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W Ricart-Engel

Publications and source records attributed to W Ricart-Engel.

8 recordsLinked to original sources
PubMed1999

[Insulin secretion in women and insulin sensitivity in men constitute independent determinants of serum leptin concentration].

BACKGROUND: Although its effects in man are still unknown, leptin may play a role in the regulation of insulin sensitivity and insulin secretion. The aim of this study was to determine if these parameters are independent predictors of serum leptin levels. SUBJECTS AND METHODS: Twenty men and 22 women were evaluated through several anthropometric parameters, including percent fat mass (PFM), which was calculated using bioelectric impedance. A standard oral glucose tolerance test (OGTT) was performed in all subjects. Insulin sensitivity (SI) and insulin-secretion (AIRg) were determined through minimal model analysis. RESULTS: Area under the curve for glucose (AUCglu) and insulin (AUCins) levels after OGTT correlated with serum leptin level in men (r = 0.58, p = 0.005 and r = 0.72, p < 0.0001, respectively). Only AUCins was associated with serum leptin levels in women (r = 0.50, p = 0.01), but this correlation disappeared after controlling for PFM. A linear correlation between serum leptin level and SI was observed (r = -0.67, p = 0.001, in men; r = -0.82, p < 0.0001, in women). In a multiple regression analysis, PFM (p = 0.0005), waist-to-hip ratio (p = 0.007) and SI (p = 0.007) independently predicted serum leptin level in men (R2 = 0.82). In women with normal OGTT, only PFM (p = 0.0005) and insulin-secretion (p = 0.02) predicted serum leptin level (R2 = 0.85). CONCLUSIONS: Insulin-sensitivity in men, and insulin-secretion (calculated after intravenous glucose) in women independently predict serum leptin level. Furthermore, insulin response after oral glucose is independently associated with serum leptin level only in men. Leptin is a marker of insulin resistance in man, and, in this sense, might confer cardiovascular risk.

Adult↗
PubMed1998

Leptin is involved in gender-related differences in insulin sensitivity.

BACKGROUND: Although the effects of insulin on leptin levels are relatively well characterized, the possible actions of leptin on insulin sensitivity are not so well studied. This study was undertaken to examine whether gender-related differences in insulin sensitivity could be explained partially by leptin levels. SUBJECTS: The study involved 22 women (13 obese) and 20 (11 obese) fat mass- and age-matched men. All participants were healthy. MEASUREMENTS: Several anthropometric measures of body fatness were quantified and the percentage of body fat was determined through bioelectric impedance. Oral glucose tolerance test and a frequently sampled intravenous glucose tolerance test was performed in all subjects. Serum leptin was measured by radioimmunoassay. RESULTS: Nine lean women (BMI 20.4 +/- 2 kg m2 mean +/- SD) showed increased leptin levels (7.8 +/- 2.7 vs. 4.3 +/- 1.3 micrograms/l, P = 0.003), increased insulin sensitivity (5.2 +/- 1.3 vs. 2.9 +/- 0.9 min-1/mU/l, P = 0.001) and similar fat mass (11.1 +/- 3.7 vs. 13.2 +/- 7.8 kg, P = NS) in comparison with 9 age-matched lean men (33.6 +/- 6 vs. 34.5 +/- 6.3 years, P = NS). Thirteen obese women (BMI 32.5 +/- 2.7) kg m2 also showed increased leptin levels (29.6 +/- 8.4 vs. 11.7 +/- 4.8 micrograms/l, P < 0.0001), increased insulin sensitivity (1.7 +/- 0.7 vs. 0.95 +/- 0.9 min-1 mU/l, P = 0.04) and similar fat mass (34.4 +/- 8.0 vs. 30.9 +/- 9.6 kg, P = NS) in comparison with 11 age-matched obese men (34.5 +/- 7.8 vs. 38.7 +/- 8.2 years, P = NS). A strong linear association between leptin levels and insulin sensitivity (Si) was found (r = -0.67, P = 0.001, in men; r = -0.82, P < 0.0001, in women). After controlling for percentage of body fat, this association remained significant only in men (r = -0.56, P = 0.01, in men; r = -0.30, P = NS in women). In stepwise regression analysis models, both gender (P = 0.00001) and leptin (P = 0.00001) contributed to 67% of the variance in Si independently of body fat. CONCLUSIONS: Leptin levels and gender contribute to the variance of insulin sensitivity, independently of body fat. These results suggest that leptin could affect insulin sensitivity.

Adult↗
PubMed1998

Serum ferritin as a component of the insulin resistance syndrome.

OBJECTIVE: In epidemiological studies, serum ferritin was the second-strongest determinant of blood glucose (after BMI) in regression models and the third-strongest determinant of serum insulin (after BMI and age). Its concentration also correlated positively with plasma triglycerides and apolipoprotein B concentrations, and negatively with HDL2 cholesterol. We hypothesized that serum ferritin could be a marker of insulin resistance. RESEARCH DESIGN AND METHODS: Oral glucose tolerance and insulin sensitivity (SI, minimal model method) were prospectively evaluated in 36 healthy subjects. The relationship between serum ferritin and metabolic control (as measured by HbA1c levels) was also studied in 76 consecutive NIDDM patients. RESULTS: In healthy subjects, log-transformed serum ferritin (LOGFER) correlated with basal serum glucose (r = 0.44, P = 0.007), but not with BMI, age, systolic or diastolic blood pressure, total cholesterol, VLDL cholesterol, HDL cholesterol, total triglycerides, VLDL triglycerides, serum insulin, or HbA1c (all P = NS). Identical results were obtained when the two lowest quartiles of serum ferritin were evaluated separately. However, in the two highest quartiles, LOGFER correlated with BMI (0.50, P = 0.02), diastolic blood pressure (r = 0.8, P < 0.0001), serum LDL cholesterol (r = 0.57, P = 0.01), VLDL cholesterol (r = 0.48, P = 0.03), total cholesterol and HDL2 and HDL3 subtractions of HDL cholesterol (r = -0.68, -0.76, -0.55, P = 0.001. < 0.0001, and 0.01, respectively), total triglycerides (r = 0.60, P = 0.006), HDL2/HDL3 quotient (P = -0.71, P = 0.001), VLDL triglycerides (r = 0.65, P = 0.004), and serum uric acid (r = 0.51, P = 0.03), but not with systolic blood pressure (r = 0.38, P = 0.15). After adjusting for BMI, only the correlations between LOGFER and diastolic blood pressure (r = 0.7, P = 0.002) and HDL2/HDL3 quotient (r = -0.63, P = 0.01) remained significant. Strong correlations between LOGFER and glucose area under the curve during oral glucose tolerance test (Pearson's r = 0.73, P = 0.001) and SI (r = -0.68, P = 0.001), which remained significant after controlling for BMI, were observed. LOGFER (beta = -0.44, P = 0.01) and BMI (beta = -0.52, P = 0.004) constituted independent predictors of insulin sensitivity in a multivariate analysis (R2 = 0.68). In 76 consecutive NIDDM outpatients, serum glucose (P < 0.00001) and LOGFER (P = 0.03) independently predicted the value of HbA1c (R2 = 0.40) in a multiple linear regression analysis. CONCLUSIONS: The correlations among serum ferritin and diastolic blood pressure, HDL quotient, glucose area under the curve, and SI suggest that serum ferritin could be a marker of the insulin resistance syndrome. Serum ferritin may also be an independent determinant of poor metabolic control in the diabetic patient.

Adult↗
PubMed1996

The relation between thyroid function and nutritional status in HIV-infected patients.

OBJECTIVE: The effects of human immunodeficiency virus (HIV) infection on thyroid function have been reported in only a few studies with discrepant results. The aim of this study was to assess the relation between nutritional status and thyroid function in HIV infected patients. DESIGN: Prospective, cross-sectional study. SETTING: A 500-bed teaching and referral hospital serving a population of 450,000. PATIENTS: Seventy-five consecutive HIV infected patients between 21 and 40 years of age (mean 31.8 +/- 0.9 years). MEASUREMENTS: Nutritional status was evaluated using the body mass index (BMI), triceps skinfold thickness (TSF), mid-arm muscle circumference (MAMC), and serum albumin concentration (SA). Hormone assays for serum T4, free thyroxine index (FTI), T3, reverse triiodothyronine (rT3), thyroxine-binding globulin (TBG), TSH and simultaneous CD4 lymphocyte counts were determined in all patients. RESULTS: Clinical stage was significantly related to nutritional status (P = 0.0001 for BMI, P = 0.0002 MAMC). The more poorly nourished groups had low mean serum T3 and rT3 levels, particularly for muscular (P = 0.0001 for T3 and P = 0.0076 for rT3) and visceral (P = 0.00001 for T3 and P = 0.0021 for rT3) protein compartments. Multivariate analysis showed that two factors, SA and MAMC, correlated significantly and independently with serum T3 and rT3. CONCLUSIONS: A close relation exists between serum thyroid hormone levels and nutritional status in HIV infected patients. These patients are probably euthyroid and the abnormal findings in the thyroid function tests are thus a reflection of the severity of illness.

Adult↗
PubMed1994

Pre-clinical Cushing's syndrome: report of three cases and literature review.

Pre-Cushing's syndrome (PCS) is defined as an overproduction of cortisol by an adrenal adenoma, without physical changes on clinical examination. Three patients with PCS were recently diagnosed among 21 consecutive patients suffering from adrenal 'incidentaloma'. All patients showed nonsuppression of serum and urinary cortisol following 2 and 8 mg of dexamethasone (DXM), and suppressed or normal baseline plasma ACTH. Unilateral uptake of radiolabelled iodocholesterol, which persisted after DXM, was uniformly present. The authors review 36 patients with PCS previously reported. This entity probably constitutes a transition from classic 'nonfunctional' adrenal adenoma to cortisol-producing adenoma. Uniform guidelines in the management of PCS cannot yet be given, but surgical intervention is usually required to prevent the development of long-term complications of subtle corticoid excess.

Adenoma↗