bluuebunny/crossref_metadata_2025 huggingface dataset:
Aminopeptidase-A. I. cDNA cloning and expression and localization in rat tissues
Authors: Troyanovskaya Marta , Jayaraman Gomathi , Song Lijun , Healy Dennis P.
Published: December 2017

Aminopeptidase-A (APA) is an ectoenzyme that selectively hydrolyzes acidic residues from the amino terminus of oligopeptides, including biologically active [Asp1]ANG II and [Asp1]CCK-8. We sought to characterize rat APA by cDNA cloning and expression and to determine its tissue distribution by in situ hybridization and immunohistochemistry. Sequence analysis of overlapping cDNA clones isolated from rat kidney cDNA libraries indicated that the full-length cDNA encoded a 945-amino acid protein with a predicted molecular mass of 108 kDa; the size was confirmed by in vitro translation of a full-length cDNA construct. Transient transfection of the full-length cDNA construct in mammalian cells yielded a protein ∼140 kDa in size, a size that agrees with the immunoblots of APA from rat tissue and is consistent with APA being known as a glycosylated protein. Tissue APA activity and mRNA expression were highest in the kidney and ileum. Localization of APA by in situ hybridization and immunohistochemistry indicated that, with the exception of the kidney and ileum, where APA was localized to the luminal brush border of proximal tubules and enterocytes, respectively, APA was associated with either capillaries or the lining of sinusoids. Areas known to be physiological targets for ANG II, including glomeruli, the zona glomerulosa, and anterior pituitary, had high levels of APA. The localization pattern suggests that APA may subserve multiple functions, i.e., a generalized role in peptide scavenging and perhaps a more specific role in metabolism of circulating or locally produced ANG II or CCK-8.
Effects of a unique conjugate of α-lipoic acid and γ-linolenic acid on insulin action in obese Zucker rats
Authors: Peth J. Anthony , Kinnick Tyson R. , Youngblood Erik B. , Tritschler Hans J. , Henriksen Erik J.
Published: December 2017

The purpose of this study was to assess the individual and interactive effects of the antioxidant α-lipoic acid (LPA) and the n-6 essential fatty acid γ-linolenic acid (GLA) on insulin action in insulin-resistant obese Zucker rats. LPA, GLA, and a unique conjugate consisting of equimolar parts of LPA and GLA (LPA-GLA) were administered for 14 days at 10, 30, or 50 mg ⋅ kg body wt− 1 ⋅ day− 1. Whereas LPA was without effect at 10 mg/kg, at 30 and 50 mg/kg it elicited 23% reductions ( P < 0.05) in the glucose-insulin index (the product of glucose and insulin areas under the curve during an oral glucose tolerance test and an index of peripheral insulin action) that were associated with significant increases in insulin-mediated (2 mU/ml) glucose transport activity in isolated epitrochlearis (63–65%) and soleus (33–41%) muscles. GLA at 10 and 30 mg/kg caused 21–25% reductions in the glucose-insulin index and 23–35% improvements in insulin-mediated glucose transport in epitrochlearis muscle. The beneficial effects of GLA disappeared at 50 mg/kg. At 10 and 30 mg/kg, the LPA-GLA conjugate elicited 29 and 38% reductions in the glucose-insulin index. These LPA-GLA-induced improvements in whole body insulin action were accompanied by 28–63 and 38–57% increases in insulin-mediated glucose transport in epitrochlearis and soleus muscles and resulted from the additive effects of LPA and GLA. At 50 mg/kg, the metabolic improvements due to LPA-GLA were substantially reduced. In summary, these results indicate that the conjugate of the antioxidant LPA and the n-6 essential fatty acid GLA elicits significant dose-dependent improvements in whole body and skeletal muscle insulin action on glucose disposal in insulin-resistant obese Zucker rats. Moreover, these actions of LPA-GLA are due to the additive effects of its individual components.
Arterial baroreceptors control plasma vasopressin responses to graded hypotension in conscious dogs
Authors: Thrasher Terry N. , Chen Hong-Gen , Keil Lanny C.
Published: December 2017

We studied the role of cardiac and arterial baroreceptors in the reflex control of arginine vasopressin (AVP) and renin secretion during graded hypotension in conscious dogs. The dogs were prepared with Silastic cuffs on the thoracic inferior vena cava and catheters in the pericardial space. Each experiment consisted of a control period followed by four periods of inferior vena caval constriction, during which mean arterial pressure (MAP) was reduced in increments of ∼10 mmHg. The hormonal responses were measured in five dogs under four treatment conditions: 1) intact, 2) acute cardiac denervation (CD) by intrapericardial infusion of procaine, 3) after sinoaortic denervation (SAD), and 4) during combined SAD+CD. The individual slopes relating MAP to plasma AVP and plasma renin activity (PRA) were used to compare the treatment effects using a 2 × 2 factorial analysis. There was a significant ( P < 0.01) effect of SAD on the slope relating plasma AVP to MAP but no effect of CD and no SAD × CD interaction. In contrast, the slope relating PRA and MAP was increased ( P < 0.05) by SAD but was not affected by CD. These results support the hypothesis that stimulation of AVP secretion in response to graded hypotension is primarily driven by unloading arterial baroreceptors in the dog.
Metabolic control of food intake and estrous cycles in Syrian hamsters. I. Plasma insulin and leptin
Authors: Schneider Jill E. , Blum Robert M. , Wade George N.
Published: December 2017

The “adipostat hypothesis” refers to the idea that circulating hormone concentrations reflect levels of body adiposity and act as signals to control food intake and reproduction. Implicit in the adipostatic hypothesis are the following two assumptions: 1) plasma levels of adipostatic hormones accurately reflect body fat content and 2) decreased plasma concentrations of adipostatic hormones necessarily result in increased food intake and inhibited reproductive processes. The present experiments are designed to test these assumptions. Fat and lean Syrian hamsters were either fasted for 12, 24, 36, or 48 h or allowed ad libitum access to food. Contrary to the first assumption, plasma leptin and insulin levels in fat hamsters dropped dramatically by 12 h after the start of a fast, with no significant change in body fat content and no postfast hyperphagia. Lean hamsters showed anestrus after a 48-h fast but not after a 24-h fast. Contrary to the second assumption of the lipostatic hypothesis, lean hamsters fasted for 24 h and then refed for the next 24 h had leptin levels that were not significantly elevated compared with those of 48-h-fasted hamsters. Thus, in adult female Syrian hamsters, plasma leptin concentrations do not accurately reflect body fat content under all conditions; normal estrous cyclicity does not necessarily require plasma leptin concentrations higher than those of fasted hamsters; and decreased plasma leptin levels do not result in increased food intake.
Development of the pulmonary surfactant system in two oviparous vertebrates
Authors: Johnston Sonya D. , Orgeig Sandra , Lopatko Olga V. , Daniels Christopher B.
Published: December 2017

In birds and oviparous reptiles, hatching is often a lengthy and exhausting process, which commences with pipping followed by lung clearance and pulmonary ventilation. We examined the composition of pulmonary surfactant in the developing lungs of the chicken, Gallus gallus, and of the bearded dragon, Pogona vitticeps. Lung tissue was collected from chicken embryos at days 14, 16, 18 (prepipped), and 20(postpipped) of incubation and from 1 day and 3 wk posthatch and adult animals. In chickens, surfactant protein A mRNA was detected using Northern blot analysis in lung tissue at all stages sampled, appearing relatively earlier in development compared with placental mammals. Chickens were lavaged at days 16, 18, and 20 of incubation and 1 day posthatch, whereas bearded dragons were lavaged at day 55, days 57–60 (postpipped), and days 58–61 (posthatched). In both species, total phospholipid (PL) from the lavage increased throughout incubation. Disaturated PL (DSP) was not measurable before 16 days of incubation in the chick embryo nor before 55 days in bearded dragons. However, the percentage of DSP/PL increased markedly throughout late development in both species. Because cholesterol (Chol) remained unchanged, the Chol/PL and Chol/DSP ratios decreased in both species. Thus the Chol and PL components are differentially regulated. The lizard surfactant system develops and matures over a relatively shorter time than that of birds and mammals. This probably reflects the highly precocial nature of hatchling reptiles.
Tumor necrosis factor (TNF)-α induces leptin production through the p55 TNF receptor
Authors: Finck Brian N. , Johnson Rodney W.
Published: December 2017

Tumor necrosis factor (TNF)-α acts directly on adipocytes to increase production of the lipostatic factor, leptin. However, which TNF receptor (TNFR) mediates this response is not known. To answer this question, leptin was measured in plasma of wild-type (WT), p55, and p75 TNFR knockout (KO) mice injected intraperitoneally with murine TNF-α and in supernatants from cultured WT, p55, and p75 TNFR KO adipocytes incubated with TNF-α. Leptin also was measured in supernatants from C3H/HeOuJ mouse adipocytes cultured with blocking antibodies to each TNFR and TNF-α as well as in supernatants from adipocytes incubated with either human or murine TNF-α, which activate either one or both TNFR, respectively. The results using all four strategies show that the induction of leptin production by TNF-α requires activation of the p55 TNFR and that although activation of the p75 TNFR alone cannot cause leptin production, its presence affects the capability of TNF-α to induce leptin production through the p55 TNFR. These results provide new information on the interplay between cells of the immune system and adipocytes.
Effects of hypoxia, anoxia, and endogenous ethanol on thermoregulation in goldfish,Carassius auratus
Authors: Rausch Richard N. , Crawshaw Larry I. , Wallace Helen L.
Published: December 2017

Effects of hypoxia, anoxia, and endogenous ethanol (EtOH) on selected temperature (Tsel) and activity in goldfish were evaluated. Blood and brain EtOH concentrations ([EtOH]) and brain oxygen partial pressure ([Formula: see text]) were quantified at crucial ambient oxygen pressures. Below a threshold value near 31 Torr, Tseldecreased as a function of environmental[Formula: see text]. Tselof 15°C-acclimated fish was ∼10°C at the onset of anoxia and changed little over 2 h. Activity showed a similar response pattern. Brain [EtOH] was significantly elevated above control levels after 1 h anoxia. In normoxic water, Tselremained different in previously anoxic and normoxic control fish for ∼20 min. Blood [EtOH] of previously anoxic fish remained significantly elevated ([EtOH] >4.0 μmol/g blood), and activity was significantly depressed at 20 min. Brain[Formula: see text] reached normal levels in <3 min. We conclude that [EtOH] (brain or blood) and brain[Formula: see text] are not proximal causes of either behavioral anapyrexia (hypothermia) or inactivity in goldfish exposed to oxygen-depleted environments.
Isometric force and endurance in soleus muscle of thyroid hormone receptor-α1- or -β-deficient mice
Authors: Johansson Catarina , Lännergren Jan , Lunde Per-Kristian , Vennström Björn , Thorén Peter , Westerblad Håkan
Published: December 2017

The specific role of each subtype of thyroid hormone receptor (TR) on skeletal muscle function is unclear. We have therefore studied kinetics of isometric twitches and tetani as well as fatigue resistance in isolated soleus muscles of R-α1- or -β-deficient mice. The results show 20–40% longer contraction and relaxation times of twitches and tetani in soleus muscles from TR-α1-deficient mice compared with their wild-type controls. TR-β-deficient mice, which have high thyroid hormone levels, were less fatigue resistant than their wild-type controls, but contraction and relaxation times were not different. Western blot analyses showed a reduced concentration of the fast-type sarcoplasmic reticulum Ca2+-ATPase (SERCa1) in TR-α1-deficient mice, but no changes were observed in TR-β-deficient mice compared with their respective controls. We conclude that in skeletal muscle, both TR-α1 and TR-β are required to get a normal thyroid hormone response.
Prandial lactate infusion inhibits spontaneous feeding in rats
Authors: Silberbauer Christa J. , Surina-Baumgartner Denise M. , Arnold Myrtha , Langhans Wolfgang
Published: December 2017

To investigate the acute effects of lactate on spontaneous feeding, we infused lactate in the hepatic portal vein (0.5, 1.0, and 1.5 mmol lactate/meal) or in the vena cava (1.0 and 1.5 mmol lactate/meal) of ad libitum-fed rats during their first spontaneous nocturnal meal. Infusions (5 min, 0.1 ml/min) were remotely controlled, and a computerized feeding system recorded meal patterns. In separate crossover tests, meal size decreased independent of the infusion route after 1.0 and 1.5 mmol but not after 0.5 mmol lactate. The subsequent intermeal interval (IMI) tended to decrease only after vena cava infusion of 1.0 mmol lactate. The size of the second nocturnal meal increased after the 1.0 mmol lactate infusion. Hepatic portal infusion of 1.5 mmol lactate increased the satiety ratio [subsequent IMI (min)/meal size (g)] by 175%, which was higher than the insignificant 43% increase after vena cava infusion. Hepatic portal infusion of 1.5 mmol lactate also increased systemic plasma lactate but not glucose concentration at 1 min after the end of infusion. The results are consistent with the idea that meal-induced increases in circulating lactate play a role in the control of meal size (satiation). Moreover, the results suggest that lactate also contributes to postprandial satiety and that the liver is involved in this effect. The exact mechanisms of lactate's inhibitory effects on feeding and the site(s) where lactate acts to terminate meals remain to be identified.
Neonatal hypoxic hyperlipidemia in the rat: effects on aldosterone and corticosterone synthesis in vitro
Authors: Raff Hershel , Bruder Eric D. , Jankowski Barbara M. , Goodfriend Theodore L.
Published: December 2017

Neonatal hypoxia increases aldosterone production and plasma lipids. Because fatty acids can inhibit aldosterone synthesis, we hypothesized that increases in plasma lipids restrain aldosteronogenesis in the hypoxic neonate. We exposed rats to 7 days of hypoxia from birth to 7 days of age (suckling) or from 28 to 35 days of age (weaned at day 21). Plasma was analyzed for lipid content, and steroidogenesis was studied in dispersed whole adrenal glands untreated and treated to wash away lipids. Hypoxia increased plasma cholesterol, triglycerides, and nonesterified fatty acids in the suckling neonatal rat only. Washing away lipids increased aldosterone production in cells from 7-day-old rats exposed to hypoxia, but not in cells from normoxic 7-day-old rats or from normoxic or hypoxic 35-day-old rats. Addition of oleic or linolenic acid to washed cells inhibited both aldosterone and corticosterone production, although cells from hypoxic 7-day-old rats were less sensitive. We conclude that hypoxia induces hyperlipidemia in the suckling neonate and that elevated nonesterified fatty acids inhibit aldosteronogenesis.
Siberian hamsters that fail to reentrain to the photocycle have suppressed melatonin levels
Authors: Ruby Norman F. , Dubocovich Margarita L. , Heller H. Craig
Published: December 2017

Siberian hamsters readily reentrain to a 3-h phase delay of the photocycle (16 h light/day) but fail to reentrain to a 5-h phase delay. This study tested whether melatonin production was suppressed in animals that failed to reentrain. Melatonin was measured on the day before, day of, or several days after each phase shift. Melatonin levels measured 4 h after dark onset were ∼83 μg/ml on the day before each phase delay and undetectable (<6 μg/ml) during the light phase on the day of the phase shift. Activity onsets regained their prior phase relationship to the photocycle 4 (3 h) or 5 (5 h) days after the phase shift; on that day, melatonin levels were measured 4 h after dark onset. Melatonin levels were unaffected by the 3-h phase delay (>57.6 μg/ml) but were undetectable after a 5-h phase delay (<8 μg/ml). Thus melatonin remained suppressed only after the phase delay to which hamsters also fail to reentrain. This relationship suggests that the propensity for reentrainment may be influenced by changes in melatonin production following a phase shift of the photocycle.
Apoptosis in polycystic kidney disease: involvement of caspases
Authors: Ali Shujath M. , Wong Victoria Y. , Kikly Kristine , Fredrickson Todd A. , Keller Paul M. , DeWolf Walter E. , Lee Dennis , Brooks David P.
Published: December 2017

Polycystic kidney disease (PKD) is characterized by the development of large renal cysts and progressive loss of renal function. Although the cause of the development of renal cysts is unknown, recent evidence suggests that excessive apoptosis occurs in PKD. With the use of terminal deoxynucleotidyl transferase dUTP nick-end labeling staining, we have confirmed the presence of apoptotic bodies in cystic kidneys of congenital polycystic kidney (cpk) disease mice carrying a homozygous mutation at 3 wk of age. Apoptosis was localized primarily to the interstitium with little evidence of cell death in cyst epithelium or noncystic tubules. In addition, we observed that the expression of various caspases, bax and bcl-2, was upregulated in cystic kidneys. With the use of various substrates in enzyme activity assays, we have demonstrated a greater than sevenfold increase in caspase 4 activity and a sixfold increase in caspase 3 activity. These data suggest that there is a caspase-dependent apoptosis pathway associated with PKD and support the hypothesis that apoptotic cell death contributes to cyst formation in PKD.
Expression and localization of angiotensin subtype receptor proteins in the hypertensive rat heart
Authors: Ozono Ryoji , Matsumoto Toshiyuki , Shingu Tetsuji , Oshima Tetsuya , Teranishi Yasuhiro , Kambe Masayuki , Matsuura Hideo , Kajiyama Goro , Wang Zhi-Qin , Moore Allan F. , Carey Robert M.
Published: December 2017

The cellular localization of the AT2receptor and the regulation of its expression in hypertrophied left ventricle are not well known. We compared the expression of the cardiac AT1and AT2receptor in spontaneously hypertensive rats/Izumo strain (SHR/Izm) and Wistar Kyoto rats/Izumo strain (WKY/Izm), ages 4, 12, and 20 wk, by means of immunohistochemistry and Western blot analysis. In SHR/Izm, compared with WKY/Izm, blood pressure (161 ± 2 vs. 120 ± 2 mmHg at 12 wk, P ≤ 0.01, and 199 ± 3 vs. 123 ± 3 mmHg at 20 wk, P≤ 0.01) and heart-to-body weight ratio (3.76 ± 0.07 vs. 3.06 ± 0.06 mg/g at 12 wk, P ≤ 0.01, and 3.90 ± 0.08 vs. 3.01 ± 0.12 mg/g at 20 wk, P ≤ 0.01) were significantly elevated. There was no difference in these values between the two strains at 4 wk of age. Histologically, 20-wk-old SHR/Izm demonstrated myocardial hypertrophy, a thickening of the smooth muscle layer of the intracardiac arteries, and perivascular fibrosis. By immunohistochemistry, the AT2receptor was localized to cardiomyocytes and vascular endothelial cells, but not in the vascular smooth muscle cells. No major AT2receptor signal was observed in perivascular fibrosis at any age in either strain of rats. No difference was detected in this localization between the two strains. By Western blotting, a single 44-kDa band for the AT2receptor and a single 60-kDa band for the AT1receptor were detected in ventricles from both strains of rats at all ages. Densitometric analysis demonstrated that the AT2receptor 44-kDa band was decreased by 20% at 12 wk and 32% at 20 wk ( P < 0.01) in SHR/Izm compared with WKY/Izm. The intensity of the AT1receptor 60-kDa band was increased by 57% in 20-wk-old SHR/Izm compared with WKY/Izm ( P < 0.05). There was no significant difference in the intensity of the 44- or 60-kDa bands in 4-wk-old animals of either strain. We demonstrated a decrease in the AT2receptor and an increase in the AT1receptor protein with no change in their localizations in hypertrophied left ventricular myocytes of SHR/Izm.
Glucocorticoid-induced, caspase-dependent organ apoptosis early after burn injury
Authors: Fukuzuka Kunitaro , Edwards Carl K. , Clare-Salzler Michael , Copeland Edward M. , Moldawer Lyle L. , Mozingo David W.
Published: December 2017

Immune suppression and increased apoptotic loss of circulating lymphocytes have been reported after burn injury. However, little is known about the underlying mechanisms responsible for the increased apoptosis of lymphoid and parenchymal cells in solid organs and the role played by inflammatory mediators, such as tumor necrosis factor-α (TNF-α) and Fas ligand (FasL), as well as by glucocorticoids. To evaluate the role of endogenously produced glucocorticoids and FasL, mice subjected to a 20% steam burn were pretreated with a glucocorticoid receptor antagonist (mifepristone) or a neutralizing murine Fas fusion protein. Three and twenty-four hours after burn injury, histological analysis, caspase-3 activity, and in situ terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and phenotyping of lymphocyte populations for apoptosis were evaluated. Burn injury increased the number of apoptotic cells and caspase-3 activity in thymus and spleen, but not in other solid organs. Increased apoptosis was seen in several T and B cell populations from both thymus and spleen. Mifepristone pretreatment significantly reduced the apoptosis and caspase-3 activity after burn injury, whereas blocking FasL activity had only minimal effects. We conclude that corticosteroids, and not FasL, are primarily responsible for the increased caspase-3 activity and apoptosis in thymus and spleen cell populations early after burn injury.
Cardiac adrenomedullin gene expression and peptide accumulation after acute myocardial infarction in rats
Authors: Nagaya Noritoshi , Nishikimi Toshio , Yoshihara Fumiki , Horio Takeshi , Morimoto Atsushi , Kangawa Kenji
Published: December 2017

Plasma adrenomedullin (AM) has been shown to increase in the early phase of acute myocardial infarction (MI). However, little information is available regarding cardiac AM synthesis after MI. Accordingly, we examined the time course of ventricular AM production and potential stimulation of AM in the infarcted and noninfarcted regions in MI rats produced by coronary artery ligation. Compared with sham-operated rats, the ventricular AM peptide level 6 h after MI increased 1.5-fold in the infarcted region and 1.7-fold in the noninfarcted region in association with increased left ventricular end-diastolic pressure (EDP). Northern blot analysis also showed marked induction of AM gene expression in the infarcted region (11-fold) and the noninfarcted region (6-fold) 6 h after MI. The AM peptide level in the infarcted region reached its peak (2.6-fold) 1 wk postinfarction and thereafter decreased to normal. In the noninfarcted region, however, the AM level remained elevated for at least 4 wk. Immunohistochemical studies demonstrated that intense immunostaining for AM was limited to myocytes in both the infarcted and noninfarcted regions. Interestingly, the AM level in the noninfarcted region correlated positively with infarct size ( r = 0.40, P < 0.01) and EDP ( r = 0.52, P < 0.001). An oral angiotensin-converting enzyme inhibitor suppressed the overproduction of AM 1 wk postinfarction in association with decreases in EDP and mean arterial pressure. In summary, cardiac AM synthesis was rapidly induced in both the infarcted and noninfarcted regions after MI. The subsequent ventricular AM in the two regions demonstrated different time-concentration curves during 4 wk after MI. AM may be synthesized predominantly by cardiac myocytes, but not by fibroblasts, at least in part, in association with increased ventricular load after MI.
Systemic injection of a nitric oxide synthase inhibitor suppresses sleep responses to sleep deprivation in rats
Authors: Ribeiro Ana Cristina , Gilligan John G. , Kapás Levente
Published: December 2017

We hypothesized that nitric oxide (NO) may play a role in homeostatic sleep regulation. To test this hypothesis, we studied the sleep deprivation (SD)-induced homeostatic sleep responses after intraperitoneal administration of an NO synthase inhibitor, Nω-nitro-l-arginine methyl ester (l-NAME, a cumulative dose of 100 mg/kg). Amounts and intensity of sleep were increased in response to 8 h of SD in control rats ( n = 8). Sleep amounts remained above baseline for 16 h after SD followed by a negative rebound. Rapid eye movement sleep (REMS) and non-REMS (NREMS) intensities were elevated for 16 and 4 h, respectively. l-NAME treatment ( n = 8) suppressed the rebound increases in NREMS amount and intensity. REMS rebound was attenuated by l-NAME in the first dark period after SD; however, a second rebound appeared in the subsequent dark period. REMS intensity did not increase after SD in l-NAME-injected rats. The finding that the NO synthase inhibitor suppressed rebound increases in NREMS suggests that NO may play a role as a signaling molecule in homeostatic regulation of NREMS.
Circulating levels of glucagon-like peptide-2 in human subjects with inflammatory bowel disease
Authors: Xiao Qiang , Boushey Robin P. , Cino Maria , Drucker Daniel J. , Brubaker Patricia L.
Published: December 2017

Glucagon-like peptide-2 (GLP-2) is a recently characterized intestine-derived peptide that exerts trophic activity in the small and large intestine. Whether circulating levels of GLP-2 are perturbed in the setting of human inflammatory bowel disease (IBD) remains unknown. The circulating levels of bioactive GLP-2-(1—33) compared with its degradation product GLP-2-(3—33) were assessed using a combination of RIA and HPLC in normal and immunocompromised control human subjects and patients hospitalized for IBD. The activity of the enzyme dipeptidyl peptidase IV (DP IV), a key determinant of GLP-2-(1—33) degradation was also assessed in the plasma of normal controls and subjects with IBD. The circulating levels of bioactive GLP-2-(1—33) were increased in patients with either ulcerative colitis (UC) or Crohn's Disease (CD; to 229 ± 65 and 317 ± 89%, P < 0.05, of normal, respectively). Furthermore, the proportion of total immunoreactivity represented by intact GLP-2-(1—33), compared with GLP-2-(3—33), was increased from 43 ± 3% in normal healthy controls to 61 ± 6% ( P < 0.01) and 59 ± 2% ( P < 0.01) in patients with UC and CD, respectively. The relative activity of plasma DP IV was significantly reduced in subjects with IBD compared with normal subjects (1.4 ± 0.3 vs. 5.0 ± 1.1 mU/ml, respectively; P< 0.05). These results suggest that patients with active IBD may undergo an adaptive response to intestinal injury by increasing the circulating levels of bioactive GLP-2-(1—33), facilitating enhanced repair of the intestinal mucosal epithelium in vivo.
Metallothionein is expressed in adipocytes of brown fat and is induced by catecholamines and zinc
Authors: Beattie John H. , Wood Anne M. , Trayhurn Paul , Jasani Bharat , Vincent Adele , McCormack Graeme , West Adrian K.
Published: December 2017

Metallothionein (MT) is thought to have an antioxidant function and is strongly expressed during activation of thermogenesis and increased oxidative stress in brown adipose tissue (BAT). Localization and regulation of MT expression in BAT was therefore investigated in rats and mice. Immunohistochemical analysis of BAT from rats exposed to 4°C for 24 h showed that MT and uncoupling protein 1 (UCP1) were coexpressed in differentiated adipocytes, and both cytoplasmic and nuclear localization of MT was observed. Cold induction of MT-1 expression in BAT was also observed in mice. Administration of norepinephrine to rats and isoproterenol to mice stimulated MT and UCP1 expression in BAT, implying a sympathetically mediated pathway for MT induction. In mice, zinc, and particularly dexamethasone, induced MT-2 expression in BAT and liver. Surprisingly, zinc also induced UCP1 in BAT, suggesting that elevated zinc may induce thermogenesis. We conclude that expression of MT in mature brown adipocytes upon β-adrenoceptor activation is consistent with a role in protecting against physiological oxidative stress or in facilitating the mobilization or utilization of energy reserves.
Single-fiber myosin heavy chain polymorphism during postnatal development: modulation by hypothyroidism
Authors: di Maso Nick A. , Caiozzo Vincent J. , Baldwin Kenneth M.
Published: December 2017

The primary objective of this study was to follow the developmental time course of myosin heavy chain (MHC) isoform transitions in single fibers of the rodent plantaris muscle. Hypothyroidism was used in conjunction with single-fiber analyses to better describe a possible linkage between the neonatal and fast type IIB MHC isoforms during development. In contrast to the general concept that developmental MHC isoform transitions give rise to muscle fibers that express only a single MHC isoform, the single-fiber analyses revealed a very high degree of MHC polymorphism throughout postnatal development. In the adult state, MHC polymorphism was so pervasive that the rodent plantaris muscles contained ∼12–15 different pools of fibers (i.e., fiber types). The degree of polymorphism observed at the single-fiber level made it difficult to determine specific developmental schemes analogous to those observed previously for the rodent soleus muscle. However, hypothyroidism was useful in that it confirmed a possible link between the developmental regulation of the neonatal and fast type IIB MHC isoforms.
Exercise-induced translocation of Na+-K+pump subunits to the plasma membrane in human skeletal muscle
Authors: Juel Carsten , Nielsen Jens Jung , Bangsbo Jens
Published: December 2017

Six human subjects performed one-legged knee extensor exercise (90 ± 4 W) until fatigue (exercise time 4.6 ± 0.8 min). Needle biopsies were obtained from vastus lateralis muscle before and immediately after exercise. Production of giant sarcolemmal vesicles from the biopsy material was used as a membrane purification procedure, and Na+-K+pump α- and β-subunits were quantified by Western blotting. Exercise significantly increased ( P < 0.05) the vesicular membrane content of the α2-, total α-, and β1-subunits by 70 ± 29, 35 ± 10, and 26 ± 5%, respectively. The membrane content of α1was not changed by exercise, and the densities of subunits in muscle homogenates were unchanged. The ratio of vesicular to crude muscle homogenate content of the α2-, total α-, and β1-subunits was elevated during exercise by 67 ± 33 ( P < 0.05), 23 ± 6 ( P < 0.05), and 40 ± 14% ( P = 0.06), respectively. It is concluded that translocation of subunits is an important mechanism involved in the short time upregulation of the Na+-K+pumps in association with human muscle activity.
Elevation of tail skin temperature in ovariectomized rats in relation to menopausal hot flushes
Authors: Kobayashi Tsunefumi , Tamura Mizuho , Hayashi Minoru , Katsuura Yasuhiro , Tanabe Hirofumi , Ohta Tomohiro , Komoriya Keiji
Published: December 2017

Menopausal hot flushes (HFs), which manifest as an increase in skin temperature, most frequently occur after menopause and cease with the passage of time. We designed this study to elucidate the characteristics of the elevation of tail skin temperature (TST) in ovariectomized (OVX) rats, which is relevant to human symptoms of HFs. First, we measured TST and rectal temperature (RT) and investigated the time course of their changes up to 20 wk after ovariectomy. The TST in OVX rats (28.4 ± 0.3°C) was significantly ( P = 0.0035) elevated from 2 to 7 wk after the ovariectomy compared with that in sham-operated (Sham) rats (27.0 ± 0.2°C), whereas the RT in OVX rats was elevated from 8 to 20 wk. We next examined the therapeutic effects of estradiol (E2) on the elevation of the TST by continuous subcutaneous infusion. E2 treatment (1.0 μg/day) completely ( P = 0.0232) inhibited the elevation of the TST (28.4 ± 0.3°C for Sham rats, 29.3 ± 0.3°C for OVX rats, 28.2 ± 0.4°C for OVX + E2 1.0 μg/day rats). These results demonstrated that the elevation of TST in OVX rats was exhibited soon after the estrogen removal and diminished with time and that it was normalized with continuous E2 replacement. These characteristics are similar to the symptoms of menopausal HFs in women.
Role of endotoxin in the expression of endothelial selectins after cecal ligation and perforation
Authors: Bauer Philippe , Lush Cameron W. , Kvietys Peter R. , Russell Janice M. , Granger D. Neil
Published: December 2017

The objectives of this study were to determine 1) the changes in endothelial cell adhesion molecule expression that occur in a clinically relevant model of sepsis and 2) the dependence of these changes on endotoxin [lipopolysaccharide (LPS)]. The dual radiolabeled monoclonal antibody technique was used to quantify the expression of E- and P-selectin in LPS-sensitive (C3HeB/FeJ) and LPS-insensitive (C3H/HeJ) mice that were subjected to acute peritonitis by cecal ligation and perforation (CLP). At 6 h after CLP, the expression of both E- and P-selectin was increased in the gut (mesentery, pancreas, and small and large bowel) compared with the sham-operated and/or control animals, with a more marked response noted in LPS-insensitive mice. The lung also exhibited an increased P-selectin expression in both mouse strains. An accumulation of granulocytes, assessed using tissue myeloperoxidase activity, was noted in the lung and intestine of LPS-sensitive but not LPS-insensitive mice exposed to CLP. These results indicate that the CLP model of sepsis is associated with an upregulation of endothelial selectins in the gut vasculature and that enteric LPS does not contribute to this endothelial cell activation response.
Range of entrainment of rat circadian rhythms to sinusoidal light-intensity cycles
Authors: Usui Setsuo , Takahashi Yasuro , Okazaki Terue
Published: December 2017

The range of entrainment of the circadian behavioral rhythm was compared between two groups of Sprague-Dawley rats (each n = 10) exposed to daily cycles of rectangular light-dark alternation (LD) and sinusoidal fluctuations of light intensity (SINE), respectively. The maximum illuminance (20 lx), the minimum illuminance (0.01 lx), and the total amount of light exposure per cycle were the same under the two lighting conditions. The periods (Ts) of both lighting cycles were lengthened stepwise from 24 through 25, 26, 26.5, 27, 27.5, and 28 h to 28.5 h in experiment 1 and were shortened stepwise from 24 through 23.5, 23, and 22.5 h to 22 h in experiment 2. Each T cycle lasted for 30 cycles. In experiment 1, 60% of rats under the LD condition entrained up to T = 28.5 h, whereas 50% of rats under the SINE condition entrained up to T = 28.5 h. In experiment 2, no animal under the LD condition entrained to T < 23.5 h, whereas 40% of rats under the SINE condition entrained down to T = 23 h and 20% of rats remained to entrain down to T = 22 h cycles. The phase angle of entrainment was systematically changed, depending on T under both conditions. These results suggest that the lower limit of entrainment is expanded under the SINE condition compared with the LD condition.
Hepatic glucokinase is induced by dietary carbohydrates in rainbow trout, gilthead seabream, and common carp
Authors: Panserat S. , Médale F. , Blin C. , Brèque J. , Vachot C. , Plagnes-Juan E. , Gomes E. , Krishnamoorthy R. , Kaushik S.
Published: December 2017

Glucokinase (GK) plays a central role in glucose homeostasis in mammals. The absence of an inducible GK has been suggested to explain the poor utilization of dietary carbohydrates in rainbow trout. In this context, we analyzed GK expression in three fish species (rainbow trout , gilthead seabream, and common carp) known to differ in regard to their dietary carbohydrate tolerance. Fish were fed for 10 wk with either a diet containing a high level of digestible starch (>20%) or a diet totally deprived of starch. Our data demonstrate an induction of GK gene expression and GK activity by dietary carbohydrates in all three species. These studies strongly suggest that low dietary carbohydrate utilization in rainbow trout is not due to the absence of inducible hepatic GK as previously suggested. Interestingly, we also observed a significantly lower GK expression in common carp (a glucose-tolerant fish) than in rainbow trout and gilthead seabream, which are generally considered as glucose intolerant. These data suggest that other biochemical mechanisms are implicated in the inability of rainbow trout and gilthead seabream to control blood glucose closely.
Differential inducible nitric oxide synthase expression in systemic and pulmonary vessels after endotoxin
Authors: Pulido Edward J. , Shames Brian D. , Fullerton David A. , Sheridan Brett C. , Selzman Craig H. , Gamboni-Robertson Fabia , Bensard Denis D. , McIntyre Robert C.
Published: December 2017

Inducible nitric oxide synthase (iNOS) is associated with vascular hypocontractility in systemic vessels after endotoxin lipopolysaccharide (LPS) administration. Although lung iNOS is increased after LPS, its role in the pulmonary circulation is unclear. We hypothesized that whereas iNOS upregulation is responsible for LPS-induced vascular dysfunction in systemic vessels, iNOS does not play a significant role in the pulmonary artery (PA). Using isolated aorta (AO) and PA rings, we examined the effect of nonselective NOS inhibition [ NG-monomethyl-l-arginine (l-NMMA); 100 μmol/l] and selective iNOS inhibition (aminoguanidine, AG; 100 μmol/l) on α1-adrenergic-mediated vasoconstriction (phenylephrine; 10−9to 10−3M) after LPS ( Salmonella typhimurium, 20 mg/kg ip). We also determined the presence of iNOS using Western blot and immunohistochemistry. LPS markedly impaired AO contractility (maximal control tension 1,076 ± 33 mg vs. LPS 412 ± 39 mg, P < 0.05), but PA contractility was unchanged (control 466 ± 29 mg vs. LPS 455 ± 27 mg, P > 0.05). Selective iNOS inhibition restored the AO's response to vasoconstriction (LPS + AG 1,135 ± 54 mg, P > 0.05 vs. control and P < 0.05 vs. LPS), but had no effect on the PA (LPS + AG 422 ± 38 mg, P > 0.05 vs. control and LPS). Western blot and immunohistochemistry revealed increased iNOS expression in the AO after LPS, but iNOS was not detected in the PA. Our results suggest that differential iNOS expression after LPS in systemic and pulmonary vessels contributes to the phenomenon of sepsis/endotoxemia-induced systemic hypotension and pulmonary hypertension.
Evidence that platelet-derived growth factor may be a novel endogenous pyrogen in the central nervous system
Authors: Pelá Irene R. , Ferreira Márcia E. S. , Melo Miriam C. C. , Silva Carlos A. A. , Coelho Márcio M. , Valenzuela C. Fernando
Published: December 2017

Platelet-derived growth factor (PDGF) exerts neurotrophic and neuromodulatory actions in the mammalian central nervous system (CNS). Like the cytokines, PDGF primarily signals through tyrosine phosphorylation-dependent pathways that activate multiple intracellular molecules including Janus family kinases. We previously showed that microinjection of PDGF-BB into the lateral ventricle induced a febrile response in rats that was reduced by pretreatment with Win 41662, a potent inhibitor of PDGF receptors (Pelá IR, Ferreira MES, Melo MCC, Silva CAA, and Valenzuela CF. Ann NY Acad Sci 856: 289–293, 1998). In this study, we further characterized the role of PDGF-BB in the febrile response in rats. Microinjection of PDGF-BB into the third ventricle produced a dose-dependent increase in colonic temperature that peaked 3–4 h postinjection. Win 41662 attenuated fever induced by intraperitoneal injection of bacterial lipopolysaccharide, suggesting that endogenous PDGF participates in the febrile response to this exogenous pyrogen. Importantly, febrile responses induced by tumor necrosis factor-α, interleukin-1β, and interleukin-6 were unchanged by Win 41662. Both indomethacin and dexamethasone blocked the PDGF-BB-induced increase in colonic temperature, and, therefore, we postulate that PDGF-BB may act via prostaglandin- and/or inducible enzyme-dependent pathways. Thus our findings suggest that PDGF-BB is an endogenous CNS mediator of the febrile response in rats.
Maturational differences between vascular and bladder smooth muscle during ovine development
Authors: Arens Yvonne H. J. M. , Rosenfeld Charles R. , Kamm Kristine E.
Published: December 2017

Maturation rates of vascular and visceral smooth muscle (SM) during ovine development were compared by quantifying contractile protein, myosin heavy chain (MHC) isoform contents, and contractile properties of aortas and bladders from female fetal ( n = 19) and postnatal ( n = 21) sheep. Actin, myosin, and protein contents rose progressively throughout development in both tissues ( P ≤ 0.003); however, expression patterns differed. During the last trimester, i.e., 101–130 days (term ∼145 days), bladder actin and MHC contents were approximately twofold greater ( P < 0.04) than those in the aorta. Although the fractional content of 204-kDa SM1 MHC in the bladder decreased from 74 ± 3% at midgestation to 48 ± 2% 3 mo postnatal, the aorta exhibited an increase from 30 ± 2% to 65 ± 2%. Bladder MHC (MHC-B) migrating at 200 kDa contained only SM2 throughout development. In contrast, 200-kDa MHC in the aorta was predominantly nonmuscle MHC-B at midgestation, which was gradually replaced by SM2 as development progressed. Along with its early expression of SM2, bladder muscle obtained maximal stress generating capacity (1.7 × 105N/m2) by term gestation, whereas the aorta exhibited no contractions until after birth. We conclude that whereas aortic SM maturation is delayed until after birth, bladder SM matures biochemically and functionally during prenatal development, thus supporting early requirements for micturition.
Enterostatin suppresses food intake in rats after near-celiac and intracarotid arterial injection
Authors: Lin Ling , Bray George , York David A.
Published: December 2017

Enterostatin (Ent) selectively suppresses the intake of dietary fat after peripheral and central administration. To further investigate the site of action of Ent, we compared the feeding responses to Ent injected intra-arterially near the celiac artery, into the carotid artery, or intravenously in rats adapted to a high-fat diet. After near-celiac arterial injection there was an immediate dose-dependent (0.05–13.5 nmol) inhibition of food intake occurring within 5 min in overnight-fasted rats that lasted up to 20 min. Carotid arterial Ent had a similar, immediate dose-related response, and the inhibitory effect was long lasting. The response to intravenous Ent was only evident at the highest dose (13.5 nmol) and was delayed for at least 120 min. Pretreatment with capsaicin, which causes degeneration of vagal sensory neurons, abolished the inhibitory responses to near-celiac Ent but not to intravenous or intracarotid Ent. These results provide further evidence for both a gastrointestinal site of action for peripheral Ent and a central site of action for intracarotid Ent and suggest that the delayed response to intravenous Ent may reflect either binding or slow uptake of this peptide into the central nervous system.
MRF-4 exhibits fiber type- and muscle-specific pattern of expression in postnatal rat muscle
Authors: Walters E. H. , Stickland N. C. , Loughna P. T.
Published: December 2017

The crucial role played by the myogenic regulatory factors (MRFs) in the development of skeletal muscle has been well characterized. The continued expression of these factors in skeletal muscle of the postnatal animal has led to the suggestion that they may play a role in the regulation of muscle fiber phenotype. The few studies that have examined the expression of MRF-4 in postnatal muscle have been carried out at the whole muscle level. These studies demonstrated that this factor is expressed at a higher level than any other MRF but suggested that this was not affected by muscle phenotype. In this study, the expression of the MRF-4 transcript has been examined at the cellular level by in situ hybridization. It was observed that in the mixed fiber type muscle the gastrocnemius, MRF-4 was preferentially expressed in slow muscle fibers, but in the slow postural soleus, no fiber type specificity was observed. These observations suggest that MRF-4 may play a role in the regulation of muscle fiber phenotype in the postnatal animal.
Antipyretic effect of arginine vasotocin in toads
Authors: Bicego-Nahas K. C. , Steiner A. A. , Carnio E. C. , Antunes-Rodrigues J. , Branco L. G. S.
Published: December 2017

Arginine vasotocin (AVT) is a nonmammalian analog of the mammalian hormone arginine vasopressin (AVP). These peptides are known for their antidiuretic and pressor effects. More recently, AVP has been recognized as an important antipyretic molecule in mammals. However, no information exists about the role of AVT in febrile ectotherms. We tested the hypothesis that AVT is an antipyretic molecule in the toad Bufo paracnemis. Toads equipped with a temperature probe were placed in a thermal gradient, and preferred body temperature was recorded continuously. A behavioral fever was observed after lipopolysaccharide (LPS) was injected systemically (200 μg/kg). Systemically injected AVT (300 pmol/kg) alone caused no significant change in body temperature, but abolished LPS-induced fever. Moreover, a smaller dose of AVT (10 pmol/kg), which did not affect LPS-induced fever when injected peripherally, abolished fever when injected intracerebroventricularly. We therefore conclude that AVT plays an antipyretic role in the central nervous system, by means of behavior, in an ectotherm, a fact consistent with the notion that AVT/AVP elicits antipyresis by reducing the thermoregulatory set point.
Increased central AT1-receptor activation, not systemic vasopressin, sustains hypertension in ANP knockout mice
Authors: Ackermann Uwe , Azizi Newsha
Published: December 2017

We tested the hypothesis that hypertension in atrial natriuretic peptide (ANP) knockout mice is caused in part by disinhibition of angiotensin II-mediated vasopressin release. Inactin-anesthetized F2 homozygous ANP gene-disrupted mice (−/−) and wild-type (+/+) littermates were surgically prepared for carotid arterial blood pressure measurement (ABP) and background intravenous injection of physiological saline or vasopressin V1-receptor antagonist (Manning compound, 10 ng/g body wt) and subsequent intracerebroventricular (left lateral ventricle) injection of saline (5 μl) or ANP (0.5 μg) or angiotensin II AT1-receptor antagonist losartan (10 μg). Only (−/−) showed significant decrease in ABP after intracerebroventricular ANP or losartan. Both showed significant hypotension after intravenous V1 antagonist, but there was no difference between their responses. We conclude that 1) vasopressin contributes equally to ABP maintenance in ANP-disrupted mice and wild-type controls; 2) permanently elevated ABP in ANP knockouts is associated with increased central nervous angiotensin II AT1-receptor activation; 3) disinhibition of central nervous angiotensin II AT1receptors in ANP-deficient animals does not lead to a significant increase in the importance of vasopressin as a mechanism for blood pressure maintenance.