated via a direct GH action on adipose cells and stimulation of lipolysis. Leptin is secreted from adipose tissue and may be involved in signaling information about adipose tissue stores to the brain. Hormonal regulation of leptin is still not fully elucidated, and in the present study, we investigated both the long-term (4-month) and short-term (28-hour) GH effects on serum leptin and leptin gene expression in subcutaneous adipose tissue. In GHD adults (n = 24), leptin correlated with most estimates of adiposity (r = .62 to .86), as previously found in healthy subjects. However, no correlation was observed with intraabdominal fat determined by computed tomographic (CT) scan (INTRA-CT). GH treatment for 4 months had no independent effect on either serum leptin or leptin gene expression. In a short-term study, we found that fasting gradually reduced leptin levels in both healthy men and GHD adults, with a maximum reduction of 58% to 60% (P < .01) after 31 hours. No independent effect of GH suppression or GH substitution on serum leptin was found during fasting. Adipose tissue leptin mRNA correlated with serum leptin (r = .51, P < .01) and the body mass index ([BMI] r = .55, P < .05). Serum leptin levels and gene expression were significantly higher in women compared with men (26.6 +/- 5.8 v 10.0 +/- 1.30 ng/mL, P < .05). However, in regression analysis accounting for the gender differences in subcutaneous femoral adipose tissue (FEM-CT), the difference in serum leptin disappeared, indicating that subcutaneous femoral fat or factors closely related to femoral fat (eg, sex hormones) may be causal factors for the gender difference in leptin.

Differential effects of growth hormone and prednisolone on energy metabolism and leptin levels in humans.

Short-term growth hormone (GH) exposure has been shown to stimulate energy expenditure (EE) without concomitant changes in body composition. To what extent this is related to thyroid function, sympathetic activity, hyperinsulinemia, or leptin secretion is unknown. It is also unknown whether the calorigenic effect of GH is influenced by glucocorticoids, which are known to antagonize the anabolic actions of GH. To pursue this, eight normal male subjects (aged 22 to 28 years; body mass index, 21.6 to 26.3 kg/m2) were randomly studied during four 4-day treatment periods with (1) daily subcutaneous (SC) placebo injections and placebo tablets, (2) daily SC GH injections (0.1 IU/kg x d) and placebo tablets, (3) daily prednisolone administration (25 mg morning and evening) plus placebo injections, and (4) daily GH injections plus prednisolone administration. GH administration decreased plasma epinephrine significantly (mean +/- SE, 34.7 +/- 5.7 ng/L for control v 24.8 +/- 5.8 for GH, P < .05), had no effect on plasma norepinephrine or serum leptin, and increased both free triiodothyronine (FT3) levels (5.7 +/- 0.3 pmol/L for control v 6.7 +/- 0.3 for GH, P < .05) and resting EE ([REE] 1,861 +/- 61 kcal/24 h for control v 1,996 +/- 69 for GH, P < .05). Prednisolone administration did not affect epinephrine and REE, decreased norepinephrine (116 +/- 13, P < .05) and FT3 (4.7 +/- 0.2, P < .05), and increased leptin (3.93 +/- 0.71, P < .05). Concomitant GH and prednisolone administration increased REE (2,068 +/- 85, P +/- .05) and leptin (4.82 +/- 0.93, P +/- .05), had no effect on either epinephrine or norepinephrine, and decreased FT3 (5.0 +/- 0.2, P < .05). Resting heart rate (HR) increased only during GH, whereas sympathetic nerve activity was unchanged in all studies. Our data suggest that (1) the calorigenic effect of GH is not mediated by changes in sympathetic activity or leptin secretion, (2) rapid elevations in leptin induced by glucocorticoids do not affect EE in humans, and (3) the acute calorigenic effects of GH are probably related to increased cardiac workload.

Evidence supporting a direct suppressive effect of growth hormone on serum IGFBP-1 levels. Experimental studies in normal, obese and GH-deficient adults.

It has occasionally been suggested that GH directly suppresses circulating IGFBP-1 levels, although it is generally believed that such an effect is secondary to a GH-induced increase in insulin levels. We present data from several experiments in which the effects of GH on IGFBP-1 could be studied more extensively. In normal subjects (n = 36), an i.v. GH bolus caused a small but significant decrease in plasma IGFBP-1 concentrations without changes in insulin [IGFBP-1 (microgram/l): 2.6 +/- 0.3 (GH) vs 3.2 +/- 0.4 (placebo), P < 0.05]. Conversely, a 28-h somatostatin infusion with and without GH administration during fasting in normal subjects yielded higher IGFBP-1 levels in the non-GH substituted study [50.5 +/- 5.3 (GH-suppression) vs 22.6 +/- 5.6 (GH-substitution), P < 0.01], comparable with an increased concentration of IGFBP-1 during fasting in GH-deficient patients without usual GH substitution [23.4 +/- 7.6 (GH pause) vs 14.1 +/- 4.9 (GH substitution), P < 0.01]. In both fasting studies insulin levels remained stable. During a hypocaloric diet, long-term GH treatment in obesity lead to a significant decline in IGFBP-1 level (2.3 +/- 0.6 vs 1.2 +/- 0.2, P < 0.01), while no changes were found in the placebo group. Again, insulin levels remained equally low in both studies. Finally, a significant rebound increase in IGFBP-1 level in response to insulin induced hypoglycemia was only observed among GH-deficient patients, but not in control subjects, the latter of whom responded to hypoglycemia with a significant increase in serum GH levels [23.2 +/- 7.2 (GHDA) vs 2.5 +/- 0.3 (controls), P < 0.01]. In conclusion, a suppressive effect of GH on IGFBP-1 appears to be unmasked in the presence of low or suppressed insulin levels, making GH a potential regulator of IGF-1 bioactivity in a hitherto unrecognized way.

The growth hormone (GH)-insulin-like growth factor axis during testosterone replacement therapy in GH-treated hypopituitary males.

Several studies suggest a direct effect of sex steroids on insulin-like growth factor-I (IGF-I) production. Oestrogen has been hypothesized directly to inhibit hepatic IGF-I production, but the role of androgens is not clarified. We aimed to investigate whether testosterone exerts a pituitary-independent effect on IGF-I and related parameters. Eight adult hypopituitary men (39.9 +/- 5.7 years) receiving growth hormone (GH) and testosterone replacement therapy (250 mg testosterone enantate every fourth week) participated in this prospective study. Frequent blood samples were drawn over a 5 week period in relation to two testosterone injections. Mean baseline IGF-I levels were 352 +/- 135 microg/L, and they remained unaltered during the study period (analysis of variance (ANOVA), P = 0.88). Free IGF-I levels did not change either (ANOVA, P = 0.35). Serum IGF binding protein-3 (IGFBP-3) and acid-labile subunit decreased (ANOVA, P = 0.04 and P = 0.02 respectively) but post hoc analysis did not reveal a particular difference between days. IGFBP-1 increased following testosterone administration (ANOVA, P = 0.05), whereas GH binding protein levels tended to decrease following testosterone administration (ANOVA, P = 0.08). Prostate-specific antigen tended slightly to increase after each testosterone injection (ANOVA, P = 0.08, post hoc, NS). We conclude that major changes in total IGF-I are not induced during conventional intramuscular testosterone replacement in GH-treated hypopituitary males, suggesting that testosterone effects on IGF-I are likely to be secondary to a stimulation of endogenous GH release.

Evidence-based approach to growth hormone replacement therapy in adults, with special emphasis on body composition.

In the past decade, a large number of controlled clinical trials have reported positive effects of growth hormone (GH) replacement therapy in GH-deficient adults. The majority of these studies have been carried out in accordance with the guidelines for Good Clinical Practice. The data thus accumulated offer a solid baseline for practicing evidence-based medicine within this area of endocrinology.

[Rectal hemorrhage. Colorectal cancer and polyps in patients aged 40 and over seeking consultation]. / Haemorrhagia per rectum. Kolorektal cancer og polypper hos konsultationssøgende fra 40-års-alderen.

The objective was to determine the frequency of neoplastic conditions in patients presenting in general practice with rectal bleeding and to explain the associations between presenting symptoms and final diagnoses. We conducted two studies in which we invited Danish general practitioners to register three to four patients aged 40 and over presenting with rectal bleeding. In study 1 among 208 patients aged 40 and over and presenting with a first episode of rectal bleeding, colorectal cancer and polyps were present in 15.4 and 7.7%, respectively. In study 2 among 209 patients aged 40 and over and presenting with overt rectal bleeding, 156 reported it as either the first bleeding episode or a change in their usual bleeding pattern, and in this group colorectal cancer and polyps were diagnosed in 14.1 and 11.5% respectively. A joint analysis of the two study populations showed that only age and change in bowel habits contributed to differentiating the cancer from the non-cancer patients.

[AIDS--knowledge, behavior and attitude at the University of Aarhus in 1990. A questionnaire study]. / AIDS--viden, adfaerd og holdning på Aarhus Universitet i 1990. En spørgeskemaundersøgelse.

To describe knowledge, attitude and behaviour regarding AIDS among students and employees at the University of Aarhus an anonymous self-administered questionnaire survey was conducted in April 1990. Of the 2169 and 850 questionnaires to students and employees, respectively, 1548 (71.4%) and 568 (67%) were returned. The study group had an excellent knowledge about AIDS and the transmission of HIV-virus. However, when defining "risk behaviour" in relation to transmission of HIV-virus among heterosexuals as "> or = 2 sexual partners within the past year without using condoms" 27% of the male and 20% of the female students showed risk behaviour. Among employees the rate was highest (23%) among the male scientific staff than among the remainder (17%). It is concluded that risk behaviour was not related to age and occurred in spite of the fact that 42% of the students and 31% of the employees, who showed risk behaviour were also aware of a personal risk of being infected. There is still a need for information about AIDS, and future campaigns should be directed towards all age groups as risk behaviour is not only a phenomenon among young people.

Metabolic effects of short-term GLP-1 treatment in insulin resistant heart failure patients.

We studied the metabolic effects of 48-h GLP-1 treatment in insulin resistant heart failure patients.In a randomized placebo-controlled double-blinded cross-over study, 11 non-diabetic HF patients with IHD received 48-h GLP-1 and placebo-infusion. We applied OGTT, hyperinsulinemic clamp, indirect calorimetry, forearm, and tracer methods.7 insulin resistant HF (EF 28%±2) patients completed the protocol. GLP-1 decreased plasma glucose levels (p=0.048) and improved glucose tolerance. 4 patients had hypoglycemic events during GLP-1 vs. none during placebo. GLP-1 treatment tended to increase whole body protein turnover (p=0.08) but did not cause muscle wasting. No significant changes in circulating levels of insulin, glucagon, free fatty acids or insulin sensitivity were detected.GLP-1 treatment decreased glucose levels and increased glucose tolerance in insulin resistant HF patients with IHD. Hypoglycemia was common and may limit the use of GLP-1 in these patients. Insulin sensitivity, lipid-, and protein metabolism remained unchanged.Data were collected at the examinational laboratories of Department of Endocrinology and Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.