Search results for " METABOLISM"
showing 10 items of 4843 documents
Calcium inhibits ovarian steroidogenesis in the blowfly Phormia regina.
2002
1479-6805 0022-0795; Calcium is frequently involved in the stimulation of steroidogenesis in gonads and endocrine glands, generally in association with cAMP. However, our present observations show that it has the opposite effect in the ovary of the blowfly Phormia regina. Our in vitro experiments first showed that extracellular calcium does not play a role during the stimulation of steroidogenesis in fly ovaries; indeed steroidogenesis was activated in vitro as efficiently in a medium with or without calcium, either by pharmacological compounds mimicking cAMP signaling or by active brain extracts. When calcium was experimentally introduced into biosynthetic cells by ionophores or liberated …
Induction of the adrenoleukodystrophy-related gene (ABCD2) by thyromimetics.
2009
X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder caused by mutations in the ABCD1 (ALD) gene. The ABCD2 gene, its closest homolog, has been shown to compensate for ABCD1 deficiency when overexpressed. We previously demonstrated that the ABCD2 promoter contains a functional thyroid hormone response element. Thyroid hormone (T3) through its receptor TRbeta can induce hepatic Abcd2 expression in rodents and transiently normalize the VLCFA level in fibroblasts of Abcd1 null mice. In a therapeutic perspective, the use of selective agonists of TRbeta should present the advantage to be devoid of side effects, at least concerning the cardiotoxicity associated to TRalpha activation. I…
In vitro free radical scavenging capacity of thyroid hormones and structural analogues.
2001
It was reported that thyroid hormones decreased Cu(2+)-induced low-density lipoprotein (LDL) oxidation in vitro. Here, we investigated free radical scavenging capacities of thyroid hormones (3,5,3'-tri-iodo-L-thyronine (T(3)), thyroxine (T(4)) and 3,3',5'-tri-iodo-L-thyronine (rT(3))) and structural analogues (L-thyronine (T(0)), 3,5,3'tri-iodothyroacetic acid (TA(3)) and 3,5,3',5'-tetra-iodothyroacetic acid (TA(4))), using three different models of free radical generation. T(0), T(3) and TA(3) slowed down production of conjugated diene and thiobarbituric acid-reactive substances during LDL oxidation by 2,2'-azobis-[2-amidinopropane] (water-soluble), whereas rT(3), T(4) and TA(4) had practi…
Lipoic Acid Improves Nerve Blood Flow, Reduces Oxidative Stress, and Improves Distal Nerve Conduction in Experimental Diabetic Neuropathy
1995
OBJECTIVE To determine whether lipoic acid (LA) will reduce oxidative stress in diabetic peripheral nerves and improve neuropathy. RESEARCH DESIGN AND METHODS We used the model of streptozotocin-induced diabetic neuropathy (SDN) and evaluated the efficacy of LA supplementation in improving nerve blood flow (NBF), electrophysiology, and indexes of oxidative stress in peripheral nerves affected by SDN, at 1 month after onset of diabetes and in age-matched control rats. LA, in doses of 20, 50, and 100 mg/kg, was administered intraperitoneally five times per week after onset of diabetes. RESULTS NBF in SDN was reduced by 50% LA did not affect the NBF of normal nerves but improved that of SDN i…
Predictors of Progression in Hypertensive Renal Disease in Children
2004
In hypertensive renal disease in children, several risk factors influence the development and the rate of progression of renal damage, including blood pressure levels, proteinuria, lipid disorders, and genetic differences. The impact of blood pressure on renal structures, the most important of the factors, depends not only on blood pressure levels, but also on the persistence of the blood pressure levels over time, mainly during the hours when the patient is resting or sleeping. Abnormal circadian variability is frequently observed in patients with renal damage, and nocturnal blood pressure reduction should be a major therapeutic objective to protect against a decline in renal function. Pro…
Influence of long-term postmenopausal hormone-replacement therapy on estimated structural bone strength: A study in discordant monozygotic twins
2010
Although postmenopausal hormone-replacement therapy (HRT) is known to prevent fractures, knowledge on the influence of long-term HRT on bone strength and its determinants other than areal bone mineral density is scarce. This study used a genetically controlled design with 24 monozygotic female twin pairs aged 54 to 72 years in which one cotwin was using HRT (mean duration 8 years) and the other had never used HRT. Estimated bone strength, cross-sectional area, volumetric bone mineral density, bone mineral mass, and cross-sectional density and mass distributions were assessed in the tibial shaft, distal tibia, and distal radius with peripheral computed tomography (pQCT). In the tibial shaft,…
Control of ovarian steroidogenesis by insulin-like peptides in the blowfly (Phormia regina).
2004
0022–0795/04/0181–147; This study investigated the ability of insulin and of insect insulin-like peptides (ILPs) to stimulate ovarian steroidogenesis in the blowfly Phormia regina. Bovine insulin was active on ovaries isolated in vitro, which showed an age-dependent sensitivity; this peptide progressively stimulated steroidogenesis in ovaries isolated from the third day after adult molt, but not in younger ones, and had maximal activity after the fifth day. This stimulatory effect was observed equally from females reared in the presence or in the absence of males, excluding a regulatory effect of mating. The mode of action of insulin in blowflies did not involve cAMP, but triggered a specif…
Effect of CYP1A1 Gene Polymorphisms on Estrogen Metabolism and Bone Density
2004
UNLABELLED: In this study, we evaluated the effect of polymorphisms of the CYP1A1 gene, linked to hormone-related cancers, on estrogen metabolism and BMD. We found that variants carrying the A allele (CA and AA) for the C4887A polymorphism have a significantly higher degree of estrogen catabolism and lower femoral BMD. INTRODUCTION: Polymorphisms of the CYP1A1 gene, one of the key enzymes that metabolize estrogen, have been linked with hormone-related cancers. We investigated the impact of these polymorphisms on estrogen metabolism and BMD, which is another hormone-dependent health issue. MATERIALS AND METHODS: One hundred seventy postmenopausal women (mean age, 63.5 +/- 0.6 years) particip…
Duration of breastfeeding as a risk factor for vertebral fractures
2014
Abstract Purpose Among the risk factors for osteoporosis and fractures, gynecological history (fertile period, parity and breastfeeding) play an important part. Changes in calcium metabolism to enable an adequate mineral transfer to the milk have a prominent role in bone loss during breastfeeding. Data on the influence of breastfeeding in postmenopausal osteoporosis are inconsistent. The aim of the present study was to identify any association between duration of breastfeeding and vertebral fractures in postmenopausal women. Methods All patients underwent the following tests: bone mineral density measurements of the lumbar spine (L1–L4) and the total and femoral neck using dual-energy X-ray…
Diagnostic efficacy of the fluorometric determination of enzyme activity for Pompe disease from dried blood specimens compared with lymphocytes-possi…
2009
Pompe disease is a rare, autosomal-recessive disorder which results from a defect in the lysosomal enzyme acid alpha-glucosidase (GAA). The onset of this disease is highly variable, with infantile types being the most severe. Traditionally, lymphocytes, fibroblasts or muscle biopsies were necessary for enzyme activity measurement, because these materials do not express maltase-glucoamylase (MGA) that interferes with the assay. Recently, acarbose was found to inhibit MGA activity selectively, so that dried blood became accessible for GAA assessment.To evaluate the diagnostic efficacy of GAA measurement in dried blood specimens (DBSs) in comparison with lymphocytes. If DBSs provided reliable …