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M Pugeat

Publications and source records attributed to M Pugeat.

At least 19 recordsLinked to original sources
PubMed2006

Reproductive outcome of women with 21-hydroxylase-deficient nonclassic adrenal hyperplasia.

CONTEXT: Because many women with 21-hydroxylase (21-OH)-deficient nonclassic adrenal hyperplasia (NCAH) carry at least one allele affected by a severe mutation of CYP21, they are at risk for giving birth to infants with classic adrenal hyperplasia (CAH). OBJECTIVE: Our objective was to determine the frequency of CAH and NCAH infants born to mothers with 21-OH-deficient NCAH. DESIGN AND SETTING: We conducted an international multicenter retrospective/prospective study. PATIENTS AND METHODS: The outcome of 203 pregnancies among 101 women with 21-OH-deficient NCAH was reviewed. The diagnosis of 21-OH-deficient NCAH was established by a basal or post-ACTH-stimulation 17-hydroxyprogesterone level of more than 10 ng/ml (30.3 nmol/liter). When possible, genotype analyses were performed to confirm CAH or NCAH in the offspring. RESULTS: Of the 203 pregnancies, 138 (68%) occurred before the mother's diagnosis of NCAH and 65 (32%) after the diagnosis. Spontaneous miscarriages occurred in 35 of 138 pregnancies (25.4%) before the maternal diagnosis of NCAH, and in only four of 65 pregnancies (6.2%) after the diagnosis (P < 0.002). Four (2.5%; 95% confidence interval, 0.7-6.2%) of the 162 live births were diagnosed with CAH. To date, 24 (14.8%; 95% confidence interval, 9.0-20.6%) children, 13 girls and 11 boys, have been diagnosed with NCAH. The distribution of NCAH children and their mothers varied significantly by ethnicity (P < 0.0001, for both). CONCLUSIONS: The risk of a mother with 21-OH-deficient NCAH for giving birth to a child affected with CAH is 2.5%; at least 14.8% of children born to these mothers have NCAH.

Adrenal Hyperplasia, Congenital↗
PubMed2004

Advances in growth hormone therapy: a new registry tool.

Growth hormone (GH) deficiency is a rare condition, and physicians may lack clinical experience of its treatment. Despite evidence for the efficacy and tolerability of GH therapy, a substantial proportion of patients remain untreated. Registries and other large-scale databases are an important tool for expanding the evidence base for GH treatment. Since the mid-1980s, registries have provided data on important aspects of the safety and efficacy of GH treatment. Registries have also allowed pooling of data from patients with rare conditions that could otherwise not be recruited in sufficient numbers for clinical trials. Importantly for patients and their relatives, use of registry data has allowed the development of prediction models that indicate the likely outcomes of treatment. MEGHA (Metabolic Endocrinology and Growth Hormone Assessment) is a recently developed, observational database with a number of features not found in existing registries, including its use as a day-to-day clinical management tool, the ability to create individual sub-studies, direct comparison of personal data against the full database, and a particular focus on the transition from childhood to adulthood. This creative registry is a promising instrument for further research into GH-related disorders that will improve GH therapy and thus provide benefits for patients.

Endocrinology↗
PubMed2003

[Contribution of bioavailable testosterone assay for the diagnosis of androgen deficiency in elderly men].

With age, some men develop symptoms resembling hypogonadism. Several cross-sectional and longitudinal studies have shown a decrease in testosterone levels with ageing in men. This finding has equally been observed in elderly men in good health. Testosterone levels decline progressively as of the thirties, at a rate which remains constant throughout life. While total testosterone levels decrease, sex hormone binding globulin (SHBG) levels on the contrary increase with age, with the result that the levels of free and non-SHBG-bound testosterone (corresponding to the fraction which is bioavailable to target cells) decrease more abruptly than that of total testosterone. Higher LH levels, decreased testosterone response to hCG and less Leydig cells all indicate that ageing induces partial testicular failure. However, the gonadotropic function is also affected in ageing. The hypothalamus-pituitary becomes more sensitive to gonad steroid feedback, LH pulse amplitude decreases, and the LH response to GnRH is blunted compared to the situation in young men. Thus LH level is not a valid index of androgen deficiency in elderly males. None of the androgen-dependent functions (libido, erection, sense of well-being, muscle mass and strength, fat mass, bone mass, erythropoiesis, etc.) are under exclusively androgen control, and there is no elderly male symptom which is completely specific to androgen deficiency. Thus, in elderly men, when clinical symptoms might indicate androgen deficiency, biological confirmation is needed. An assay which is independent of SHBG fluctuations is mandatory. Bioavailable testosterone assay by ammonium sulfate precipitation seems to us to be the optimum method for diagnosing androgen deficiency: it gives a reliable measurement for the testosterone fraction available to target cells, is adapted to clinical practice, and provides results that can be directly compared with current reference values for healthy young men.

Adult↗
PubMed2002

Sex hormone-binding globulin levels and cardiovascular risk factors in morbidly obese subjects before and after weight reduction induced by diet or malabsorptive surgery.

One of the main goals of weight reduction in morbidly obese subjects is its benefit on coronary heart disease (CHD) risk. A cross-sectional study was designed to randomly assign 79 morbidly obese subjects (27 men and 52 women; age: 30-45 years) either to a diet protocol (20 kcal per kg fat-free mass (FFM); 55% carbohydrates, 30% fat, and 15% proteins) or to malabsorptive surgery (biliopancreatic diversion). Fatness parameters, measured by dual-energy X-ray absorptiometry, lipid profile, insulin, leptin, sex steroid hormones and sex hormone-binding globulin (SHBG) levels were compared at baseline and 1 year after the beginning of the study. The data showed that plasma SHBG levels, but not testosterone levels, correlated negatively to fasting insulin levels and positively to HDL-cholesterol in both men and women. Total leptin levels were significantly lower (P<0.0001) in post-BPD subjects of both sexes compared to dietary treated obese subjects. The logarithm of plasma leptin correlated significantly and positively with insulin but negatively with SHBG.A step-down regression analysis showed that FFM and SHBG, but not insulin levels, were the most powerful independent variables for predicting HDL-cholesterol levels in morbidly obese patients. The negative relationship between SHBG levels and CHD risk appears to be mediated by a concomitant variation in body fatness. Finally, in obese patients, SHBG levels seem to be an indicator of total adiposity rather than an index of an altered insulin/glucose homeostasis.

Adult↗
PubMed2001

Study of the effect of changing glucose, insulin, and insulin-like growth factor-I levels on serum corticosteroid binding globulin in lean, obese, and obese subjects with glucose intolerance.

We have previously described that serum corticosteroid binding globulin (CBG) concentrations are associated with insulin secretion. The present study was designed to evaluate the effects of changing insulin concentrations, both endogenous and after exogenous insulin administration, on circulating CBG levels in vivo. Serum CBG concentrations were measured during an insulin-modified frequently sampled intravenous (IV) glucose tolerance test (FSIVGT) in 14 lean and 19 obese otherwise healthy subjects with varying degrees of glucose tolerance. Acute insulin response to glucose (AIRg) correlated significantly with serum CBG concentrations at time 0 (r = -.38, P =.029), 22 minutes (r = -.41, P =.01), 50 minutes (r = -.41, P =.01), and 180 minutes (r = -.39, P =.02). Insulin sensitivity (S(I)) was not associated with serum CBG concentration at time 0 (r = -.16, P = not significant [NS]), but correlated significantly with CBG concentration at 22 minutes (r = -.41, P =.02) and 50 minutes (r = -.35, P =.048) of the FSIVGT. In lean subjects, serum CBG concentration decreased significantly after IV insulin from 37.9 +/- 5.4 to 35.4 +/- 3 mg/L (P =.02) and returned to basal levels thereafter. In contrast, obese, glucose-tolerant subjects had lower CBG levels than lean and obese glucose intolerant subjects (33.8 +/- 3.0 v 37.9 +/- 5.4 and 39.8 +/- 4.4 mg/L, respectively), and their serum CBG concentrations remained unchanged during FSIVGT. Mean serum-free insulin-like growth factor-I (IGF-I) concentrations steadily declined from 1.21 +/- 0.81 to 0.8 +/- 0.36 microg/L during the FSIVGT, and this effect was restricted to lean subjects. Basal serum-free IGF-I did not correlate with CBG levels at time 0, but correlated inversely with the serum CBG concentrations at 22 minutes (r = -.36, P =.04). Stepwise multivariant analysis showed that AIRg (P =.035) and S(I) (P =.046), but not free IGF-I levels, independently contributed to 28% of CBG variance at 22 minutes. These results suggest that insulin, but not IGF-I, constitutes an important negative regulator of CBG liver synthesis. Endogenous and exogenous insulin do not affect serum CBG concentrations in insulin-resistant obese subjects with preserved or decreased insulin secretion. Obese glucose-tolerant subjects are hypothesized to exhibit tonically inhibited serum CBG levels. In contrast, in lean subjects, the higher the insulin secretion the lower the serum CBG concentration. The mechanisms of this CBG inhibitory effect exerted by insulin and its implication on cortisol homeostasis and fat distribution in humans await further investigations.

Adult↗
PubMed2001

Efficacy of the long-acting octreotide formulation (octreotide-LAR) in patients with thyrotropin-secreting pituitary adenomas.

The presence of somatostatin receptors on TSH-secreting pituitary adenomas allows treatment of central hyperthyroidism with somatostatin analogs. Six women and 5 men (mean +/- SEM age, 43 +/- 3 yr) presented TSH-secreting pituitary adenomas (micro, n = 2; macro, n = 9). Seven patients had previously been treated with partial surgical removal (n = 6) and/or external radiation (n = 4) of their adenoma at least 1 yr before the study, whereas 4 patients had not been treated before somatostatin analog therapy. TSH, free T(4), and free T(3) levels were in the normal range during treatment with sc injections (n = 9) or continuous infusion (n = 2) of octreotide (280 +/- 25 microg/day). Mean thyroid hormone levels increased (P < 0.01) after the washout period (34 +/- 6 days). The patients received monthly im injections of 20 mg Octreotide-LAR. In patients with an elevated free T(4) level after 3 months (n = 1) the Octreotide-LAR dose was increased to 30 mg. After 3 months of Octreotide-LAR treatment, TSH, free T(4)/T(3), and alpha-subunit levels decreased, and 10 patients were euthyroid with normal free T(4) levels. These results remained at the same level over the next 3 months. There were no statistically significant differences in the TSH and free T(4) responses to sc octreotide or im Octreotide-LAR between previously untreated patients and patients who had undergone surgical resection and/or pituitary radiation before somatostatin analog treatment. During Octreotide-LAR treatment, minor digestive problems or moderate discomfort at the injection site, lasting less than 48 h, were reported in 6 and 5 patients, respectively. Gallbladder echographies did not reveal new gallstones during Octreotide-LAR treatment. In conclusion, this study shows that monthly im Octreotide-LAR is as effective as daily sc octreotide in controlling hyperthyroidism in patients with TSH-secreting pituitary adenomas, in both previously untreated patients and patients treated with surgery and/or pituitary radiotherapy. Octreotide-LAR is well tolerated, except for minor digestive problems or mild pain at the injection site. Therefore, Octreotide-LAR appears to be a useful therapeutic tool to facilitate medical treatment of TSH-secreting pituitary adenomas in patients who need long-term somatostatin analog therapy.

Adenoma↗
PubMed2000

Postmenopause hormone treatment in women with NIDDM or impaired glucose tolerance: the MEDIA randomized clinical trial.

OBJECTIVE: To assess the biological safety of four hormone replacement treatment (HRT) combinations in women with non insulin dependent diabetes mellitus (NIDDM) or impaired glucose tolerance (IGT). SUBJECTS AND METHODS: Randomized, double-blind, placebo-controlled trial to analyze the variation of fibrinogen, factor VII, PAI1, and TG blood levels in women (n=99), with NIDDM or IGT, receiving a 3-month course of either oral oestradiol (1 or 2 mg) combined with Chlormadinone Acetate 5 mg, or transdermal oestradiol 50 microg/24 h in association with Norethisterone Acetate (11.2 or 22.4 mg), or placebo. Follow-up lasted 3 months. RESULTS: Ninety nine patients, mean age 56 years (SD 5), mean diabetes duration 7 years (S.D. 7), mean glycated hemoglobin (7.3%) were enrolled. There was no significant difference between the groups for any of the primary hemostasis criteria (n=77). Triglycerides (TG) variation significantly differed between groups, P=0.01, from -21% in the large patch group, to +22% in the placebo group (n=82). Treatment administration routes did not significantly differ for any of the criteria. There was a significant difference in the total cholesterol variation between groups, from +8.7% in the placebo group to -10.8% in the oral 1 mg group (P=0.001). CONCLUSION: The treatments had no highly deleterious effect in these patients with NIDDM or with IGT. Long-term trials can be performed with such patients, and an hormone treatment can be prescribed to relieve symptoms. Since these patients had a well-controlled NIDDM, results might be different in less well-controlled diabetes. The data do not support the hypothesis of an impaired oestrogen effect in patients with NIDDM.

Biomarkers↗
PubMed2000

21-Hydroxylase-deficient nonclassic adrenal hyperplasia is a progressive disorder: a multicenter study.

OBJECTIVE: Our aim was to determine whether the clinical features of 21-hydroxylase-deficient nonclassic adrenal hyperplasia are correlated with either age at symptom onset or age at presentation, or both, and with the degree of adrenocortical abnormality. STUDY DESIGN: In a multicenter cohort design 220 women with nonclassic adrenal hyperplasia, with a basal or adrenocorticotropic hormone-stimulated 17-hydroxyprogesterone level >30.3 nmol/L, were studied, either prospectively (n = 39) or retrospectively (n = 181). Patients were stratified by age of presentation into 5 groups: (1) <10 years (n = 25), (2) 10 to 19 years (n = 64), (3) 20 to 29 years (n = 83), (4) 30 to 39 years (n = 30), and (5) 40 to 49 years (n = 16). Two patients >50 years old were excluded from the analysis because of age. RESULTS: Ninety-two percent of patients <10 years old had premature pubarche at presentation, whereas clitoromegaly and acne were each present in only 20% of these younger subjects. With only patients > or =10 years old considered, presenting clinical features included hirsutism (59%), oligomenorrhea (54%), acne (33%), infertility (13%), clitoromegaly (10%), alopecia (8%), primary amenorrhea (4%), and premature pubarche (4%). Among the patients >/=10 years old, the prevalence but not the degree of hirsutism increased significantly with age. Basal levels of 17-hydroxyprogesterone in adolescents were significantly higher than the levels found either in children (<10 years old) or women 40 to 49 years old (P <.01 and P <.03, respectively), although no difference was noted in the stimulated 17-hydroxyprogesterone levels between age groups. The adrenocorticotropic hormone-stimulated levels but not the basal levels of 17-hydroxyprogesterone were significantly higher in patients with clitoromegaly than in women without clitoromegaly. Alternatively, there were no differences in either basal or stimulated 17-hydroxyprogesterone levels between patients with and those without hirsutism, acne, or alopecia. CONCLUSION: In children <10 years old the most common presenting complaint was premature pubarche, whereas hirsutism and oligomenorrhea were more common in older patients. The prevalence of hirsutism increased with age, suggesting the progressive nature of nonclassic adrenal hyperplasia. Furthermore, the adrenocorticotropic hormone-stimulated levels of 17-hydroxyprogesterone were higher in patients with clitoromegaly, which suggests that the degree of adrenocortical dysfunction in nonclassic adrenal hyperplasia determines, at least in part, the clinical presentation.

17-alpha-Hydroxyprogesterone↗
PubMed2000

Association of insulin resistance with hyperandrogenia in women.

In humans, the skin is a target tissue for androgen action; hair growth and sebum secretion are under active androgen control. An increased production or metabolism of testosterone, the main active androgen, shows up clinically in dermatological symptoms such as hirsutism, hyperseborrheic acne and alopecia. Polycystic ovary syndrome (PCOS) is the most frequent androgen disorder of ovarian function. PCOS patients have amenorrhea or severe oligomenorrhea, increased testosterone levels and most often enlarged polycystic ovaries on ultrasound examination. In addition, many PCOS patients have a tendency to accumulate abdominal fat and/or to develop obesity. Some also display a particular metabolic pattern including an atherogenic lipid profile, glucose intolerance and an increased fasting insulin level, which is known to be closely linked with an insulin resistant state. Several studies have now reported that PCOS patients show increased incidence of type 2 diabetes and cardiovascular disease. In addition to being a target for androgens the skin has abundant insulin receptors on the keratinocyte surface membrane and acanthosis nigricans is a common symptom of severe insulin resistance among patients with insulin receptor disorders. However, acanthosis nigricans could also be present in PCOS women given evidence of the intensity of their insulin resistance. This presentation will review the mutual relationship between hyperandrogenia and insulin resistance, with particular attention paid to: (1) insulin secretion and insulin sensitivity in PCOS; (2) the complexity of the molecular mechanisms involved in insulin resistance; (3) the paradoxical relationship between insulin resistance and hyperandrogenia; (4) the current genetic studies; and (5) new avenues for long-term treatment of PCOS women.

Androgens↗
PubMed2000

Novel human corticosteroid-binding globulin variant with low cortisol-binding affinity.

Corticosteroid-binding globulin (CBG) is the plasma transport protein that regulates the access of glucocorticoid hormones to target cells. Genetic deficiencies of CBG are rare, and only a single human CBG variant (Trancortin Leuven) has been related so far to decreased cortisol-binding affinity. We report here on a 43-yr-old woman, referred for chronic asthenia and hypotension, with repeatedly low morning serum cortisol levels (22-61 nmol/L; normal range, 204-546 nmol/L), normal plasma ACTH levels (38-49 pg/mL; normal, <50 pg/mL), and normal urinary cortisol (10-76 nmol/24 h; normal range, 10-105 nmol/24 h). An increased percent-free (dialysable fraction) serum cortisol (8.7-9.7%, normal range, 2.9-3.9%) suggested abnormal CBG binding activity. Indeed, she had a low serum CBG concentration (24 mg/L vs. 44+/-6 mg/L in normal women), and the affinity of her CBG for cortisol was decreased (association constant, Ka = 0.12 L/nmol vs. 0.82+/-0.29 L/nmol). In her immediate family members, the serum CBG concentration and cortisol-binding activity were normal in her husband, but the four living children had slightly lower serum CBG concentrations than the reference ranges for their pre- and postpubertal status. Measurements of cortisol distribution in undiluted serum indicated that an increase in the percentage of nonprotein-bound cortisol offsets the low cortisol levels to give approximately normal concentrations of free cortisol in serum. Direct sequencing of PCR-amplified exons encoding CBG revealed that the proband was homozygous for a polymorphism (GAC-AAC) in the codon for residue 367, which results in a Asp367-->Asn substitution. Her children were heterozygous for this polymorphism. When this nucleotide change was introduced into a normal human CBG complementary DNA, for expression in Chinese hamster ovary cells, Scatchard analysis demonstrated that the Asn367 substitution reduced the affinity of human CBG for cortisol by approximately 4-fold (Ka = 0.15 L/nmol), as compared to normal recombinant CBG (Ka = 0.66 L/nmol). These results suggest that Asp367 is an important determinant of CBG steroid-binding activity and that normal negative regulation of the hypothalamic-pituitary-adrenal axis is maintained by relatively normal serum-free cortisol concentrations, despite a marked reduction in the steroid-binding affinity of this novel human CBG variant, which we have designated as CBG-Lyon.

Adrenal Cortex Diseases↗
PubMed2000

Interleukin-6 gene polymorphism and insulin sensitivity.

Type 2 diabetes and the insulin resistance syndrome have been hypothesized to constitute manifestations of an ongoing acute-phase response. We aimed to study an interleukin-6 (IL-6) gene polymorphism in relation to insulin sensitivity (IL-6 is the main cytokine involved in an acute-phase response). Subjects homozygous for the C allele at position -174 of the IL-6 gene (SfaNI genotype), associated to lower plasma IL-6 levels, showed significantly lower integrated area under the curve of serum glucose concentrations (AUCglucose) after an oral glucose tolerance test, lower blood glycosylated hemoglobin, lower fasting insulin levels, lower total and differential white blood cell count (a putative marker of peripheral IL-6 action), and an increased insulin sensitivity index than carriers of the G allele, despite similar age and body composition. A gene dosage effect was especially remarkable for AUCglucose (6.4 vs. 9.3 vs. 9.7 mmol/l in C/C, C/G, and G/G individuals, respectively). The serum concentration of fully glycosylated cortisol binding globulin (another marker of IL-6 action), suggested by concanavalin A adsorption, was lower in C/C subjects than in G/G individuals (32.6+/-2.9 vs. 37.6+/-4.6 mg/l, P = 0.03). In summary, a polymorphism of the IL-6 gene influences the relationship among insulin sensitivity, postload glucose levels, and peripheral white blood cell count.

Adult↗
PubMed2000

Sex hormone-binding globulin during puberty in normal and hyperandrogenic girls.

Human sex hormone-binding globulin (SHBG) regulates the cellular bioavailability of SHBG-bound steroid hormones. Subtle decreases in plasma SHBG levels during puberty have a perceptible effect on the androgen-estrogen balance. This SHBG decrease is more pronounced in girls with premature pubarche who are at risk to develop functional ovarian hyperandrogenism as well as insulin resistance syndrome. Insulin is a potent inhibitor of SHBG production in the liver, and there is now evidence that SHBG is a marker of hyperinsulinemia and insulin resistance that can be associated in both obese and non-obese patients with polycystic ovary syndrome. Therefore, low SHBG could be a useful tool for identifying presymptomatic individuals with diabetes mellitus type 2 including those with androgen disorders.

Female↗
PubMed1999

Xenoestrogen interaction with human sex hormone-binding globulin (hSHBG).

This study reports on some environmental chemicals with estrogenic activity (xenoestrogens) and their binding interaction for human plasma sex-hormone binding globulin (hSHBG). The binding affinity constant of these xenoestrogens was measured in equilibrium conditions by solid phase binding assay, and their ability to displace endogenous testosterone and estradiol from hSHBG binding sites was determined with an ammonium sulfate precipitation assay in native plasma from normal men and women. The data showed that some of these xenoestrogens bind hSHBG, with a reversible and competitive binding activity for both [3H]testosterone and [3H]17beta-estradiol and with no apparent decrease in the number of hSHBG binding sites. Their respective binding affinity constants were low, ranging from 0.02 to 7.8 10(5) 1 x mol(-1). However, in native plasma from normal men and women, they were able to dose-dependently increase concentrations of hSHBG-unbound testosterone and/or estradiol. In this study, 4-nonylphenol and 4-tertoctylphenol, two alkylphenols used as surfactants in many commercial products, and bisphenol A and O-hydroxybiphenyl, widely used in the plastics industry, were identified as potent hSHBG-ligands. Additionally, the flavonoid phytoestrogens genistein and naringenin were also identified as hSHBG ligands, whereas their glucoside derivatives, genistin and naringin, had no binding activity for hSHBG. From these data, it is suggested that hSHBG binding may transport some contaminant xenoestrogens into the plasma and modulate their bioavailability to cell tissues. On the other hand, xenoestrogens may also displace endogenous sex steroid hormones from hSHBG binding sites and disrupt the androgen-to-estrogen balance. Whether xenoestrogen SHBG ligands could reach high enough concentrations in the blood to expose humans to any such effect merits further investigation.

Binding, Competitive↗
PubMed1999

Plasma total and glycosylated corticosteroid-binding globulin levels are associated with insulin secretion.

In humans, steroid hormones circulate in the blood mainly bound to specific steroid transport proteins, namely corticosteroid-binding globulin (CBG) for cortisol and sex hormone-binding globulin (SHBG) for testosterone and estradiol. The binding activities of these proteins are believed to modulate the biodisposal of steroids to target cells. It has been shown in vitro that insulin is a potent inhibitor of both CBG and SHBG secretion by a human hepatoblastoma cell (HepG2) line. To further investigate this potential effect of insulin in vivo, we prospectively studied three groups of lean subjects, obese subjects, and obese subjects with glucose intolerance, all of whom were otherwise healthy. The three groups were comparable in sex and age, and in the two obese groups, body mass index, waist to hip ratio, and blood pressure were similar. Plasma total CBG concentrations (38.2 +/- 5.4 vs. 31.7 +/- 4.05 mg/L; P = 0.016) and glycosylated CBG levels (37.3 +/- 5.2 vs. 31 +/- 3.9 mg/L; P = 0.018) were significantly increased in obese subjects with glucose intolerance. Plasma CBG correlated positively with fasting glucose levels (r = 0.49; P = 0.002), hemoglobin A1c levels (r = 0.35; P = 0.03), and area under the curve of glucose after an oral glucose tolerance test (r = 0.45; P = 0.005) and correlated negatively with the insulin response to i.v. glucose (AIRg; -0.38, P = 0.02) as well as to oral glucose (r = -0.40; P = 0.01) challenge tests. CBG levels did not covariate with insulin sensitivity. Multiple linear regression analysis showed that only AIRg contributed to the variability of the CBG concentration (P = 0.03), explaining 41% of its variance. Morning cortisol levels did not differ between the groups and did not correlate to any of the glucose or insulin metabolism parameters. Because carbohydrate chains influence the biological activity and half-life of glycoproteins, we analyzed the migration profile of CBG by Western blot and the interaction of CBG with lectin, Con A. The results indicated that the CBG mol wt and interaction with Con A did not differ between lean and obese patients. These data favor the hypothesis that the inhibitory effect of insulin on CBG liver secretion might be relevant in vivo and therefore contribute to decrease CBG levels in obese patients with enhanced insulin secretion. In both men and women, SHBG levels correlated negatively with fasting glucose (r = -0.55; P < 0.0001) and hemoglobin A1c (r = -0.38; P = 0.02) and positively with insulin sensitivity (S(I); r = 0.65; P = 0.003 and r = 0.63; P = 0.007 in men and women, respectively), but not with insulin secretion. The disposition index (S(I) x AIRg) was significantly decreased in the obese, glucose-intolerant subjects, suggesting that AIRg was inadequate for their degree of insulin resistance. The disposition index correlated positively with plasma SHBG levels (r = 0.52; P = 0.001) and negatively with plasma CBG levels (r = -0.54; P = 0.001). Our data suggest that CBG is a marker of insulin secretion in a similar way as SHBG is a marker of insulin sensitivity. As high plasma CBG levels have been associated with increased incidence of type 2 diabetes, this important issue merits further investigations.

Adult↗