Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Adipocytes were isolated from the interscapular brown fat of male rats maintained at 21 degrees C. These animals were controls, streptozotocin-diabetics or 2-day insulin-treated diabetics. 2. With adipocytes from diabetic animals, maximum rates of noradrenaline-stimulated O2 uptake were decreased by 58%, and the Bmax. of [3H]GDP binding to mitochondria was decreased by 55%. Insulin administration reversed both of these changes. 3. Streptozotocin-diabetes increased basal lipolysis in adipocytes incubated with adenosine deaminase (1 unit/ml), decreased the EC50 (concn. giving 50% of maximum effect) for noradrenaline, but did not change the maximum rate of noradrenaline-stimulated lipolysis. Except for some small differences at very low concentrations (10-100 pM), diabetes or insulin treatment did not alter the sensitivity of noradrenaline-stimulated lipolysis or O2 uptake to the inhibitory effect of N6-phenylisopropyladenosine. It is therefore concluded that the lesion(s) in thermogenesis in diabetes are not attributable to any changes in lipolysis. 4. Blood flow through interscapular brown fat, measured by accumulation of [14C]DDT [14C-labelled 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane] was increased by 2.3-fold 70 min after a single administration of insulin to diabetic rats. This treatment decreased blood flow through epididymal white fat by 58%. 5. Propranolol treatment of diabetic rats muted the ability of insulin treatment to increase the maximum rate of noradrenaline-stimulated O2 uptake, suggesting that this action of insulin may be a secondary one rather than a direct effect of the hormone on the adipocytes.
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PMID:Factors influencing the altered thermogenic response of rat brown adipose tissue in streptozotocin-diabetes. 327 24

The sensitivity to lipolytic agents is altered in diabetic vs. control animals. Because of its role as a diabetogenic hormone and its ability to elicit lipolysis, GH was studied in isolated fat cells (IFC) from control and streptozotocin-diabetic (STZ-DM) rats. IFCs from the epididymal fat of 150 to 200-g normal and STZ-DM Holtzman rats were prepared by collagenase digestion. Lipolysis was measured by glycerol release after either incubation or perifusion with the following concentrations: epinephrine (EPI), 0.01-0.1 microM; theophylline, 0.01-1.0 mg/ml; adenosine deaminase (ADA), and bovine GH (bGH), 0.01-1.0 microgram/ml. Rats, rendered diabetic by STZ (65 mg/kg), were used on day 3. In a dose-response study comparing glycerol release from control and STZ-DM IFC, IFC were preincubated with 1.0 microgram/ml bGH and then incubated with varying concentrations of EPI or bGH. In STZ-DM, we noted increased lipolytic sensitivity to low concentrations of EPI or bGH. Furthermore, in perifusion, STZ-DM IFC did not require obligatory preincubation with bGH for optimal glycerol release. The addition of ADA increased glycerol release from incubated IFC (STZ-DM and controls). In both systems an enhanced lipolytic response to theophylline was seen in the presence of bGH in control and STZ-DM. It was thus concluded that IFC from normal animals do not respond to GH without preincubation. IFC from STZ-DM rats show a lipolytic response to GH without preincubation. Preincubation with GH increases the lipolytic response of IFC from STZ-DM to all lipolytic agents compared to control responses. In addition, ADA greatly enhanced lipolysis in IFC from STZ-DM compared to that in controls. Together these data demonstrate enhanced sensitivity to both lipolytic stimuli and adenosine suppression of lipolysis in IFC from STZ-DM.
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PMID:Lipolysis in diabetic adipocytes: differences in response to growth hormone and adenosine. 362 74