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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Intraperitoneal administration of Propionibacterium acnes in CD-1 mice was associated with the reduction in number of insulin receptors in peritoneal macrophages (M phi), and with elevated levels of insulin in plasma and the peritoneal cavity. When insulin levels returned to normal, insulin receptors in P. acnes-M phi were still reduced. Insulin appears to contribute significantly to the down-regulation of the M phi-insulin receptors during the early stage of activation. Other biologically active substances released during M phi activation might assume greater influence on insulin resistance in activated M phi at a later stage. The induction of transient
hyperinsulinemia
in P. acnes-treated mice might be attributed to the effect of concurrently elevated interleukin-1 (IL-1) released in the early course of M phi activation.
Mol
Cell Endocrinol 1987 Mar
PMID:Down-regulation of insulin receptors in Propionibacterium acnes-activated macrophages in the mouse. 355 66
Hepatic plasma membranes of female obese mice C57 BL-6 orl ob/ob (ob/ob mice) completely lack vasopressin (VP) receptors of the V1 type whereas kidney VP receptors are normally expressed and functionally coupled to adenylate cyclase. To discover if these alterations are linked to a genetic defect of the V1 receptor, we have studied the binding of VP on liver and kidney membranes of two other models, female diabetic mice C57 BL-6 orl db/db (db/db mice) and female Zucker rats Fatty/orl fa/fa (fa/fa rats), which exhibit different temporal pattern of obesity,
hyperinsulinemia
and insulin resistance. In addition, since VP is known to exert its vascular response through stimulation of V1 receptors, we have studied the reactivity of VP of isolated tail artery in the three different models, ob/ob and db/db mice and fa/fa rats, and in their respective controls. In all cases, VP kidney receptors and VP vascular reactivity are normal. db/db mice exhibit a marked decrease in hepatic VP receptors whereas a 50% decrease was observed in 32 week fa/fa rats. Angiotensin II and prazosin binding sites are still present as well as the adenylate cyclase response to glucagon. These results suggest that the specific alteration in liver VP receptors is not related to a defect in V1 receptor genetic expression but is specific for liver and appears to parallel the level of
hyperinsulinemia
and/or insulin resistance.
Mol
Cell Endocrinol 1984 Dec
PMID:Reduction in hepatic but not in renal and vascular vasopressin receptor number in hyperinsulinemic mice and rats. 609 84
Studies were performed to examine the effects of various fractions of pineal gland origin upon rates of immunoreactive insulin release during short-term incubations of pancreatic islets from pinealectomized rats. Fractions of cerebral cortex were employed in control incubations. An ultrafiltrate of pineal extracts containing materials of molecular weight less than or equal to 1000 daltons stimulated insulin release while fractions of greater molecular weight were without effect. The stimulation of insulin release observed with the lower molecular weight pineal fraction was seen with both nonstimulatory (2 mM) and stimulatory (10 and 30 mM) medium glucose concentrations, but was abolished in the presence of 2,4-dinitrophenol (200 microM). Upon further fractionation of the low molecular weight pineal extract, fractions I (estimated molecular weight range 700-1000 daltons) and 11 (estimated molecular weight range 180-700 daltons) exhibited comparable stimulatory effects upon islet insulin release: similar effects were observed with cerebral cortical fractions in these molecular weight ranges. However, pineal fraction III (estimated molecular weight range less than 180 daltons) exhibited a striking inhibitory effect upon rates of insulin release compared to cerebral cortical fraction III. Potassium, dopamine, norepinephrine and epinephrine concentrations in both pineal and cortical tissue fractions were similarly low. We conclude that insulinotropic constituent(s) of similar molecular weight occur in pineal gland and cerebral cortex, and that the pineal insulinotropic activity stimulates active insulin secretion by the islets independently of concomitant stimulation by glucose; however, lower molecular weight insulinostatic constituent(s) are notable only in the pineal. It is suggested that mild
hyperinsulinemia
seen in pinealectomized rats under some circumstances may occur as a result of loss of the pineal insulinostatic factor(s).
Mol
Cell Endocrinol
PMID:Low molecular weight pineal and cerebral fractions affecting insulin secretion in vitro. 675 98
The incidence of coronary artery disease is significantly higher in men than in women, at least until menopause. This gender difference could be explained by the action of sex steroids on the lipoprotein profile. In prepubertal children, high-density lipoprotein (HDL) cholesterol and triglyceride levels are similar between sexes, while adult men have generally lower HDL cholesterol and higher triglyceride levels than premenopausal adult women. Most cross-sectional studies have reported that sex hormone binding globulin (SHBG) and testosterone levels correlate positively with HDL cholesterol levels between sexes. Thus SHBG by modulating the balance in the biodisposal of testosterone and estradiol, might have a profound effect on the risk of cardiovascular disease. However, adjustment for body weight and body fat distribution weakens the association between SHBG, testosterone and HDL cholesterol. The negative correlation of fasting insulin with SHBG and HDL cholesterol levels in both sexes, and some evidence that insulin is an inhibitor of SHBG production in vitro, has suggested that
hyperinsulinism
might negatively regulate SHBG and HDL levels. It remains to be determined whether the inverse relationship between SHBG and insulin levels is coincidental or has a causal effect on the increase of atherosclerosis. Decreased SHBG has been shown to be predictive of the incidence of non-insulin-dependent diabetes mellitus in women but not in men, and of subsequent development of cardiovascular disease and overall mortality in postmenopausal women. SHBG is an index of androgenism in women and of insulin-resistance in both sexes, and might be useful in epidemiological studies of cardiovascular risk. However, in men, SHBG is not predictive of the occurrence of cardiovascular disease. Whether SHBG might have an intrinsic protective effect on the arterial wall through SHBG-receptors is still highly speculative.
J Steroid Biochem
Mol
Biol 1995 Jun
PMID:Interrelations between sex hormone-binding globulin (SHBG), plasma lipoproteins and cardiovascular risk. 762 11
A gene for autosomal recessive familial
hyperinsulinism
(HI) (OMIM: 256450), a neonatal metabolic disease characterized by inappropriate insulin secretion in the presence of severe hypoglycemia, was recently mapped to a 6.6 cM interval between the markers D11S926 and D11S928 on chromosome 11p in 15 families (1). In the current study we evaluated six additional families and five new markers, and further localized the gene between D11S419 and D11S1310. Using genotype data from CEPH Version 7 and data generated from this study, this region was estimated to be 0.8 cM in length. Significant linkage disequilibrium between markers and the HI gene was observed over a region of 10.3 cM (11 pter-D11S926-D11S1308-11pcen) for Ashkenazi Jewish chromosomes. Haplotype analysis showed that 12 of 36 HI chromosomes, versus one of 36 non-HI chromosomes, bore a specific haplotype for D11S419-D11S902-D11S921 (p < 0.0007), strongly suggesting a founder effect in this ethnic group.
Hum
Mol
Genet 1995 May
PMID:Recombinant mapping of the familial hyperinsulinism gene to an 0.8 cM region on chromosome 11p15.1 and demonstration of a founder effect in Ashkenazi Jews. 763 48
The mitochondrial FAD-linked enzyme glycerophosphate dehydrogenase plays a key role in the pancreatic B-cell glucose sensing device. In the present study, the activity of this enzyme was examined in islets of fa/fa rats in which inherited diabetes mellitus is associated with obesity,
hyperinsulinism
and severe insulin resistance. The specific activity of both FAD-linked glycerophosphate dehydrogenase and glutamate dehydrogenase were decreased in islet and liver homogenates prepared from fa/fa, as compared to Fa/Fa, rats, this coinciding with a low ratio between glutamateoxalacetate and glutamate-pyruvate transaminase activity in both islet and liver extracts, islet hyperplasia,
hyperinsulinemia
and hepatic steatosis in the hyperglycemic fa/fa rats. It is speculated that a low activity of FAD-linked glycerophosphate dehydrogenase in the pancreatic B-cell may participate to the perturbation of glucose homeostasis in fa/fa rats, like in other animal models of non-insulin-dependent diabetes mellitus.
Mol
Cell Biochem 1994 Jun 29
PMID:Impaired FAD-glycerophosphate dehydrogenase activity in islet and liver homogenates of fa/fa rats. 783 41
The insulin-stimulated cation channel previously identified in patch-clamped muscle preparations is here shown to be responsible for bulk Na+ entry into the cell. The mainly Na+ current of the channel was shown to be accompanied by an inhibitory Ca2+ component responsible for oscillations. Here, using quantitative fluorescence imaging of Fura-2- and SBFI-loaded soleus muscle, we measure changes in [Na+]i and [Ca2+]i related to channel function.
Insulin increased
[Na+]i and [Ca+]i in a transient spike of < 1-min duration. There was a momentary dip in [Na+]i related to inhibition of the channel by the Ca2+ spike, and changes in external Ca2+ were shown to alter [Na+]i via the cation channel, all effects being blocked by the specific channel inhibitor mu-conotoxin, but not by tetrodotoxin. The [Ca2+]i spike could also be induced by 8-bromo cyclic-guanosine 5'-monophosphate, an analogue of the channel-activator cyclic-guanosine 5'-monophosphate (cGMP). In addition it was noted that insulin reduced the [Ca2+]i rise upon subsequent muscle depolarization by a factor of 3.5. Insulin could be substituted with phorbol ester for the same effect and HA1004, a protein kinase inhibitor, blocked the reduction.
Mol
Biol Cell 1994 Apr
PMID:An insulin-sensitive cation channel controls [Na+]i via [Ca2+]o-regulated Na+ and Ca2+ entry. 805 88
Isolated hepatocytes from obese Zucker rats showed an increased capacity for lipid synthesis measured as the incorporation of 3H2O into lipid fractions. In addition lipid synthesis from 1 mM U-14C-alanine was elevated as compared to those isolated from their lean counterparts. On these lines, the amino acid was a better lipogenic substrate than U-14C-lactate at 5 mM concentration.
Insulin increased
lipid synthesis from the amino acid in the lean animals while showed no effects on this parameter in the obese. While the hepatocytes from the lean animals used to a similar extent U-14C-alanine carbon from 14CO2 production, lipid synthesis and 14C-glycogen incorporation, those from the obese animals showed a decreased oxidation and glycogen incorporation while an augmented lipid synthesis. The total amount of the amino acid taken up by the obese animals was also significantly elevated. Conversely, the metabolic fate of U-14C-leucine was very similar between the two groups. It can be concluded that in the obese Zucker rat alanine is a very important amino acid which contributes to sustain the high liver hyperlipogenesis previously described.
Cell
Mol
Biol (Noisy-le-grand) 1993 Sep
PMID:Alanine as a lipogenic precursor in isolated hepatocytes from obese Zucker rats. 822 77
Effects of feeding sucrose rich diet supplemented with and without the insulinmimetic agent vanadate for a period of six weeks were studied in rats. Sucrose diet caused hypertriglyceridemia (140% increase),
hyperinsulinemia
(120% increase) and significant elevations in the levels of glucose (p < 0.001) and cholesterol (p < 0.05) in plasma as compared to control starch fed rats. Activities of hepatic lipogenic enzymes, ATP-citrate lyase, glucose 6-phosphate dehydrogenase and malic enzyme increased by 100-150% as a result of sucrose feeding. However, glycogen content and the activities of glycogen synthase and phosphorylase in liver remained unaltered in these animals. The plasma levels of triacylglycerols and insulin in the rats fed on vanadate supplemented sucrose diet were 65% and 85% less, respectively as compared to rats on sucrose diet without vanadate. The concentrations of glucose and cholesterol in plasma and the activities of lipogenic enzymes in liver did not show any elevation in sucrose fed rats when supplemented with vanadate. These data indicate that the sucrose diet-induced metabolic aberrations can be prevented by the insulin-mimetic agent, vanadate.
Mol
Cell Biochem 1993 May 12
PMID:Effects of vanadate administration on the high sucrose diet-induced aberrations in normal rats. 835 Aug 66
Studies to be reviewed were stimulated by the clinical observation, albeit controversial, that diabetic pregnancy may be associated with lower serum oestrogen levels than nondiabetic pregnancy. Pregnant diabetic women are usually intensively treated with insulin to maintain euglycemia, frequently resulting in peripheral
hyperinsulinemia
. The placenta, which is the primary source of oestrogens during pregnancy, would be exposed to this elevation in circulating insulin levels. Similarly, insulin-like growth factors (IGFs), which are synthesized and secreted by placental tissues and could influence placental function in an autocrine or paracrine fashion, may be elevated in diabetic pregnancy. We will review studies, which show that (i) insulin, insulin-like growth factor-I (IGF-I), and -II inhibit the aromatase activity of human cytotrophoblasts, (ii) these peptides can inhibit aromatase by activation of their respective receptors, and (iii) the potency of IGF-II in suppressing aromatase greatly exceeds that of either insulin or IGF-I. Finally, evidence will be reviewed, which suggests that inositol-glycan mediators ('second messengers') serve as the signal transduction system for insulin's inhibition of aromatase activity. Hence, placental exposure to increased concentrations of insulin and/or IGFs in the pregnant diabetic woman may result in inhibition of aromatase activity and decreased serum oestrogen levels.
J Steroid Biochem
Mol
Biol 1993 Mar
PMID:Regulation of the aromatase activity of human placental cytotrophoblasts by insulin, insulin-like growth factor-I, and -II. 847 59
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