UMLS:C0011849 - FACTA Search

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Query: UMLS:C0011849 (diabetes)
277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The insulin-mimetic effects of vanadate in preventing the increase in the level and activity of several P450 proteins in streptozotocin-diabetic rats were examined, in order to extend knowledge of the insulin-like actions of vanadate from glucose metabolism to P450-dependent metabolism. The diabetic state caused by the pancreatic beta cell toxin streptozotocin results, like the diabetes of genetic origin, in major alterations in the expression of P450 isozymes. We focused our attention on the P450III and P450I isoforms, known to be altered during the onset of diabetes. We found an increase in P450IIIA1-linked erythromycin demethylase activity (to about double the control level) and in the relative levels of P450III and P450I isozymes after 2 weeks of uncontrolled diabetes. These parameters were not different from control values in rats given vanadate in drinking water for 2 weeks after streptozotocin administration or in insulin-treated rats. In summary, vanadate appears to exert insulin-mimetic actions on the P450III and P450I family proteins that have a key role in cytochrome P450-dependent metabolism.
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PMID:Insulin-mimetic effects of vanadate in preventing the increase of P450IIIA and P450IA subfamily proteins in streptozotocin-diabetic rats. 811 Oct 71

Effects of thyroid hormone treatment on renal P450 expression in the diabetic rats were investigated. Diabetes produced by streptozotocin induced CYP4A2 and P450 K-2 (similar form with CYP2C23) but not P450 K-4 (similar form with CYP4A8) and induced lauric acid hydroxylation activity. The serum thyroid hormone level was decreased with diabetes. Treatment of diabetic rats with thyroid hormone (T3) as well as with insulin reversed the increase in the levels of CYP4A2 and P450 K-2. Thyroidectomy also induced CYP4A2 and P450 K-2 in the rat kidney. The increase was reversed by treatment of thyroidectomized rats with T3. These findings suggest that expression of CYP4A2 and P450 K-2 in rat kidney is suppressively regulated by thyroid hormone and the decrease in thyroid hormone level in the diabetic state affects the levels of CYP4A2 and P450 K-2.
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PMID:Regulation of renal cytochrome P450s by thyroid hormone in diabetic rats. 827 52

In order to analyse further the pathophysiology of pentamidine effects on blood glucose regulation, the following experimental models were established in rats: impairment of the renal function, bile duct ligation, inhibition of the P450 cytochrome enzyme system. In otherwise intact rats, 7.5 mg/day pentamidine was well tolerated whereas doses of 15 mg/day induced severe, relapsing and eventually lethal hypoglycaemia within a few days. Induction of a renal insufficiency of graded severity by treatment with gentamycin, subtotal nephrectomy and total bilateral nephrectomy resulted in repetitive, severe (sometimes lethal) hypoglycaemia, alternating with hyperglycaemia, glucosuria and ketonuria in pentamidine-treated rats (7.5 mg/d). No long-standing insulin-dependent diabetes was observed. In the dysglycemic animals, plasma insulin levels were inappropriate to the concomitant glycaemia; no stimulation was obtained by i.v. glucose. Glucagon levels were higher than normal, suppressible by i.v. glucose, responsive to IV arginine and to hypoglycaemia. Dysglycemic events were more frequent and marked in the rats with the most severe renal functional derangement. They were more frequent in the rats treated with pentamidine mesylate than in those treated with the isethionate salt. Control uremic rats (free of pentamidine) remained euglycaemic. The islets of Langerhans displayed severe vascular congestion and degranulation and necrosis of the B cells, while the non B cells (and particularly the A cells) were intact. Exocrine pancreatitis was occasionally observed in the most severely uremic rats. In contrast with uremic rats, neither surgical ligation of choledocus, nor treatment by P450 cytochrome inhibitors (particularly ketoconazole) precipitated dysglycaemia in the pentamidine-treated rats. These experimental data: 1) strengthen the concept of inappropriate insulin release from pentamidine-lesioned islet B cells due to pentamidine accumulation; 2) indicate a predominant role for renal insufficiency in determining the accumulation of this drug; 3) emphasize the clinical importance of renal insufficiency as a risk factor for pentamidine-induced dysglycaemia. Association with ketoconazole does not appear to be a risk factor.
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PMID:Pentamidine-induced dysglycaemia: experimental models in the rat. 833 59

Hepatic microsomal cytochrome P450s, which are involved in the metabolism of drugs, hormones, prostaglandins and fatty acids, change when animals develop diabetes. We studied changes in cytochrome P450 isozymes in both hepatic and renal microsomes of rats with diabetes caused by streptozocin, and compared the results with changes in catalytic activities in the microsomes. In hepatic microsomes of diabetic rats, the amount of cytochrome P450 2E1, an acetone-inducible isozyme, was two and a half times that of control rats, and that of P450 4A2, a major renal isozyme, was three times that in the controls. The amounts of cytochrome P450s 2A1, 2C6, 2C7, 3A2 and 4A3 increased in hepatic microsomes of diabetic rats, and P450 2C11 decreased. Treatment with insulin restored these to the levels in the controls. The catalytic activities of aniline hydroxylation, 7-ethoxycoumarin O-dealkylation, testosterone 2 beta, 6 beta, 7 alpha, and 16 beta-hydroxylation, and omega-, (omega-1)-hydroxylation of lauric acid were high in the hepatic microsomes of diabetic rats, and testosterone 2 alpha and 16 alpha-hydroxylation activities were low. In renal microsomes of diabetic rats, cytochrome P450s 2E1, 4A2 and K-4 were induced, and omega- and (omega-1)-hydroxylation activities were high. These changes were reversed by insulin treatment. The induction and suppression of cytochrome P450 isozymes in diabetic rats were consistent with the changes in the catalytic activities. In both hepatic and renal microsomes, P450s 2E1 and 4A2 were induced, altered metabolism of ketones and fatty acids in diabetes may contribute to these changes.
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PMID:Changes in amounts of cytochrome P450 isozymes and levels of catalytic activities in hepatic and renal microsomes of rats with streptozocin-induced diabetes. 836 36

1. Male Wistar rats were rendered diabetic by the administration of a single intraperitoneal dose of streptozotocin; the levels of the xenobiotic-inducible P450 proteins were determined in the lung and kidney using diagnostic substrates and immunoblotting employing polyclonal antibodies. The glutathione conjugation system in the cytosol of these tissues was also investigated. 2. The onset of insulin-dependent diabetes did not influence the O-dealkylations of methoxyresorufin, ethoxyresorufin and pentoxyresorufin in either kidney or lung. 3. Lauric acid hydroxylase activity, however, was induced in the kidney but no activity was detectable in the lung. Immunoblot analysis of kidney microsomes using antibodies to P4504A1 revealed the presence of two bands, both of which were clearly inducible in diabetes. In pulmonary microsomes a single faint band was detected which also appeared to be higher in the diabetic rats. 4. Aniline p-hydroxylase activity was not detectable in the kidney, but activity was measurable in the lung and was suppressed in diabetes. Immunoblot analysis of pulmonary microsomes using antibodies to P4502E1 immunodetected a single band which was suppressed in diabetes. In the kidney microsomes a single band was also detected which was, however, markedly elevated in diabetes. 5. Glutathione S-transferase activity was modestly higher in the kidney, but not lung, of the diabetic animals. Glutathione reductase and total glutathione levels were not influenced by the presence of diabetes. 6. It is concluded that streptozotocin-induced insulin-dependent diabetes modulates extrahepatic P450 proteins, the effect being both tissue- and isoform-specific.
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PMID:Extrahepatic expression of P450 proteins in insulin-dependent diabetes mellitus. 855 87

Reproductive dysfunction in the diabetic female rat is associated with impaired folliculogenesis, reduced corpus luteum progesterone output, and spontaneous abortion. The underlying mechanism for reduced steroid production remains unresolved. In this study we examined whether or not diabetes alters levels of P450 side-chain cleavage enzyme (P450scc), 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), or the cholesterol transport proteins, steroidogenic acute regulatory (StAR) protein and sterol carrier protein-2 (SCP2), leading to lower progesterone levels and pregnancy loss. Rats (Day 3 pregnant) received an injection of streptozotocin (STZ, 60 mg/kg; i.v.) to induce a diabetic state; P450scc, 3 beta-HSD, and SCP2 were examined by Western and Northern blot analysis in ovarian tissue 12 days after injection of STZ (diabetic rats, n = 12) or vehicle (nondiabetic rats, n = 12). Serum progesterone, triglyceride, and beta-hydroxybutyrate (beta-HBA) levels were also examined. Results indicate that diabetic rats that aborted (diabetic-fetus [Ft], n = 6) had significantly lower progesterone levels (7.04 +/- 2.6 ng/ml; p < 0.004) than nondiabetic animals (108.6 +/- 5.15 ng/ml) and diabetic +Ft animals (74.3 +/- 8.9 ng/ml, n = 6). Western blot analysis of ovarian P450scc and 3 beta-HSD in the nondiabetic rats and the diabetic rats with fetuses indicated no significant difference. In contrast, ovaries from diabetic animals without fetuses had significantly lower SCP2 levels (p < 0.017) compared to controls. Concomitant with the reduction in SCP2, a 58-kDa SCP2-immunoreactive protein, referred to as sterol carrier protein-X (SCPx), increased significantly (p < 0.001). The C-terminal sequence of SCPx is identical to SCP2, while its N-terminal region is homologous with 3-oxoacyl coenzyme A thiolase, an enzyme involved in fatty acid metabolism. Increased SCPx expression coincided with increased serum triglyceride and beta-HBA levels, suggesting that the enhanced SCPx level may coincide with an ovarian shift to fatty acid metabolism. When SCPx steady-state mRNA levels were measured using an SCPx-specific riboprobe (280-bp protected fragment) in a ribonuclease protection assay, ovarian SCPx mRNA levels in the diabetic animals were increased 4.2-fold compared to control SCPx mRNA levels. Ovarian StAR mRNA levels were increased slightly in the diabetic animals, and ovarian P450scc and 3 beta-HSD mRNA levels were increased 3-fold in the diabetic animals that aborted relative to the nondiabetic animals and the +Ft diabetic animals. Results of this study confirm that SCPx mRNA levels are elevated following diabetes onset and that StAR, P450scc, and 3 beta-HSD mRNA levels do not correspond with the reduced steroid hormone profile associated with diabetes. These results are concordant with the possibility that reduced steroid levels in the diabetic animals reflect a loss of SCP2-mediated cholesterol transport capacity as SCPx/3-oxoacyl coenzyme A thiolase expression is enhanced.
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PMID:Altered ovarian sterol carrier protein expression in the pregnant streptozotocin-treated diabetic rat. 879 56

The acute and chronic effects of streptozotocin diabetes on kidney and liver microsomal monooxygenases were studied using hamsters 2 days and 6 weeks following treatment with the diabetogen, respectively. Acute diabetes increased aniline hydroxylation and N-nitrosodimethylamine demethylation, decreased pentoxyresorufin O-dealkylation, without affecting benzo(a)pyrene hydroxylation and 7-ethoxycoumarin O-deethylation in kidney and liver microsomes. The effects of chronic diabetes on the microsomal monooxygenases were similar to the effects of acute diabetes, except that the chronic diabetic condition markedly decreased benzo(a)pyrene and 7-ethoxycoumarin oxidations in kidney microsomes. Total cytochrome P450 content and NADPH-cytochrome P450 reductase activity in kidney and liver microsomes of the diabetic hamsters were similar to the controls. Gel electrophoresis of microsomes from control and streptozoptocin treated hamster tissues revealed that diabetes enhanced the intensity of protein band(s) in the P450 molecular weight region. Immunoblotting of microsomal proteins showed that acute and chronic streptozotocin diabetes induced proteins immunorelated to P450s 2E1 and 1A in kidney and liver. In marked contrast, the acute and chronic diabetic conditions decreased the level of a P450 2B-immunorelated protein(s) in kidney and liver. The present study demonstrates that acute and chronic streptozotocin diabetes has the ability to induce P450 2E1 and 1A and suppress P450 2B in hamster kidney and liver and that the hamster monooxygenase responds to diabetes differently from the rat enzyme.
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PMID:Induction and suppression of renal and hepatic cytochrome P450-dependent monooxygenases by acute and chronic streptozotocin diabetes in hamsters. 882 78

Understanding the molecular regulation of the sulfotransferases is important because these enzymes are essential to a number of critical biological processes. Sulfotransferase expression clearly plays a role in xenobiotic detoxication, carcinogen activation, prodrug processing, cellular signaling pathways, and the regulation of intratissue active androgen and estrogen levels. Although cytosolic sulfotransferases are present in the gut, adrenal, kidney, lung, skin, brain, and other extrahepatic tissues, the basis for the molecular regulation of this complicated gene family has been best characterized in the rat liver, where sulfotransferase levels are relatively abundant. Advances in genomic cloning and in the molecular characterization of individual sulfotransferase cDNAs have inspired new insights into the mechanisms involved in sulfotransferase gene regulation. In particular, the hypothalamic-pituitary-gonadal-adrenocortical axis appears to play a significant role in the regulation of individual sulfotransferase genes. The molecular signals that fluctuate with developmental age, gender, and the occurrence of systemic endocrinopathies also influence sulfotransferase gene expression. For example, diabetes, which disrupts glucose and ketone homeostasis, insulin sensitivity, gonadal and neuroendocrine hormone balance, protein kinase C isoform expression, and P450 metabolism, also disturbs hepatic sulfotransferase gene expression. What role does sulfotransferase expression play in target organ toxicity? Do xenobiotic-mediated changes in sulfotransferase expression compromise detoxication? Does deregulated sulfotransferase expression during development lead to birth defects by perturbing the delicate balance of active hormone levels in fetal tissues? Do conditions of glucocorticoid excess, such as stress or high-dose glucocorticoid therapy induce sulfotransferase expression and place toxicant and carcinogen bioactivation systems in overdrive? This review will summarize our current understanding of the molecular and cellular regulation of the major rodent cytosolic sulfotransferases. Only by thoroughly dissecting the regulation of this important multigene family in rodent liver, where sulfotransferase expression is most abundant, can we begin to focus on more pressing questions concerning the role of the sulfotransferases in the genesis of endocrinopathies and cancer in humans.
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PMID:Regulation of expression of the rodent cytosolic sulfotransferases. 903 52

The crucial role of glucocorticoids in obesity and insulin resistance and the actions of the OB protein leptin on the hypothalamic-pituitary-adrenal (HPA) axis suggest that there is an important interaction of leptin with the glucocorticoid system. Therefore, we designed a study to test the effect of leptin directly on adrenocortical steroidogenesis. Primary cultures of bovine adrenocortical cells were incubated with increasing concentrations (10-1,000 ng/ml) of recombinant mouse leptin for 24 h, and the effects of leptin on basal and ACTH-stimulated cortisol secretion were determined. The accumulation of P450 17alpha mRNA following incubation with ACTH (10 nmol/l) and leptin (10-1,000 ng/ml) was analyzed by Northern blot. Adrenocortical cells were characterized by immunohistochemical staining for 17alpha-hydroxyprogesterone. Leptin (10-1,000 ng/ml) inhibited basal and ACTH-stimulated cortisol release. At a concentration that occurs in obese individuals in vivo (100 ng/ml), it reduced basal cortisol secretion to 52.7 +/- 37% (mean +/- SE). The rise in cortisol secretion following maximal ACTH stimulation (10 nmol/l) was blunted to 55.2 +/- 27%. At more physiological concentrations of ACTH (0.1 nmol/l), the inhibition of cortisol release by coincubation with low doses of leptin (10 ng/ml) was even more pronounced, leading to a reduction to 32.8% (1,248 +/- 134 vs. 410 +/- 157 nmol/l). Addition of OB protein (10-1,000 ng/ml) led to a dose-dependent reduction of ACTH-stimulated cytochrome P450 17alpha mRNA accumulation (from 80 to 45%), suggesting that leptin regulates adrenal steroidogenesis at the transcriptional level. These data clearly demonstrate that leptin inhibits cortisol production in adrenocortical cells and therefore appears to be a metabolic signal that directly acts on the adrenal gland.
Diabetes 1997 Jul
PMID:Evidence for a novel peripheral action of leptin as a metabolic signal to the adrenal gland: leptin inhibits cortisol release directly. 920 Jun 62

This paper approaches the hypothesis that fatty acids contribute to hypertension by examining possible interactions of nonesterified fatty acids with renal pressure-natriuresis, peripheral vascular resistance, and the central nervous barostat, three loci where long-term regulation of blood pressure is probably controlled. By inhibiting aldosterone secretion, nonesterified fatty acids may lower blood pressure by facilitating pressure-natriuresis. Oxygenated metabolites of fatty acids appear to stimulate aldosterone secretion. In different experimental situations, fatty acids either constrict or dilate arteries. There is no evidence of an effect of fatty acids on the central nervous barostat, but they do sensitize peripheral vessels to alpha-adrenergic stimuli. Obesity and diabetes are marked by increased incidence of hypertension, and elevated levels of fatty acids or their P450 oxygenated metabolites may contribute to this association. Drugs that influence plasma fatty acids, like heparin, do not have reproducible effects on blood pressure. Experimental evidence suggests but does not prove that nonesterified fatty acids can affect the long-term set-point of blood pressure.
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PMID:Nonesterified fatty acids in the pathogenesis of hypertension: theory and evidence. 925 Jun 9

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