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Free access

Mette L Nielsen, Manan Pareek, Margrét Leósdóttir, Karl-Fredrik Eriksson, Peter M Nilsson, and Michael H Olsen

Objective

To examine the predictive capability of a 1-h vs 2-h postload glucose value for cardiovascular morbidity and mortality.

Design

Prospective, population-based cohort study (Malmö Preventive Project) with subject inclusion 1974–1992.

Methods

4934 men without known diabetes and cardiovascular disease, who had blood glucose (BG) measured at 0, 20, 40, 60, 90 and 120 min during an OGTT (30 g glucose per m2 body surface area), were followed for 27 years. Data on cardiovascular events and death were obtained through national and local registries. Predictive capabilities of fasting BG (FBG) and glucose values obtained during OGTT alone and added to a clinical prediction model comprising traditional cardiovascular risk factors were assessed using Harrell’s concordance index (C-index) and integrated discrimination improvement (IDI).

Results

Median age was 48 (25th–75th percentile: 48–49) years and mean FBG 4.6 ± 0.6 mmol/L. FBG and 2-h postload BG did not independently predict cardiovascular events or death. Conversely, 1-h postload BG predicted cardiovascular morbidity and mortality and remained an independent predictor of cardiovascular death (HR: 1.09, 95% CI: 1.01–1.17, P = 0.02) and all-cause mortality (HR: 1.10, 95% CI: 1.05–1.16, P < 0.0001) after adjusting for various traditional risk factors. Clinical risk factors with added 1-h postload BG performed better than clinical risk factors alone, in predicting cardiovascular death (likelihood-ratio test, P = 0.02) and all-cause mortality (likelihood-ratio test, P = 0.0001; significant IDI, P = 0.0003).

Conclusion

Among men without known diabetes, addition of 1-h BG, but not FBG or 2-h BG, to clinical risk factors provided incremental prognostic yield for prediction of cardiovascular death and all-cause mortality.

Free access

Camilo Jimenez, Pia Burman, Roger Abs, David R Clemmons, William M Drake, Kent R Hutson, Michael Messig, Michael O Thorner, Peter J Trainer, and Robert F Gagel

Objective

We examined pituitary tumor volumes in patients treated with pegvisomant for 18 months or longer, and in whom the tumors were monitored for at least 3 years. We present details on 9 of 304 patients in clinical trials with pegvisomant who experienced tumor growth within the first year of treatment.

Method

Magnetic resonance images prior to start of pegvisomant and at last follow-up were examined in 43 patients (14% of participating patients). Twenty-nine had received prior radiation therapy (18% of irradiated patients) and all but five received somatostatin analogs between periods of pegvisomant treatment.

Results

At follow-up, the median tumor volume was 0.6 cc (range 0.0–19.7 cc), in comparison with 1.6 cc (0.0–19.7 cc) at baseline (P<0.001). Twenty-five patients, of which 23 received radiation therapy, had tumor volume reduction. Seventeen patients had no significant change. One patient, who had not received radiation therapy, had an increase in tumor volume from 1.61 to 1.93 cc. Of the nine patients with tumor growth, six had progressive growth before initiating pegvisomant. Two patients with stable tumors while on octreotide experienced enlargement after octreotide discontinuation but remained stable on long-term pegvisomant therapy.

Conclusion

The present data indicate that pegvisomant does not promote tumor growth and suggest that the nine observed cases of tumor progression, which occurred within 8 months after commencing pegvisomant, are likely rebound expansions after discontinuation of somatostatin analogs and/or the natural history of aggressively growing pituitary tumors. Continued long-term surveillance of tumor volume, particularly in non-irradiated patients, is recommended.

Restricted access

Márta Korbonits, Peter J Trainer, Giuseppe Fanciulli, Osvaldo Oliva, Alessandra Pala, Alessandra Dettori, Michael Besser, Giuseppe Delitala, and Ashley B Grossman

Korbonits M, Trainer PJ, Fanciulli G, Oliva O, Pala A, Dettori A, Besser GM, Delitala G, Grossman AB. l-Arginine is unlikely to exert neuroendocrine effects in humans via the generation of nitric oxide. Eur J Endocrinol 1996;135:543–7. ISSN 0804–4643

There is now considerable evidence that nitric oxide is an important neuroregulatory agent, but there has been very little investigation of its possible role in neuroendocrine mechanisms in humans. We have investigated the effects of two nitric oxide precursors, l-arginine and molsidomine, under basal conditions on the pituitary hormones growth hormone (GH), prolactin, luteinizing hormone, folliclestimulating hormone, thyrotrophin, adrenocorticotrophin (ACTH) and vasopressin, and also on serum cortisol; we have also studied the effect of l-arginine on circulating prolactin, ACTH and cortisol in normal human subjects under hypoglycaemic stress. l-Arginine stimulated both GH and prolactin release under basal conditions but had no effect on the other hormones studied, while the nitric oxide donor molsidomine showed no effect on any hormone studied. l-Arginine potentiated the hypoglycaemia-stimulated release of ACTH but did not influence the rise in GH. The current studies suggest that the effects of l-arginine on the stimulation of GH and prolactin release are unlikely to be mediated via the generation of nitric oxide.

A Grossman, Department of Endocrinology, St Bartholomew's Hospital, West Smithfield, London EC1A 7BE, UK

Free access

Mette Lundgren Nielsen, Manan Pareek, Margrét Leósdóttir, Kurt Højlund, Karl-Fredrik Eriksson, Peter M Nilsson, and Michael Hecht Olsen

Abstract

Objective

To examine the impact of follow-up duration on the incremental prognostic yield of a baseline oral glucose tolerance test (OGTT) for predicting type 2 diabetes and to assess the discrimination ability of blood glucose (BG) obtained at different time points during OGTT.

Design

A prospective, population-based cohort study (Malmö Preventive Project) with inclusion of subjects from 1974 to 1992.

Methods

A total of 5256 men without diabetes, who had BG measured at 0, 20, 40, 60, 90, and 120 min during OGTT (30 g/m2 glucose), were followed for 30 years. Incident type 2 diabetes was recorded using registries. The performance of OGTT added to a clinical prediction model (age, body mass index (BMI), diastolic blood pressure, fasting BG, triglycerides, and family history of diabetes) was assessed using Harrell’s concordance index (C-index) and integrated discrimination improvement (IDI).

Results

Median age was 48 years, mean BMI 24.9 kg/m2, and mean fasting BG 4.7 mmol/L. Models with added post-load BG performed better than the clinical model (C-index: P = 0.08 for BG at 120 min at 5 years, otherwise P ≤ 0.045; IDI: P ≥ 0.06 for BG at 60 and 90 min at 5 years, otherwise P ≤ 0.01). With a longer follow-up duration, C-index decreased, and the C-index increase associated with OGTT was attenuated. Models including BG at 60 or 90 min performed significantly better than the model with BG at 120 min, evident beyond follow-up of 10 and 5 years, respectively.

Conclusions

OGTT provided incremental prognostic yield for type 2 diabetes prediction. BG measured at 60 or 90 min provided better discrimination than BG at 120 min.

Restricted access

Michael C. Sheppard, Clifford J. Bailey, Peter R. Flatt, Sara K. Swanston-Flatt, and Kathleen I.J. Shennan

Abstract. Immunoreactive neurotensin was measured in plasma and acid-ethanol extracts of brain, intestine and pancreas of obese hyperglycaemic (ob/ob) mice of the Aston strain, C57BL/KsJ diabetes-obese (db/db) mice, and their respective lean controls. In lean mice, the intestine was the major source of neurotensin (156–194 ng/g wet weight and 169–361 ng/intestine), with smaller amounts in the brain (33–43 ng/g and 13–17 ng/brain), pancreas (0.8–1.1 ng/g and 0.28–0.32 ng/pancreas) and plasma (50–100 pg/ml). Compared with lean controls, ob/ob and db/db mice exhibited 13 and 23% decreases in brain weight, and 37 and 82% increases in intestinal weight. Concentrations of neurotensin in plasma and brain were similar in lean and obese-diabetic mutant mice, but the total content of brain neurotensin was 25% lower in ob/ob mice. Neurotensin was unchanged in the pancreas of db/db mice. However, raised concentrations and total contents of neurotensin were observed in the pancreas of ob/ob mice (72 and 57%, respectively) and the intestine of both ob/ob (56 and 118%) and db/db (35 and 144%) mice. These observations raise the possibility that increased neurotensin concentrations might exert local effects in the intestine and pancreas which contribute to the pathogenesis of obesity-diabetes syndromes in mice.

Open access

Simon Kayemba-Kay's, Michael P P Geary, Jane Pringle, Charles H Rodeck, John C P Kingdom, and Peter C Hindmarsh

Background

Low birth weight (BW), small head circumference, reduced length, increased preterm births and neuro-endocrine dysfunctions are among known consequences of smoking during pregnancy. Few studies have linked leptin to clinical features of growth restriction associated with maternal smoking and explored interaction with other determinants of size at birth, such as gender.

Methods

Cord serum leptin concentrations were measured in 1215 term infants born to Caucasian mothers at completion of uneventful pregnancy. Serum concentrations were related to BW, gestational length, gender and maternal smoking and interaction with other determinants of size at birth evaluated.

Results

Smoking was more frequent in younger (P<0.001) and shorter mothers (P=0.03) from lower socio-economic groups (SEGPs) (P<0.001). Infants born to smokers were lighter (190 g less), shorter and with smaller head circumference. Cord serum leptin concentrations were higher in girls (9.8 s.d. 7.6 ng/ml) than in boys (7.05 s.d. 5.8 ng/ml) (P<0.001). Boys were heavier (BW 3.52 s.d. 0.49 kg) than girls (3.39 s.d. 0.44 kg) (P<0.001), but girls had greater skinfold thickness measurements (sub-scapular and quadriceps skinfold thicknesses 5.5 s.d. 1.6 mm and 7.6 s.d. 1.9 mm respectively; boys 5.3 s.d. 1.6 vs 7.24±1.90 mm, P<0.001 respectively). Multivariate analyses showed gender (P<0.001), BW SDS (P<0.001), gestational length (P<0.001) and maternal smoking (P<0.042) as factors that influenced umbilical cord serum leptin concentrations in newborns.

Conclusion

Maternal smoking restrains foetal growth through placental vascular effects, and likely also via associated effects on leptin metabolism. More studies are needed to determine the influence that maternal smoking may have on placental syncytiotrophoblast and foetal adipose tissue.

Open access

Vasileios Chortis, Nicholas J Johal, Irina Bancos, Matthew Evans, Kassiani Skordilis, Peter Guest, Michael H Cullen, Emilio Porfiri, and Wiebke Arlt

Mitotane (o,p′DDD) is established in the adjuvant and advanced-stage treatment of adrenocortical carcinoma and counteracts both tumor growth and tumor-related steroid production. Both the adrenal glands and the gonads are steroidogenically active organs and share a common embryogenic origin. Here, we describe the effects of mitotane in two patients with metastatic Leydig cell tumor (LCT) of the testes and associated severe androgen excess (serum testosterone 93 and 88 nmol/L, respectively; male reference range 7–27 nmol/L). Both men suffered from severe restlessness, insomnia and irritability, which they described as intolerable and disrupting normal life activities. Urinary steroid profiling by gas chromatography–mass spectrometry (GC–MS) confirmed excess androgen production and revealed concurrent overproduction of glucocorticoids and glucocorticoid precursors, which under physiological conditions are produced only by the adrenal glands but not by the gonads. In a palliative approach, they were commenced on mitotane, which achieved swift control of the hormone excess and the debilitating clinical symptoms, restoring normal quality of life. GC–MS demonstrated normalization of steroid production and decreased 5α-reductase activity, resulting in decreased androgen activation, and imaging demonstrated disease stabilization for 4–10 months. In conclusion, mitotane can be highly effective in controlling steroid excess in metastatic LCTs, with anti-tumor activity in some cases.

Free access

Andreas Oberbach, Stefanie Lehmann, Katharina Kirsch, Joanna Krist, Melanie Sonnabend, Axel Linke, Anke Tönjes, Michael Stumvoll, Matthias Blüher, and Peter Kovacs

Objective

Exercise training has been shown to have anti-inflammatory effects in patients with type 2 diabetes. Changes in interleukin-6 (IL-6) serum concentrations in response to training could contribute to these beneficial effects. However, there are heterogeneous data on whether circulating IL-6 is altered by exercise training. We therefore hypothesize that genetic factors modify the individual changes in IL-6 levels after long-term training.

Research design and methods

The −174G/C variant in the IL-6 gene was genotyped in 60 subjects with impaired glucose tolerance. For a 12-month interventional study, patients were randomized into three groups: a control group (n=16) was compared with one group, which underwent a standardized training program (n=24) and another group, which was treated with 4 mg rosiglitazone once daily (n=20). At baseline, after 1, 6, and 12 months, we measured anthropometric parameters and serum concentration of IL-6 and, at baseline and after 12 months, we determined glucose tolerance and fitness level.

Results

Only in subjects carrying the SNP −174C allele did long-term exercise training result in significantly reduced IL-6 serum concentrations. Multivariate linear regression analysis identified the IL-6 genotype as a significant predictor of changes in IL-6 serum concentrations independent of age, gender and improvement in body mass index, hemoglobin (Hb)A1c, and fitness level in response to training.

Conclusions

Genetic variants in the IL-6 gene significantly modify changes in IL-6 serum concentrations in response to long-term exercise training programs. Our data suggest that genetic factors are important determinants for the individual response to anti-inflammatory effects of exercise training.

Free access

Simon Kayemba-Kay's, Catherine Peters, Michael P P Geary, Nathan R Hill, David R Mathews, and Peter C Hindmarsh

Objective

To evaluate the relationships across a range of glucose and insulin measures at 12 weeks of gestation with the development of pregnancy-induced hypertension (PIH), gestational diabetes mellitus (GDM) and birth size.

Materials and methods

Prospective study of pregnant women booking before 15th week of gestation. At the first antenatal visit, standard measures of height, weight, blood pressure (BP) and social status were recorded, and blood sample was drawn for measurements of fasting glucose and plasma insulin. Oral glucose tolerance test with 75 g glucose load was performed after overnight fast. Odds ratios (ORs) with 95% CI were calculated to determine the risk of developing PIH or GDM depending on quartiles of blood glucose or tertiles of plasma insulin levels.

Results

One thousand six hundred and fifty pregnant women were included in the study. Of them, 1484 delivered a live infant of whom 70 were preterm, 166 did not complete the study, 155 mothers developed PIH (10.4%), 18 were diagnosed with GDM (1.2%) and four had both PIH and GDM. At 12 weeks of gestation, women who became hypertensive were heavier (P<0.001), with higher BMI (P<0.001) than controls. Both systolic (P<0.001) and diastolic BPs (P<0.001) were already higher in women who developed PIH. Fasting insulin concentrations were higher in PIH group (P<0.002). Fasting glucose level >6.8 mmol/l was associated with the likelihood of delivering a macrosomic baby (OR 3.1 (95% CI: 1.21–8.0); P=0.02); the effect was heightened in multiparous mothers (OR 4.0 (95% CI: 1.4–11.1); P=0.01). Fasting plasma insulin had, however, no effect on size at birth in this study.

Conclusions

Our data suggest that women who develop PIH may be metabolically challenged at early stages of pregnancy with hyperinsulinism, insulin insensitivity and slightly higher BP.

Open access

Martin Wabitsch, Lutz Pridzun, Michael Ranke, Julia von Schnurbein, Anja Moss, Stephanie Brandt, Katja Kohlsdorf, Barbara Moepps, Michael Schaab, Jan-Bernd Funcke, Peter Gierschik, Pamela Fischer-Posovszky, Bertram Flehmig, and Jürgen Kratzsch

Context and aims

Functional leptin deficiency is characterized by high levels of circulating immunoreactive leptin (irLep), but a reduced bioactivity of the hormone due to defective receptor binding. As a result of the fact that affected patients can be successfully treated with metreleptin, it was aimed to develop and validate a diagnostic tool to detect functional leptin deficiency.

Methods

An immunoassay capable of recognizing the functionally relevant receptor-binding complex with leptin was developed (bioLep). The analytical quality of bioLep was validated and compared to a conventional assay for immune-reactive leptin (irLep). Its clinical relevance was evaluated in a cohort of lean and obese children and adults as well as in children diagnosed with functional leptin deficiency and their parents.

Results

In the clinical cohort, a bioLep/irLep ratio of 1.07 (range: 0.80–1.41) was observed. Serum of patients with non-functional leptin due to homozygous amino acid exchanges (D100Y or N103K) revealed high irLep but non-detectable bioLep levels. Upon treatment of these patients with metreleptin, irLep levels decreased, whereas levels of bioLep increased continuously. In patient relatives with heterozygous amino acid exchanges, a bioLep/irLep ratio of 0.52 (range: 0.48–0.55) being distinct from normal was observed.

Conclusions

The new bioLep assay is able to diagnose impaired leptin bioactivity in severely obese patients with a homozygous gene defect and in heterozygous carriers of such mutations. The assay serves as a diagnostic tool to monitor leptin bioactivity during treatment of these patients.