Metabolism: clinical and experimental
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Previous in vivo studies in cardiomyopathic hamsters suggested that the expression of vasopressin (AVP) V2 mRNA is up- regulated by angiotensin II. The present study was performed to determine whether angiotensin II plays a role in regulating the expression of AVP V2 mRNA and aquaporin-2 (AQP2) mRNA in the inner medullary collecting duct (IMCD) of the male Wistar rat. The expression of AVP V2 mRNA and AQP2 mRNA in the IMCD was measured by competitive reverse-transcriptase polymerase chain reaction (RT-PCR). ⋯ In the fifth and sixth groups of studies, we determined the direct effect of PKA and PKC on regulating the expression of V2 mRNA and AQP2 mRNA in the IMCD, respectively. Dibutryl cAMP stimulated an upregulation in the expression of V2 mRNA and AQP2 mRNA, whereas phorbol esters suppressed the expression of V2 mRNA. These results suggested that PKA stimulates and PKC suppresses the expression of V2 mRNA in the IMCD of the kidney.
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The objective of this study was to investigate the relationship between growth hormone (GH) dynamic tests (thyrotropin-releasing hormone [TRH] test and oral glucose tolerance test [OGTT]), insulin-like growth factor-I (IGF-I) plasma values, tumor size, and clinical outcome in patients with GH-secreting pituitary adenomas. Furthermore, we investigated the potential prognostic utility of the above biochemical parameters in the follow-up of patients with acromegaly. We studied 50 acromegalic patients (18 males and 32 females; mean age, 40 years; range, 16 to 69) who underwent trans-sphenoidal removal of a GH-secreting pituitary adenoma from 1990 to 1994. ⋯ Preoperatively, "controlled" patients (n = 29) had a GH paradoxical response to TRH (n = 28) and an unresponsiveness to OGTT (n = 29); 23 of them belonged to the I and II classes. Only 5 poorly controlled patients (n = 21) showed a preoperative paradoxical response to TRH and 9 had a preoperative GH partial inhibition after OGTT; 19 of them belonged to the III and IV classes. Our data suggest that in the preoperative period in acromegalic patients the simultaneous presence of a GH paradoxical response to TRH and lack of GH inhibition after OGTT is inversely related to the tumor size and therefore more likely to be restored to normal by surgical treatment.
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Comparative Study
Impaired fibrinolytic compensation for hypercoagulability in obese patients with type 2 diabetes: association with increased plasminogen activator inhibitor-1.
In patients with type 2 diabetes, fibrinolysis is considered impaired by increased plasma concentrations of plasminogen activator inhibitor (PAI)-1. However, several investigators found both coagulation and fibrinolysis to be activated in these patients. We further characterized the balance between coagulation and fibrinolysis in lean and obese patients with type 2 diabetes. ⋯ In conclusions, both coagulation and fibrinolytic systems are enhanced in lean and obese type 2 diabetic patients compared with healthy subjects. Although the degree of activation of coagulation was similar between lean and obese diabetic patients, the fibrinolytic activity was lower in obese than lean patients. Fibrinolytic compensation for hypercoagulation is incomplete in obese patients with type 2 diabetes, partly because of elevated PAI-1 in the blood.
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Clinical Trial
Efficacy and safety of the new 60-mg formulation of the long-acting somatostatin analog lanreotide in the treatment of acromegaly.
Recently, a new slow-release (SR) formulation of lanreotide (LAN) comprising 60 mg of the drug incorporated in microspheres of biodegradable polymers (SR-LAN 60) has become available. The aim of our study was to assess the effectiveness of SR-LAN 60, administered every 21 to 28 days, as well as its tolerability in the long-term treatment of acromegalic patients treated with SR-LAN 30. Twenty patients with acromegaly (10 males and 10 females) were enrolled in this open study. ⋯ In conclusion, this study shows that SR-LAN 60 treatment is able to induce a good control of circulating GH and IGF-I levels in most acromegalic patients. The first injections of SR-LAN 60 are very helpful in predicting the optimal long-term injection frequency. Patients on SR-LAN 30 can be safely and effectively shifted to SR-LAN 60.
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Although obesity is a frequent feature of type 2 diabetes mellitus (DM), many patients with type 1 DM are prone to high body mass index (BMI). We measured serum leptin concentrations in a cohort of children (n = 55) with type 1 diabetes mellitus (DM), as well as their anthropometric parameters including BMI, skin fold thickness at multiple sites, and midarm circumference. Glycemic control was assessed by blood glucose (BG) monitoring before meals, and measurement of glycated hemoglobin (HbA1c) and insulin dose/kg/d was recorded. ⋯ Multiple regression analysis showed that circulating leptin concentrations (the dependent variable) were best correlated with the mean skinfold thickness (SFT), BMI, and caloric intake/kg/d (together they explained 65% of the variability in leptin concentrations). It appears that oversubstitution by insulin and increased food intake stimulate fat synthesis and subsequently BMI. Increased appetite and BMI contribute to increased leptin secretion and explains the higher leptin levels in undercontrolled diabetic children (higher circulating HbA1c concentrations) who were oversubstituted by insulin.