R Pasquali and M Filicori
R. Pasquali, P. Buratti, F. Casimirri, D. Patrono, M. Capelli, N. Melchionda, and L. Barbara
Abstract. The aim of the study was to evaluate the reliability of urinary excretion rate of C-peptide as a marker of B-cell function during fasting. Ten obese subjects of both sexes fasted for 5 days. Diurnal serum C-peptide was collected before and on the 5th day; morning serum samples (for glucose, insulin and C-peptide) and 12-h urine samples (7.00 to 19.00 h) were collected daily. Body weight decreased from 138.7 ± 15.9 to 132.9 ± 15.6 kg. Morning glucose, insulin (–40%) and C-peptide (–50%) fell significantly throughout the study. Mean diurnal C-peptide values were 2.19 ±0.69 nmol/l before and 0.60 ±0.19 nmol/l after fasting (P < 0.0001) and its secretion rate was 909.4 ± 297.9 and 244.4 ± 83.9 nmol/12 h (P < 0.005), respectively. Excretion rate of C-peptide fell progressively from basal (11.2 ± 4.2 nmol/12 h) to a nadir value of 1.3 ± 0.8 nmol/12 h (P < 0.0005); similarly, the C-peptide to creatinine clearance ratio fell from 0.062 ± 0.035 to 0.028 ± 0.015 (P < 0.05). These results indicate that fasting modifies renal metabolism of C-peptide thus creating several complications in the quantitative interpretation of urinary levels as an index of its secretion rate from the B-cell.
Alessandra Gambineri, Flaminia Fanelli, Federica Tomassoni, Alessandra Munarini, Uberto Pagotto, Ruth Andrew, Brian R Walker, and Renato Pasquali
Abnormal cortisol metabolism in polycystic ovary syndrome (PCOS) has been invoked as a cause of secondary activation of the hypothalamic–pituitary–adrenal axis and hence androgen excess. However, this is based on urinary excretion of cortisol metabolites, which cannot detect tissue-specific changes in metabolism and may be confounded by obesity.
To assess cortisol clearance and whole-body and tissue-specific activities of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1 (HSD11B1)) in PCOS.
A total of 20 overweight–obese unmedicated Caucasian women with PCOS, aged 18–45 years, and 20 Caucasian controls matched for age, BMI, body fat distribution, and HSD11B1 genotypes (rs846910 and rs12086634).
Main outcome measures
Cortisol metabolites were measured in 24 h urine. During steady-state 9,11,12,12-[2H]4-cortisol infusion, cortisol clearance was calculated and whole-body HSD11B1 activity was assessed as the rate of appearance of 9,12,12-2H3-cortisol (d3-cortisol). Hepatic HSD11B1 activity was quantified as the generation of plasma cortisol following an oral dose of cortisone. Subcutaneous adipose HSD11B1 activity and HSD11B1 mRNA were measured, ex vivo, in biopsies.
Urinary cortisol metabolite excretion, deuterated cortisol clearance, and the rate of appearance of d3-cortisol did not differ between patients with PCOS and controls. However, hepatic HSD11B1 conversion of oral cortisone to cortisol was impaired (P<0.05), whereas subcutaneous abdominal adipose tissue HSD11B1 mRNA levels and activity were increased (P<0.05) in women with PCOS when compared with controls.
Tissue-specific dysregulation of HSD11B1 is a feature of PCOS, over and above obesity, whereas increased clearance of cortisol may result from obesity rather than PCOS.
A Gambineri, R K Semple, G Forlani, S Genghini, I Grassi, C S S Hyden, U Pagotto, S O'Rahilly, and R Pasquali
Despite the very high prevalence of the polycystic ovary syndrome (PCOS), the underlying pathogenetic mechanism has remained obscure.
To determine the cause of two sisters' PCOS associated with severe insulin resistance.
Clinical case report.
Two sisters who presented with hyperandrogenism and menstrual disorders in the context of PCOS, and were subsequently found to be severely insulin resistant. Physical examination revealed muscular hypertrophy with a paucity of fat in the extremities, trunk and gluteal regions, in spite of excess fat deposits in the face, neck and dorsocervical region. Known genes involved in familial partial lipodystrophy were screened. At the same time, metformin (1700 mg/day) was commenced. After 2–3 years of uninterrupted therapy, lack of clinical improvement led to the introduction of pioglitazone (30 mg/day).
Both sisters were found to be heterozygous for the R482Q mutation in the lamin A/C gene (LMNA) gene, establishing the definitive diagnosis as Dunnigan-type familial partial lipodystrophy complicated by severe insulin resistance and secondary PCOS. Treatment with pioglitazone resulted in progressive amelioration of insulin resistance, hyperinsulinaemia and hyperandrogenaemia. Menses also improved, with restoration of a eumenorrhoeic pattern, and the framework of ultrasound PCO was in complete remission.
Assessment of insulin sensitivity and adipose tissue topography should be a key part of the initial evaluation of patients with PCOS. Identifying such forms of PCOS with monogenic insulin resistance as the primary pathogenic abnormality may have practical implications for therapy, since they respond to thiazolidinediones, but not to metformin.
Alessandra Gambineri, Federica Tomassoni, Alessandra Munarini, Roland H Stimson, Roberto Mioni, Uberto Pagotto, Karen E Chapman, Ruth Andrew, Vilma Mantovani, Renato Pasquali, and Brian R Walker
Regeneration of cortisol by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) within liver and adipose tissue may be of pathophysiological importance in obesity and the metabolic syndrome. single nucleotide polymorphisms (SNPs) in HSD11B1, the gene encoding 11β-HSD1, have been associated with type 2 diabetes and hypertension in population-based cohort studies, and with hyperandrogenism in patients with the polycystic ovary syndrome (PCOS). However, the functional consequences of these SNPs for in vivo 11β-HSD1 expression and activity are unknown.
We explored associations of well-characterised hormonal and metabolic phenotypes with two common SNPs (rs846910 and rs12086634) in HSD11B1 in 600 women (300 with PCOS) and investigated 11β-HSD1 expression and activity in a nested study of 40 women from this cohort.
HSD11B1 genotypes (as single SNPs and as the combination of the two minor allele SNPs) were not associated with PCOS. Women who were heterozygous for rs846910 A and homozygous for rs12086634 T (GA, TT genotype) had a higher risk of metabolic syndrome, regardless of the diagnosis of PCOS (odds ratio in the whole cohort=2.77 (95% confidence interval (CI) 1.16–6.67), P=0.023). In the nested cohort, women with the GA, TT genotype had higher HSD11B1 mRNA levels in adipose tissue, and higher rates of appearance of cortisol and d3-cortisol (16.1±0.7 nmol/min versus 12.1±1.1, P=0.044) during 9,11,12,12-2H4-cortisol (d4-cortisol) steady-state infusion.
We conclude that, in a population of Southern European Caucasian women with and without PCOS, alleles of HSD11B1 containing the two SNPs rs846910 A and rs12086634 T confer increased 11β-HSD1 expression and activity, which associates with the metabolic syndrome.
S Belli, D Santi, E Leoni, E Dall’Olio, F Fanelli, M Mezzullo, C Pelusi, L Roli, S Tagliavini, T Trenti, A R Granata, U Pagotto, R Pasquali, V Rochira, C Carani, and M Simoni
Men with Klinefelter syndrome (KS) show hypergonadotropic hypogonadism, but the pathogenesis of hypotestosteronemia remains unclear. Testicular steroidogenesis in KS men was evaluated over three decades ago after human chorionic gonadotropin (hCG) stimulation, but inconclusive results were obtained. Intriguingly, some recent studies show increased intratesticular testosterone concentrations in men with KS.
To analyze serum steroid profile, as a proxy of testicular steroidogenesis, after hCG stimulation in KS compared with control men.
A prospective, longitudinal, case–control, clinical trial.
Thirteen KS patients (36±9 years) not receiving testosterone (TS) replacement therapy and 12 eugonadic controls (32±8 years) were enrolled. Serum steroids were measured by liquid chromatography–tandem mass spectrometry (LC–MS/MS) at baseline and for five consecutive days after intramuscular injection of 5000IU hCG.
Progesterone (P), 17-hydroxyprogesterone (17OHP), TS, and estradiol (E2) showed a significant increase (P<0.001) after hCG stimulation in both groups. On the contrary, androstenedione (AS) and dehydroepiandrosterone did not increase after hCG stimulation. The 17OHP/P ratio increased in both groups (P<0.001), the TS/AS ratio (17β-hydroxysteroid dehydrogenase type 3 (17βHSD3) activity) did not increase after hCG in any group, and the E2/TS ratio (aromatase activity) increased significantly in both groups (P=0.009 in KS and P<0.001 in controls). Luteinizing hormone decreased after hCG in both groups (P=0.014 in KS and P<0.001 in controls), whereas follicle-stimulating hormone decreased only in control men (P<0.001).
This study demonstrates for the first time using LC–MS/MS that Leydig cells of KS men are able to respond to hCG stimulation and that the first steps of steroidogenesis are fully functional. However, the TS production in KS men is impaired, possibly related to reduced hydroxysteroid deydrogenase activity due to an unfavorable intratesticular metabolic state.
R Pasquali, F Casanueva, M Haluzik, L van Hulsteijn, S Ledoux, M P Monteiro, J Salvador, F Santini, H Toplak, and O M Dekkers
Obesity is an emerging condition, with a prevalence of ~20%. Although the simple measurement of BMI is likely a simplistic approach to obesity, BMI is easily calculated, and there are currently no data showing that more sophisticated methods are more useful to guide the endocrine work-up in obesity. An increased BMI leads to a number of hormonal changes. Additionally, concomitant hormonal diseases can be present in obesity and have to be properly diagnosed – which in turn might be more difficult due to alterations caused by body fatness itself. The present European Society of Endocrinology Clinical Guideline on the Endocrine Work-up in Obesity acknowledges the increased prevalence of many endocrine conditions in obesity. It is recommended to test all patients with obesity for thyroid function, given the high prevalence of hypothyroidism in obesity. For hypercortisolism, male hypogonadism and female gonadal dysfunction, hormonal testing is only recommended if case of clinical suspicion of an underlying endocrine disorder. The guideline underlines that weight loss in obesity should be emphasized as key to restoration of hormonal imbalances and that treatment and that the effect of treating endocrine disorders on weight loss is only modest.
L T van Hulsteijn, R Pasquali, F Casanueva, M Haluzik, S Ledoux, M P Monteiro, J Salvador, F Santini, H Toplak, and O M Dekkers
The increasing prevalence of obesity is expected to promote the demand for endocrine testing. To facilitate evidence guided testing, we aimed to assess the prevalence of endocrine disorders in patients with obesity. The review was carried out as part of the Endocrine Work-up for the Obesity Guideline of the European Society of Endocrinology.
Systematic review and meta-analysis of the literature.
A search was performed in MEDLINE, EMBASE, Web of Science and COCHRANE Library for original articles assessing the prevalence of hypothyroidism, hypercortisolism, hypogonadism (males) or hyperandrogenism (females) in patients with obesity. Data were pooled in a random-effects logistic regression model and reported with 95% confidence intervals (95% CI).
Sixty-eight studies were included, concerning a total of 19.996 patients with obesity. The pooled prevalence of overt (newly diagnosed or already treated) and subclinical hypothyroidism was 14.0% (95% CI: 9.7–18.9) and 14.6% (95% CI: 9.2–20.9), respectively. Pooled prevalence of hypercortisolism was 0.9% (95% CI: 0.3–1.6). Pooled prevalence of hypogonadism when measuring total testosterone or free testosterone was 42.8% (95% CI: 37.6–48.0) and 32.7% (95% CI: 23.1–43.0), respectively. Heterogeneity was high for all analyses.
The prevalence of endocrine disorders in patients with obesity is considerable, although the underlying mechanisms are complex. Given the cross-sectional design of the studies included, no formal distinction between endocrine causes and consequences of obesity could be made.