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L. Enk, N. Crona, J.-H. Olsson and T. Hillensjö

Abstract. Steroid production depends on the cholesterol (CH) substrate supplied by circulating lipoproteins which are internalised in the cells by receptormediated mechanisms. Low density lipoproteins (LDL) stimulate progesterone production in vitro. However, studies on follicles indicate low levels of LDL in follicular fluid (FF1).

In the present study FF1 was obtained by ultrasoundguided punctures just before ovulation from 17 women participating in an in vitro fertilization programme. Serum was obtained simultaneously. Follicular development was stimulated with hMG-HCG or clomiphenehMG-hCG combinations. In another 8 women FF1 was collected in connection with surgery for sterilization. FF1 levels of CH, triglycerides (TG), phospholipids (PL), apolipoprotein Al and B (apoAl; apoB), oestradiol and progesterone were assayed in both groups as were the corresponding serum levels in the stimulated patient group.

The FF1 levels of apoAl, TG and PL were approximately half of the levels in HDL in normal serum in both groups. However, CH was slightly lower in the stimulated group. ApoB was not detectable in FF1. Oestradiol was similar in both groups while progesterone was much higher in the stimulated than in the non-stimulated cycles. FF1 levels of apoAl correlated positively to CH and PL in both groups and to progesterone in the stimulated follicles, while the correlation was negative in the other group. The absence of apoB and the levels of CH, TG, PL and apoA1 1 indicate that high density lipoprotein (HDL), but not LDL is present in FF1. The supply of CH needed for the increased production of progesterone in the granulosa cells in the late follicular phase has to be explained by mechanisms other than transportation with LDL particles. It is possible that gonadotrophins facilitate the delivery of CH from HDL, which has been shown to penetrate the 'blood-follicle' barrier.

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B Ekman, T Lindstrom, F Nystrom, AG Olsson, G Toss and HJ Arnqvist

OBJECTIVE: To evaluate a dose titration model for recombinant human GH substitution in adult patients with GH deficiency, aiming at normal plasma levels of IGF-I. DESIGN AND METHODS: Eighteen patients participated and a start dose of 0.17 mg GH/day was used except by two men who started with 0.33 mg/day. To demonstrate a clear GH effect the patients were first titrated, with steps of 0.17 mg GH/day every 6-8 weeks, to IGF-I levels in the upper range of age-adjusted reference values. The GH dose was then reduced 1 dose step and kept for a further 6 months. For comparison we investigated 17 healthy control subjects. RESULTS: Plasma IGF-I was increased after 2 weeks on the start dose and did not increase further for up to 8 weeks. Women had significantly lower GH sensitivity than men measured as net increment of IGF-I on the start dose of GH. GH sensitivity was not changed by age. The plasma IGF-I levels increased from 76.3+/-47.0 (s.d.) to 237+/-97 microg/l at the end of the study (P<0.001), and similar IGF-I levels were obtained in both sexes. The maintenance median GH dose was 0.33 mg/day in males and 0.83 mg/day in females (P=0.017). The GH dose correlated negatively with age in both sexes. Body weight, very low density triglycerides, lipoprotein(a) (Lp(a)), and fasting insulin increased, whereas insulin sensitivity index (QUICKI) decreased significantly. In comparison with the controls, the patients had lower fasting blood glucose, fasting insulin and Lp(a) levels at baseline, but these differences disappeared after GH substitution. The two groups had equal insulin sensitivity (QUICKI), but 2 h oral glucose tolerance test values of blood glucose and insulin were significantly higher in the patients at the end of the study. CONCLUSIONS: In conclusion our data suggest that the starting dose of GH substitution and the dose titration steps should be individualised according to GH sensitivity (gender) and the IGF-I level aimed for (age). The reduced insulin sensitivity induced by GH substitution could be viewed as a normalisation if compared with control subjects.

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S Soderberg, B Ahren, M Eliasson, B Dinesen, K Brismar and T Olsson

OBJECTIVE: Hyperleptinaemia and hyperinsulinaemia interrelate to insulin-like growth factor binding protein 1 (IGFBP-1), and disturbances in the growth hormone-IGF-I axis are linked to obesity and cardiovascular diseases. However, whether the association between leptin and the GH-IGF-I axis is altered with increasing obesity is not known. We therefore examined the relationship between leptin, IGF-I, IGFBP-1, insulin and proinsulin in men and women with or without obesity in a population study. DESIGN AND SUBJECTS: Healthy subjects (n=158; 85 men and 73 pre- and postmenopausal women) from the Northern Sweden MONICA (Monitoring of Trends and Determinants in Cardiovascular Disease) population were studied with a cross-sectional design. METHODS: Anthropometric measurements (body mass index (BMI) and waist circumference) and oral glucose tolerance tests were performed. Radioimmunoassays were used for the analyses of leptin, IGF-I and IGFBP-1, and ELISAs for specific insulin and proinsulin. RESULTS: Leptin inversely correlated to IGFBP-1 in non-obese men (P<0.05) and obese postmenopausal women (P<0.05). In contrast, leptin did not correlate to IGF-I. IGFBP-1 was also significantly associated with proinsulin in non-obese men (P<0.01) and non-obese premenopausal women (P<0.05). The association between leptin and IGFBP-1 was lost after adjustment for insulin. In multivariate analyses taking measures of adiposity into account, low proinsulin, and IGF-I in combination with old age, but not leptin, predicted high IGFBP-1 levels. CONCLUSIONS: Leptin was inversely associated with IGFBP-1 in non-obese men and obese postmenopausal women, and proinsulin was inversely associated with IGFBP-1 in non-obese men and premenopausal women. However, these associations were lost with increasing central obesity in men and premenopausal women and after control for insulin. Therefore, this study suggests (i) that leptin is of minor importance for regulation of IGFBP-1 levels and (ii) that the insulin resistance syndrome is characterised by an altered relationship between leptin, IGFBP-1 and insulin.

Free access

A Johansson, T Olsson, K Cederquist, H Forsberg, JJ Holst, Seckl JR and B Ahren

OBJECTIVE: Although the incretins, gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), as well as glucagon and cortisol, are known to influence islet function, the role of these hormones in conditions of insulin resistance and development of type 2 diabetes is unknown. An interesting model for the study of hormonal perturbations accompanying marked insulin resistance without concomitant diabetes is myotonic dystrophy (DM1). DESIGN: The work was carried out in an out-patient setting. METHODS: An oral glucose tolerance test was performed in 18 males with DM1 and 18 controls to examine the release of incretins and counter-regulatory hormones. Genetic analyses were also performed in patients. RESULTS: We found that the increment in GLP-1 after oral glucose was significantly greater in patients, while there was no significant difference in GIP or glucagon responses between patients and controls, although long CTG repeat expansions were associated with a more pronounced GIP response. Interestingly, the GLP-1 response to oral glucose correlated with the insulin response in patients but not in controls whereas, in controls, the insulin response closely correlated with the GIP response. Furthermore, cortisol and ACTH levels increased paradoxically in patients after glucose; this was more pronounced in patients with long CTG repeat expansions. CONCLUSIONS: This study showed that the GLP-1 and ACTH/cortisol responses to oral glucose are abnormal in insulin-resistant DM1 patients and that CTG triplet repeats are linked to GIP release. These abnormalities may contribute both to the severe insulin resistance and hyperinsulinemia in DM1 and to the preservation of adequate islet function, enabling glucose tolerance to be normal in spite of this marked insulin resistance in DM1.

Open access

Anders H Olsson, Beatrice T Yang, Elin Hall, Jalal Taneera, Albert Salehi, Marloes Dekker Nitert and Charlotte Ling

Objective

Gene expression alterations, especially in target tissues of insulin, have been associated with type 2 diabetes (T2D). In this study, we examined if genes involved in oxidative phosphorylation (OXPHOS) show differential gene expression and DNA methylation in pancreatic islets from patients with T2D compared with non-diabetic donors.

Design and methods

Gene expression was analyzed in human pancreatic islets from 55 non-diabetic donors and nine T2D donors using microarray.

Results

While the expected number of OXPHOS genes with reduced gene expression is 7.21, we identified 21 downregulated OXPHOS genes in pancreatic islets from patients with T2D using microarray analysis. This gives a ratio of observed over expected OXPHOS genes of 26.37 by a χ 2-test with P=2.81×10−7. The microarray data was validated by qRT-PCR for four selected OXPHOS genes: NDUFA5, NDUFA10, COX11, and ATP6V1H. All four OXPHOS genes were significantly downregulated in islets from patients with T2D compared with non-diabetic donors using qRT-PCR (P≤0.01). Furthermore, HbAlc levels correlated negatively with gene expression of NDUFA5, COX11, and ATP6V1H (P<0.05). Gene expression of NDUFA5, NDUFA10, COX11, and ATP6V1H correlated positively with glucose-stimulated insulin secretion (P<0.03). Finally, DNA methylation was analyzed upstream of the transcription start for NDUFA5, COX11, and ATP6V1H. However, none of the analyzed CpG sites in the three genes showed differences in DNA methylation in islets from donors with T2D compared with non-diabetic donors.

Conclusion

Pancreatic islets from patients with T2D show decreased expression of a set of OXPHOS genes, which may lead to impaired insulin secretion.

Open access

A G Nilsson, C Marelli, D Fitts, R Bergthorsdottir, P Burman, P Dahlqvist, B Ekman, B Edén Engström, T Olsson, O Ragnarsson, M Ryberg, J Wahlberg, H Lennernäs, S Skrtic and G Johannsson

Objective

The objective was to assess the long-term safety profile of dual-release hydrocortisone (DR-HC) in patients with adrenal insufficiency (AI).

Design

Randomised, open-label, crossover trial of DR-HC or thrice-daily hydrocortisone for 3 months each (stage 1) followed by two consecutive, prospective, open-label studies of DR-HC for 6 months (stage 2) and 18 months (stage 3) at five university clinics in Sweden.

Methods

Sixty-four adults with primary AI started stage 1, and an additional 16 entered stage 3. Patients received DR-HC 20–40 mg once daily and hydrocortisone 20–40 mg divided into three daily doses (stage 1 only). Main outcome measures were adverse events (AEs) and intercurrent illness (self-reported hydrocortisone use during illness).

Results

In stage 1, patients had a median 1.5 (range, 1–9) intercurrent illness events with DR-HC and 1.0 (1–8) with thrice-daily hydrocortisone. AEs during stage 1 were not related to the cortisol exposure-time profile. The percentage of patients with one or more AEs during stage 1 (73.4% with DR-HC; 65.6% with thrice-daily hydrocortisone) decreased during stage 2, when all patients received DR-HC (51% in the first 3 months; 54% in the second 3 months). In stages 1–3 combined, 19 patients experienced 27 serious AEs, equating to 18.6 serious AEs/100 patient-years of DR-HC exposure.

Conclusions

This long-term prospective trial is the first to document the safety of DR-HC in patients with primary AI and demonstrates that such treatment is well tolerated during 24 consecutive months of therapy.