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Biomedical subjects

B L Wajchenberg

Publications and source records attributed to B L Wajchenberg.

At least 19 recordsLinked to original sources

Previous exercise attenuates muscle sympathetic activity and increases blood flow during acute euglycemic hyperinsulinemia.

Insulin infusion causes muscle vasodilation, despite the increase in sympathetic nerve activity. In contrast, a single bout of exercise decreases sympathetic activity and increases muscle blood flow during the postexercise period. We tested the hypothesis that muscle sympathetic activity would be lower and muscle vasodilation would be higher during hyperinsulinemia performed after a single bout of dynamic exercise. Twenty-one healthy young men randomly underwent two hyperinsulinemic euglycemic clamps performed after 45 min of seated rest (control) or bicycle exercise (50% of peak oxygen uptake). Muscle sympathetic nerve activity (MSNA, microneurography), forearm blood flow (FBF, plethysmography), blood pressure (BP, oscillometric method), and heart rate (HR, ECG) were measured at baseline (90 min after exercise or seated rest) and during hyperinsulinemic euglycemic clamps. Baseline glucose and insulin concentrations were similar in the exercise and control sessions. Insulin sensitivity was unchanged by previous exercise. During the clamp, insulin levels increased similarly in both sessions. As expected, insulin infusion increased MSNA, FBF, BP, and HR in both sessions (23 +/- 1 vs. 36 +/- 2 bursts/min, 1.8 +/- 0.1 vs. 2.2 +/- 0.2 ml.min(-1).100 ml(-1), 89 +/- 2 vs. 92 +/- 2 mmHg, and 58 +/- 1 vs. 62 +/- 1 beats/min, respectively, P < 0.05). BP and HR were similar between sessions. However, MSNA was significantly lower (27 +/- 2 vs. 31 +/- 2 bursts/min), and FBF was significantly higher (2.2 +/- 0.2 vs. 1.8 +/- 0.1 ml.min(-1).100 ml(-1), P < 0.05) in the exercise session compared with the control session. In conclusion, in healthy men, a prolonged bout of dynamic exercise decreases MSNA and increases FBF. These effects persist during acute hyperinsulinemia performed after exercise.

Acute Disease↗

Effect of thalidomide and rosiglitazone on the prevention of diabetic retinopathy in streptozotocin-induced diabetic rats.

AIMS/HYPOTHESIS: Our aim was to compare the therapeutic effect of thalidomide and rosiglitazone on the prevention of diabetic retinopathy in streptozotocin-induced diabetic rats. METHODS: Male Holtzman rats of 6 to 8 weeks of age and weighing 170+/-30 g were randomly divided into four groups: control ( n=13), untreated diabetic ( n=17) and diabetic rats treated with thalidomide (200 mg kg(-1) day(-1)) ( n=8) or rosiglitazone (1 mg kg(-1) day(-1)) ( n=22) for 3 months. Diabetes was induced by streptozotocin with the rats having a body weight of 70 mg/kg. After treatment, vascular endothelial growth factor (VEGF) concentrations in ocular fluid were compared between the different groups, and retinal capillary basement membrane thickness was measured by electron microscopy. RESULTS: Higher VEGF concentrations in ocular fluid and thicker basement membranes were observed in untreated diabetic rats compared to the control rats. Similar VEGF concentrations and basement membrane thickness were observed for the thalidomide-treated group compared with the control group, whereas no difference in these parameters was observed between the rosiglitazone-treated rats and the control or untreated diabetic rats. CONCLUSIONS/INTERPRETATION: Our findings confirm the association between VEGF concentrations and diabetic retinopathy as suggested by other investigators. Thalidomide, but not rosiglitazone, was associated with the inhibition of basement membrane thickening and the blockade of the increase of VEGF in ocular fluid, thus representing a potential therapeutic drug for the prevention of diabetic retinopathy.

Angiogenesis Inhibitors↗

Adrenocortical carcinoma: clinical and laboratory observations.

BACKGROUND: The clinical features and natural history of adrenocortical carcinoma are highly dependent on the type of center reporting their experience. Observations from oncology services suggest a high incidence of nonfunctioning tumors, whereas reports from endocrine clinics emphasize excessive corticoid and androgen production in the majority of tumors. The incidence rate and natural history of childhood adrenal carcinoma generally has been under emphasized. METHODS: Over the past 17 years, the authors have evaluated and treated 47 patients with adrenocortical carcinoma referred to the University of Sao Paulo, 22 of whom were children. RESULTS: There is a bimodal age incidence of adrenal carcinoma, with the disease peaking in the first and fourth decades of life. Childhood adrenal carcinoma is characterized by a high rate of incidence of virilization, marked overproduction of androgens, and a less aggressive clinical course, and appears to be more amenable to surgical and other therapeutic modalities. By contrast, adrenocortical carcinoma occurring in adults presents more commonly as a mixed Cushing and virilizing syndrome, with overproduction of corticoids and androgens and a far more aggressive clinical course, leading to rapid death within months or years. Nonfunctioning adrenocortical carcinoma is less common; it generally occurs in older adults and exhibits a rapid downhill course. Modern day imaging methods have improved the diagnosis and staging of adrenal carcinoma greatly. In the authors' experience, the histologic criteria of Weiss appeared to predict tumor prognosis most accurately, whereas immunologic markers, cytoskeletal markers, DNA ploidy, cell phase markers, and oncogenic probes have yielded inconsistent results to date. Surgical removal of a localized tumor remains the best hope for long term survival. Medical therapy with mitotane and its successors in patients with Stage III or IV (MacFarlane system as modified by Sullivan et al.) disease appear to have added little to longevity or quality of life. CONCLUSIONS: When diagnosed in children, adrenal carcinoma is associated with virilism and a less aggressive natural history; however, when it occurs in adults, the disease presents more commonly as a mixed Cushing-virilizing syndrome and has a virulent course. The Weiss histologic criteria appear to correlate best with disease prognosis, but other histochemical, cell cycle, and genetic markers have not, to date, aided in disease management.

Adrenal Cortex Neoplasms↗

Subcutaneous and visceral adipose tissue: their relation to the metabolic syndrome.

Methods for assessment, e.g., anthropometric indicators and imaging techniques, of several phenotypes of human obesity, with special reference to abdominal fat content, have been evaluated. The correlation of fat distribution with age, gender, total body fat, energy balance, adipose tissue lipoprotein lipase and lipolytic activity, adipose tissue receptors, and genetic characteristics are discussed. Several secreted or expressed factors in the adipocyte are evaluated in the context of fat tissue localization. The body fat distribution and the metabolic profile in nonobese and obese individuals is discussed relative to lipolysis, antilypolysis and lipogenesis, insulin sensitivity, and glucose, lipid, and protein metabolism. Finally, the endocrine regulation of abdominal visceral fat in comparison with the adipose tissue localized in other areas is presented.

Abdomen↗

Familial growth hormone deficiency with mutated GHRH receptor gene: clinical and hormonal findings in homozygous and heterozygous individuals from Itabaianinha.

OBJECTIVE: To characterize clinically and hormonally the syndrome of autosomal recessive familial growth hormone deficiency (FGHD) recently identified in Itabaianinha, Sergipe, Brazil, caused by a novel mutation (mt) that inactivates the growth hormone-releasing hormone receptor (GHRH-R) gene. DESIGN: Clinical and hormonal evaluations were performed in 21 FGHD individuals (mt/mt group) aged 8 to 63 years, 13 heterozygotes for the GHRH-R mutation (wt/mt group) and 5 homozygotes for the wild type (wt) allele (wt/wt group), identified by genotyping of peripheral blood leukocyte DNA. METHODS: Clinical and hormonal characterization included physical examination and measurement of GH, IGF-I, IGF binding protein-3 (IGFBP-3), cortisol, prolactin, LH, FSH, and free thyroxine (FT4). RESULTS: Clinical features were consistent with isolated growth hormone deficiency. Height was significantly reduced in the mt/mt group compared with the wt/mt group (mean height standard deviation score (SDS) +/- s.d.: -7.35+/-1.37 vs -1.84+/-1.44 respectively, P<0. 0001), and the wt/wt group (-1.85 +/- 0.81, P=0.0007). The height of the 13 wt/mt subjects did not differ from the 5wt/wt individuals. Serum GH, IGF-I, IGF-I SDS, IGFBP-3 and IGFBP-3 SDS were all significantly lower in the mt/mt group than in the wt/mt and wt/wt groups. Two affected children treated with GH for 1 year showed a normal growth response. Serum IGF-I and IGF-I SDS were lower in wt/mt compared with wt/wt group, but did not reach statistical significance. IGF-I and IGF-I SDS correlated inversely with age in wt/mt group. CONCLUSIONS: FGHD due to an autosomal recessive GHRH-R gene mutation leads to marked dwarfism, phenotypically and hormonally indistinguishable from other forms of isolated GH deficiency. Heterozygotes for the GHRH-R mutation appear to have a partial defect in the GH/IGF axis, with no apparent height impairment.

Adolescent↗

Analysis of gonadotropin pulsatility in hirsute women with normal menstrual cycles and in women with polycystic ovary syndrome.

OBJECTIVE: To study the relation between plasma gonadotropin pulsatility, androgen levels, and estrogen levels in patients with polycystic ovary syndrome (PCOS), in hirsute women with normal menstrual cycles, and in healthy women. DESIGN: Prospective study. SETTING: University medical center-based cellular and molecular endocrinology laboratory. PATIENT(S): Eight healthy women (group 1), 9 hirsute women with normal menstrual cycles (group 2), and 19 women with PCOS (group 3). INTERVENTION(S): Plasma concentrations of LH and FSH were measured by RIA every 15 minutes for 12 hours. MAIN OUTCOME MEASURE(S): Rhythmic parameters of 12-hour LH and FSH secretion. RESULT(S): Rhythmic parameters of 12-hour LH secretion were significantly higher in patients with PCOS (group 3) than in controls (group 1) or in hirsute women with normal menstrual cycles (group 2). The frequency of LH pulses was statistically higher in patients with PCOS (group 3) than in controls (group 1). Statistically significant correlations were found when the frequency of LH pulses was plotted against basal LH concentrations and rhythmic parameters of 12-hour LH secretion. CONCLUSION(S): Luteinizing hormone pulse amplitude was higher in patients with PCOS than in hirsute women with normal menstrual cycles or in healthy women. The LH pulse frequency was increased only in patients with PCOS compared with healthy women and not in hirsute women with normal menstrual cycles.

Adolescent↗

Frequent loss of heterozygosity at chromosome 3p14.2-3p21 in human pancreatic islet cell tumours.

OBJECTIVE: Pancreatic islet betacell tumours occur either sporadically or as part of inherited neoplastic syndromes, most commonly multiple endocrine neoplasia (MEN) type 1. Recently, a transgenic mouse model has been established in which the expression of the SV40 large T antigen was targeted to betacells by the rat insulin promoter, leading to the development of multiple pancreatic betacell tumours. In the advanced stages of tumour evolution, these tumours exhibited a high prevalence of loss of heterozygosity (LOH) on mouse chromosomes 9 and 16, at regions syntenic with regions 3q, 3p21, 6q12, 15q24 and 22q of the human genome. DESIGN: Loss of heterozygosity in human islet cell tumours was analysed in a PCR based approach at regions of the human genome syntenic with the mouse loci linked to pancreatic betacell tumours as well as the MEN1 gene on chromosome 11q13. These included 35 microsatellite markers in the human chromosomal regions 3q, 3p21, 6q12, 11q13, 15q24 and 22q. PATIENTS: 21 patients diagnosed with insulinoma were analysed. Histologically, 16 tumours were benign, while 5 were malignant insulinomas. RESULTS: Thirteen of 21 (62%) tumours were found to have loss of genetic material on chromosome 3. The shortest region of overlap implicated a deletion at 3p14.2-3p21 region, corresponding to the marker D3S1295. We did not detect a substantial frequency of LOH in the other syntenic regions, except for the region of MEN 1 gene on 11q13 found to be deleted in 6 (29%) cases, including 3 of 4 tumours from MEN 1 families. Deletions of 3p14. 2-3p21 were observed in 8 of 15 (53%) benign tumours, and in 5 of 6 (83%) malignant neoplasms. CONCLUSIONS: These results indicate the high frequency of 3p14.2-3p21 deletions in human pancreatic betacell neoplasms. These finding suggest the presence of a tumour suppressor gene in this region, that may be important in the microevolution of these tumours towards malignancy.

Adult↗

Postexercise responses of muscle sympathetic nerve activity and blood flow to hyperinsulinemia in humans.

Although insulin and exercise cause dramatic changes in physiological parameters, the impact of exercise on neural and hemodynamic responses to insulin administration has not been described. In a study of the effects of a single bout of exercise on blood pressure (BP), muscle sympathetic nerve activity (MSNA), and forearm blood flow (FBF) responses to insulin infusion during the postexercise period, 11 healthy men underwent, in a random order, two hyperinsulinemic euglycemic clamps performed after 45 min of 1) bicycle exercise (50% peak O(2) uptake, Exercise session) and 2) seated rest (Control session). Data were analyzed during baseline and steady-state periods. Although insulin levels and insulin sensitivity were similar, baseline plasma glucose levels were significantly lower in the Exercise than in the Control session. Mean BP was significantly lower (3%) and FBF was higher (27%) in the Exercise session. Exercise increased insulin-induced MSNA enhancement (84%) without changing FBF and BP responses to hyperinsulinemia. In conclusion, a single bout of exercise that does not alter insulin sensitivity exacerbates insulin-induced increase in MSNA without changing FBF and BP responses to hyperinsulinemia.

Adult↗

Overnight lowering of free fatty acids with Acipimox improves insulin resistance and glucose tolerance in obese diabetic and nondiabetic subjects.

Obesity is commonly associated with elevated plasma free fatty acid (FFA) levels, as well as with insulin resistance and hyperinsulinemia, two important cardiovascular risk factors. What causes insulin resistance and hyperinsulinemia in obesity remains uncertain. Here, we have tested the hypothesis that FFAs are the link between obesity and insulin resistance/hyperinsulinemia and that, therefore, lowering of chronically elevated plasma FFA levels would improve insulin resistance/hyperinsulinemia and glucose tolerance in obese nondiabetic and diabetic subjects. Acipimox (250 mg), a long-acting antilipolytic drug, or placebo was given overnight (at 7:00 P.M., 1:00 A.M., 7:00 A.M.) to 9 lean control subjects, 13 obese nondiabetic subjects, 10 obese subjects with impaired glucose tolerance, and 11 patients with type 2 diabetes. Euglycemic-hyperinsulinemic clamps and oral glucose tolerance tests (75 g) were performed on separate mornings after overnight Acipimox or placebo treatment. In the three obese study groups, Acipimox lowered fasting levels of plasma FFAs (by 60-70%) and plasma insulin (by approximately 50%). Insulin-stimulated glucose uptake during euglycemic-hyperinsulinemic clamping was more than twofold higher after Acipimox than after placebo. Areas under the glucose and insulin curves during oral glucose tolerance testing were both approximately 30% lower after Acipimox administration than after placebo. We conclude that lowering of elevated plasma FFA levels can reduce insulin resistance/hyperinsulinemia and improve oral glucose tolerance in lean and obese nondiabetic subjects and in obese patients with type 2 diabetes.

Adult↗

A study of patients with Nelson's syndrome.

OBJECTIVE: The prevalence of Nelson's syndrome has varied greatly, at least in part because of the variability of the diagnostic criteria employed by different authors. We define Nelson's syndrome as the presence of an enlarging pituitary tumour associated with elevated fasting plasma ACTH levels and hyperpigmentation in patients with Cushing's disease after bilateral adrenalectomy. We have compared patients with Cushing's disease who developed Nelson's syndrome after bilateral adrenalectomy with those who did not. Our objective was to find differences between the two groups which might predict the development of Nelson's syndrome. PATIENTS AND METHODS: We have reviewed the records of 30 patients with Cushing's disease after adrenalectomy, and divided them into two groups; I: 14 who developed Nelson's syndrome and II, 16 who did not. The two groups of patients were compared in their clinical, laboratory and imaging data as well as in the therapeutic procedures that preceded the adrenalectomy. RESULTS: The comparison between the two groups of patients demonstrated a highly significant difference in relation to the development of cutaneous hyperpigmentation (100% in group I and 19% in group II) and neuro-ophthalmological symptoms (21% in group I and 0% in group II) after adrenalectomy. There were no significant differences in laboratory data before adrenalectomy. After adrenalectomy, plasma ACTH levels increased significantly in the patients of both groups, but to much higher levels in those who developed Nelson's syndrome. Plasma ACTH concentrations above 154 pmol/l occurred only in the subjects with Nelson's syndrome. Before adrenalectomy, a pituitary tumour was more frequent in the patients who developed Nelson's syndrome (55% vs. 33% at transsphenoidal pituitary exploration). Pituitary surgery and irradiation were undertaken before adrenalectomy in approximately equal numbers of patients in each group. DISCUSSION: The prevalence of Nelson's syndrome was 47% in our series of 30 patients with Cushing's disease after bilateral adrenalectomy. No clinical or laboratory data before adrenalectomy predicted the development of the syndrome. The value of prophylactic pituitary irradiation could not be evaluated from our clinical material. However, after adrenalectomy, the presence of hyperpigmentation and ACTH levels above 154 pmol/l had positive predictive value for the development of Nelson's syndrome. In this situation magnetic resonance imaging (MRI) of the pituitary is mandatory and, if no tumour is detected, MRI should be repeated at intervals.

Adolescent↗

Mechanism of the diabetogenic action of cyclosporin A.

To investigate the mechanism of diabetogenic action of cyclosporin A (CsA), 7 male Wistar albino rats received 10 mg/kg/day of the drug for 4 weeks (CsA). The results were compared with controls (C); blood CsA levels measured weekly remained stable throughout the experiment (mean +/- SEM) (X = 2657.9+/-155.1 ng/ml). Intravenous glucose load (0.75 g/kg) performed after 2 weeks of CsA therapy showed glucose intolerance in treated animals as evaluated by the glucose area under the curve (CsA = 409.2+/-17.8 vs. C = 313.3+/-12.6 umol x ml(-1) x min(-1)) (p < 0.05) with insulin levels being similar in the two groups (CsA = 8603.9+/-1645.5 vs. C = 9571.9+/-828.5 pmol x ml(-1) x min(-1)). After 4 weeks of CsA administration, glucose intolerance was maintained (CsA = 398.6+/-35.6 vs. C = 301.7+/-23.0 umol x ml(-1) x min(-1)) (p < 0.05) associated with a significant decrease in insulin secretion (CsA = 4404.9+/-2392.0 vs. C = 10075.9+/-2861.0 pmol x ml(-1) x min(-1) (p < 0.05). These results suggest that CsA induced a state of insulin resistance preceding the failure of insulin secretion. After 4 weeks, the pancreatic insulin content was also decreased (CsA = 0.7+/-0.1 vs. C = 1.4+/-0.5 mU/mg) (p < 0.05). Maximal insulin binding to isolated adipocytes was not affected by CsA (CsA = 7.4+/-2.6 vs. C = 6.4+/-2.0%), although glucose transport and oxidation decreased after CsA treatment (p < 0.05). In conclusion, glucose intolerance induced by CsA in Wistar albino rats is due to decreased insulin production and impaired insulin action by a post-binding mechanism.

Adipocytes↗

Effect of fat distribution on the pharmacokinetics of cortisol in obesity.

OBJECTIVE: Patients with predominantly upper body obesity are at greater risk for developing diabetes mellitus, hyperlipidemia, hypertension, and cardiovascular disease. Little is known about the mechanisms involved in the regulation of regional body distribution. It has been accepted that the accumulation of fat into adipose tissue depends on regional metabolic regulation of adipocytes and that glucocorticoids play a role in this mechanism. The aim of the present study is to investigate how the pharmacokinetics of cortisol correlate to intraabdominal and subcutaneous fat distribution in obese patients. METHODS: A group of 24 obese patients (13 males and 11 females) were submitted to a CT scan for intraabdominal and subcutaneous fat area evaluation. A 30-min cortisol infusion (0.25 mg/kg) was administered and plasma cortisol was measured over 6 hours. RESULTS: Patients with larger intraabdominal fat areas were found to have a higher cortisol clearance than those with lower intraabdominal fat areas. Cortisol clearance (both, absolute and body-weight corrected) showed a statistically significant correlation with intraabdominal fat area, either expressed by waist-hip ratio or obtained by computerized tomography. CONCLUSIONS: These findings indicate a more effective clearance capability for cortisol in patients with central obesity resulting in lowered cortisol plasma levels despite an increased cortisol secretion observed in this patient group.

Abdomen↗

A virilizing Leydig cell tumor of the ovary associated with stromal hyperplasia under gonadotropin control.

A 34-yr-old nulliparous black woman presented with hair loss, facial hirsutism, irregular menses and infertility associated with greatly increased serum total testosterone levels. The adrenal glands and the ovaries were normal on radiological and ultrasonographic investigation. Catheterization of the veins draining from the adrenal glands and the ovaries yielded testosterone levels of 20.3 nmol/L and 20.0 nmol/L in the right and the left adrenal veins, respectively, and 17.9 nmol/L and 27.4 nmol/L in the right and left ovaries venous plexus, respectively. Sequencial dexamethasone and ethynyl estradiol suppression test showed a decrease in cortisol level with no change in total testosterone level on dexamethasone while an increase in testosterone from 10.5 nmol/L to 20.1 nmol/L was observed ten days after ethynil estradiol had been associated to dexamethasone. When a gonadotropin-releasing hormone agonist (gonadorelin 3.5 mg i.m.) was administered for 2 months, serum gonadotropins levels decreased to less than 2 IU/L, total testosterone to 3.8 nmol/L and estradiol to less than 36 pmol/L. The patient was submitted to a pelvic exploratory laparotomy and a left salpingo-oophorectomy was performed. A solid and circumscribed ovarian tumor of 1.0 cm in diameter was found. The pathological diagnosis was a Leydig cell tumor with surrounding stromal hyperplasia. These findings may suggest that this tumor was gonadotropin-dependent being indirectly stimulated by ethynil estradiol, through a sensitization of the pituitary gonadotropes and increase in gonadotropin levels and suppressed by a gonadotropin-releasing hormone agonist.

Adult↗

Insulin resistance in limb and trunk partial lipodystrophy (type 2 Köbberling-Dunnigan syndrome).

We studied insulin action in two patients with limb and trunk partial lipodystrophy with hirsutism and acanthosis nigricans. Glucose was normal in one of the patients and slightly above normal in the other during an oral glucose tolerance test (OGTT). An intravenous glucose tolerance test (IVGTT) was normal in both patients. Basal and glucose-stimulated insulin levels were elevated in both the OGTT and IVGTT in both patients. The response of plasma glucose to exogenously administered insulin was decreased. A euglycemic-hyperinsulinemic clamp performed in patient no. 2 indicated insulin resistance, which was not corrected by reducing the increased basal level of serum free fatty acids (FFAs). Binding of insulin to neck adipocytes was normal in both subjects, but glucose transport and oxidation in these cells was impaired. Insulin binding to abdominal adipocytes was increased in one patient whose adipocytes displayed higher glucose transport at low insulin concentrations. Glucose oxidation was decreased in abdominal adipocytes of both patients. We conclude that insulin resistance in Köbberling-Dunnigan type 2 partial lipodystrophy is not related to an alteration of the insulin molecule or to changes in insulin binding, but is more likely associated with a postreceptor defect, since glucose oxidation was impaired in adipocytes of the neck and abdomen.

Adult↗

Human insulin allergy-immediate and late type III reactions in a long-standing IDDM patient.

UNLABELLED: Human insulin allergy-immediate or late type III reaction-is a rare event. We report the case of a 33-year-old female patient with insulin-dependent diabetes mellitus for 25 years who presented, in the last 8 years, mild but generalized urticaria partially controlled with oral antihistamines. There was no improvement after changing from mixed beef-pork to human insulin. In the last 3 years another allergic manifestation began: small, localized, subdermal and painful non-erythematous nodules with central hematomas at injection sites, occurring 6-8 h after the insulin injection and lasting for 48 h. The following maneuvers had no benefit: (1) Human insulin (NPH or Lente) administered with dexametasone or xylocain locally, (2) Short acting human insulin with or without previous boiling, (3) Anti-histamine cetirizine dihydrochloride-10 mg/day. The allergic symptoms disappeared only after treatment with short acting human insulin (up to 100 U/day) associated to prednisone-40 mg/day and cetirizine dihydrochloride for 4 months. However, after stopping prednisone the urticaria reappeared and it was relieved with insulin desensitization. The pain at the site of injections persisted. CONCLUSION: This long-standing IDDM patient presented two types of reactions to human insulin: the immediate type (systemic urticaria), treated with antihistamines and desensitization, and the Arthus' type III reaction (nodules and hematomas occurring 6-8 h after the insulin injection) that required glucocorticoid therapy for more than 4 months.

Adult↗

Resistance to vasopressin action on the kidney in patients with Cushing's disease.

OBJECTIVE: To assess the plasma levels and action of arginine vasopressin (AVP) in patients with Cushing's disease. There are many reports that patients with Addison's disease have increased AVP levels associated with hyponatraemia and hypoosmolality, but none on the dynamics of secretion of this neurohormone during osmolality-based stimulation in patients with chronic hypercortisolism. DESIGN AND SUBJECTS: The plasma AVP concentration and the urinary and plasma osmolality after a 7.5-h water deprivation test (WDT) were evaluated in 13 patients with Cushing's disease and 15 normal (control) individuals. In patients with Cushing's disease we also assessed the urinary osmolality in response to 10 micrograms i.v. desmopressin (DDAVP) administered at the end of the WDT. RESULTS: At the end of the WDT, urinary osmolality was significantly lower in patients with Cushing's disease (511.5 +/- 148.5 mOsm/l) than in the normal subjects (981.1 +/- 107.1 mOsm/l, P < 0.001), whereas plasma osmolality did not differ between the two groups. Consequently, the urine/plasma osmolality ratio (Uosm/Posm) was lower in patients with Cushing's disease than in normal individuals (1.8 +/- 0.5 compared with 3.4 +/- 0.4, P < 0.001). The AVP concentration also was greater (7.3 +/- 3.1 pmol/l) in those with Cushing's disease than in the controls (3.9 +/- 2.3 pmol/l, P < 0.005). After administration of DDAVP to the hypercortisolaemic patients, the urinary osmolality attained (718.0 +/- 200.0 mOsm/l) was still lower than that in the normal group at the end of WDT (P < 0.005). CONCLUSIONS: Patients with Cushing's disease presented higher AVP levels and smaller Uosm/Posm ratios than normal subjects. After DDAVP, the patients with Cushing's disease were unable to concentrate the urine adequately. These data suggest that the kidney shows resistance to the action of both endogenous and exogenous AVP in patients with Cushing's disease.

Adult↗

Risk factors in obese women, with particular reference to visceral fat component.

Possible associations between increased visceral fat component and serum lipid concentrations, glucose tolerance and insulinaemia (specific radioimmunoassay) were studied as risk factors for cardiovascular disease in 50 adult obese women without known diabetes and 11 lean normal women. Visceral abdominal fat areas were evaluated by computed tomography and "true" insulin concentrations. Diabetes was observed in 6 obese women (12%) and impaired glucose tolerance in 13 (26%). In obese women, visceral fat area correlated significantly with VLDL-cholesterol, triglycerides, and systolic and diastolic blood pressure, whereas subcutaneous area correlated negatively with cholesterol and LDL-cholesterol. Insulinaemia was not increased in visceral obesity nor correlated with other risk factors. An association between increased visceral fat accumulation, dyslipidaemia and increased diastolic blood pressure was observed, but no significant correlations were noted between fasting "true" insulin or insulin response on an oral glucose tolerance test and intra-abdominal fat areas or dyslipidemia. The gender of the patients could have been an important factor in these last observations.

Adipose Tissue↗