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1.
This study examined the postprandial metabolism and swimming speed of southern bluefin tuna Thunnus maccoyii when fed sardines Sardinops sagax of either high‐lipid and high‐energy content or low‐lipid and low‐energy content. Five groups of two or three T. maccoyii (mean ±s.e. mass = 19·8 ± 0·5 kg, n = 14) were fed either low [2·2% lipid, 5·5 MJ kg?1 gross energy (GE)] or high‐lipid (12·9%, 9·2 MJ kg?1 GE) S. sagax. Before feeding, T. maccoyii swam at 0·74 ± 0·03 body lengths s?1 (n = 5) and their routine metabolic rate was 305 ± 15 mg kg?1 h?1. Swimming speed and metabolic rate of T. maccoyii increased following feeding. Thunnus maccoyii swam 1·3 and 1·8 times faster during digestion of low and high‐lipid S. sagax, respectively. Postprandial peak metabolic rate, duration of elevated metabolism and total postprandial metabolic increment were all greater for T. maccoyii that ingested high‐lipid S. sagax. When total postprandial increment is represented as a proportion of ingested energy, there was no difference between high and low‐lipid meals, equating to between 30 and 35% of ingested energy. It was estimated that increased postprandial swimming costs account for 25 and 46% of the total postprandial metabolic response for low and high‐lipid S. sagax meals, respectively. Specific dynamic action (SDA) accounts for c. 20% of ingested energy regardless of S. sagax lipid level. These results confirm that the postprandial metabolic increment of T. maccoyii is greater than most other fish species. Much of the high cost of postprandial metabolic increment can be attributed to increased postprandial swimming costs. For T. maccoyii, it appears that activity and SDA are not independent, which complicates bioenergetic evaluation. High postprandial metabolic costs accentuate the great energetic requirements of T. maccoyii.  相似文献   

2.
This study was carried out to investigate the effects of chromium intake on glycemic control, markers of cardio-metabolic risk, and oxidative stress in infertile polycystic ovary syndrome (PCOS) women candidate for in vitro fertilization (IVF). This randomized double-blind, placebo-controlled trial was done among 40 subjects with infertile PCOS candidate for IVF, aged 18–40 years old. Individuals were randomly allocated into two groups to take either 200 μg/day of chromium (n?=?20) or placebo (n?=?20) for 8 weeks. Biochemical parameters were assessed at baseline and at end-of-trial. Compared with the placebo, taking chromium supplements led to significant reductions in fasting plasma glucose (??2.3?±?5.7 vs. +?0.9?±?3.1 mg/dL, P?=?0.03), insulin levels (??1.4?±?2.1 vs. +?0.4?±?1.7 μIU/mL, P?=?0.004), homeostatic model of assessment for insulin resistance (??0.3?±?0.5 vs. +?0.1?±?0.4, P?=?0.005), and a significant increase in quantitative insulin sensitivity check index (+?0.004?±?0.008 vs. ??0.001?±?0.008, P?=?0.03). In addition, chromium supplementation significantly decreased serum triglycerides (??19.2?±?33.8 vs. +?8.3?±?21.7 mg/dL, P?=?0.004), VLDL- (??3.8?±?6.8 vs. +?1.7?±?4.3 mg/dL, P?=?0.004) and total cholesterol concentrations (??15.3?±?26.2 vs. ??0.6?±?15.9 mg/dL, P?=?0.03) compared with the placebo. Additionally, taking chromium supplements was associated with a significant increase in plasma total antioxidant capacity (+?153.9?±?46.1 vs. ??7.8?±?43.9 mmol/L, P?<?0.001) and a significant reduction in malondialdehyde values (?0.3?±?0.3 vs. +?0.1?±?0.2 μmol/L, P?=?0.001) compared with the placebo. Overall, our study supported that chromium administration for 8 weeks to infertile PCOS women candidate for IVF had beneficial impacts on glycemic control, few variables of cardio-metabolic risk, and oxidative stress.  相似文献   

3.
Excessive ingestion of mercury—a health hazard associated with consuming predatory fishes—damages neurological, sensory-motor and cardiovascular functioning. The mercury levels found in Bigeye Tuna (Thunnus obesus) and bluefin tuna species (Thunnus maccoyii, Thunnus orientalis, and Thunnus thynnus), exceed or approach levels permissible by Canada, the European Union, Japan, the US, and the World Health Organization. We used DNA barcodes to identify tuna sushi samples analysed for mercury and demonstrate that the ability to identify cryptic samples in the market place allows regulatory agencies to more accurately measure the risk faced by fish consumers and enact policies that better safeguard their health.  相似文献   

4.
In order to evaluate the phylogenetic relationships and taxonomic classification of the Iranian endemic Tanacetum paradoxum Bornm. (Asteraceae, Anthemideae), a molecular analysis based on nrDNA ITS sequences of 16 species of Tanacetum together with representatives of 27 genera of subtribes Artemisiinae and Handeliinae as well as a micromorphological study of achenes and pollen grains was performed. The chromosome number of 2n?=?2x?=?16 and the genome size of T. paradoxum (2C?=?8.81?±?0.19?pg) are reported here for the first time. Due to the well-supported close phylogenetic relationship of T.?paradoxum to the species of the genus Artemisia (Bayesian inference, posterior probability PP?=?1), which is supported by cytological (x?=?8) and micromorphological features concerning the achene shape and pollen type, the combination Artemisia paradoxa (Bornm.) Sonboli is proposed.  相似文献   

5.
Impacts of abiotic factors on low lying salt marsh species have been closely evaluated as unique stressors, but few studies have determined the physiological and morphological responses to predicted climate change conditions. This study investigated the effects of water state (tidal, flooded and drought) and salinity on Triglochin buchenaui K?cke, Mering and Kadereit, newly separated from the Triglochin bulbosa L. complex. Growth, proline concentration, relative water content, electrolyte leakage, chlorophyll concentration and morphological analyses were done following 3?months of treatments. Results showed significant variation in height (7.57?±?0.5?C29?±?1.55?cm, p?<?0.005, df?=?55), leaf area increments and relative growth rates which decreased with increasing salinity under all water states. There was almost a cessation of growth under submergence which reduces the plant??s regeneration potential under these conditions. Proline accumulation (1.84?±?0.23?C3.36?±?0.38?mg?g?1 DW), response of photosynthetic pigments and electrolyte leakage (8.17?±?0.80?C38.36?±?7.42?%???S?g?1?FW) were fundamental to osmotic and membrane response regulation. Plants survived in all water states at salinity up to 45?ppt, but the optimum range was 0?C18?ppt, and best water state was the tidal condition. Viable rhizomes were produced under drought conditions but in the absence of seed banks, regeneration of the species following prolonged submergence may not be possible due to absence of both rhizomes and seeds. In their natural habitat, highly succulent T. buchenaui plants (29?±?1.55?cm tall and above) are indicative of freshwater conditions.  相似文献   

6.
Bats in hot roosts experience some of the most thermally challenging environments of any endotherms, but little is known about how heat tolerance and evaporative cooling capacity vary among species. We investigated thermoregulation in three sympatric species (Nycteris thebaica, Taphozous mauritianus and Sauromys petrophilus) in a hot, semi-arid environment by measuring body temperature (T b), metabolic rate and evaporative water loss (EWL) at air temperatures (T a) of 10?C42?°C. S. petrophilus was highly heterothermic with no clear thermoneutral zone, and exhibited rapid increases in EWL at high T a to a maximum of 23.7?±?7.4?mg?g?1?h?1 at T a????42?°C, with a concomitant maximum T b of 43.7?±?1.0?°C. T. mauritianus remained largely normothermic at T as below thermoneutrality and increased EWL to 14.7?±?1.3?mg?g?1?h?1 at T a????42?°C, with a maximum T b of 42.9?±?1.6?°C. In N. thebaica, EWL began increasing at lower T a than in either of the other species and reached a maximum of 18.6?±?2.1?mg?g?1?h?1 at T a?=?39.4?°C, with comparatively high maximum T b values of 45.0?±?0.9?°C. Under the conditions of our study, N. thebaica was considerably less heat tolerant than the other two species. Among seven species of bats for which data on T b as well as roost temperatures in comparison to outside T a are available, we found limited evidence for a correlation between overall heat tolerance and the extent to which roosts are buffered from high T a.  相似文献   

7.
A new diploid (2n?=?30) species, Rhaponticoides calabrica, is described from Calabria and Basilicata (southern Italy). This species differs from the closely related R. centaurium – an endemic of Apulia and northern Basilicata – by different flower colour (white in the former, purplish in the latter), width of membranous margin of phyllaries (1.8?±?0.4 mm vs 0.8?±?0.3 mm) and pappus length (6.8?±?0.9 mm vs 9.1?±?1.0 mm). The two species are completely allopatric and seem to have also different chromosome numbers.  相似文献   

8.
Ribosomal RNA genes have been widely used for the identification and phylogenetic analysis of various organisms, including parasitic protozoa. Here, we report nine near full-length Theileria orientalis 18S rRNA gene sequences from cattle from different areas of Myanmar. Phylogenetic analysis of the 18S rRNA genes revealed a considerably close genetic relationship among T. orientalis isolates from Australia, China, Japan, Korea, Myanmar, and Pakistan. We also obtained four Theileria velifera-like (Theileria cf. velifera) 18S rRNA gene sequences from two cattle and two water buffaloes from the northernmost area of Myanmar. The phylogenetic analysis of T. cf. velifera isolates from Myanmar along with T. velifera and T. cf. velifera isolates from African countries suggested an evolutionary lineage of greater complexity in T. velifera-related parasites. DNA alignment analysis indicated the presence of 51 and 55 nucleotide variation positions within the 18S rRNA genes from 15 T. orientalis and 11 T. velifera-related isolates, respectively. Alignment entropy analysis of the 18S rRNA sequences indicated that both T. orientalis and T. velifera-related isolates had three hyper variable regions, corresponding to V2, V4, and V7 regions in eukaryotes. The degree of variation was prominent in the V2 in T. orientalis and V4 in T. velifera-related isolates. The secondary structure analysis of the 18S rRNA predicted using minimum free energy algorism revealed that the structure of V4 region differed most significantly between T. orientalis and T. velifera. These results provide novel insights into common structures, variations and functions of small subunit rRNA in Theileria species.  相似文献   

9.

Background

Riociguat is a soluble guanylate cyclase stimulator approved for pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTPEH). The objective of this study was to evaluate right heart size and function assessed by echocardiography during long term treatment with riociguat.

Methods

Patients who started riociguat treatment (1.0–2.5?mg tid) within the trials phase II, PATENT, PATENTplus, EAS, CHEST and continued treatment for 3–12?months were included in this study. Echocardiography was analysed off-line at baseline, after 3, 6 and 12?months by investigators who were blinded to clinical data. Last and baseline observation carried forward method (LOCF, BOCF) were performed as sensitivity analysis.

Results

Seventy-one patients (45% PAH, 55% CTEPH; 53.5% female; 60?±?13?years, mean pulmonary arterial pressure 46?±?10?mmHg, mean PVR 700?±?282dynes·sec·cm-5) were included. After 6?months, RA and RV area, RV thickness tricuspid regurgitation velocity showed a significant reduction. After 12?months, patients receiving riociguat therapy showed a significant reduction in right atrial (??2.6?±?4.4?cm2, 95% CI -3.84, ??1.33; p?<?0.001, n?=?49) and right ventricular (RV) area (??3.5?±?5.2?cm2, 95% CI -5.1, ??1.9; p?<?0.001; n?=?44), RV thickness (??0.76?±?2.2?mm, 95% CI -1.55, 0.03; n?=?32), and a significant increase in TAPSE (2.95?±?4.78?mm, 95% CI 1.52, 4.39; n?=?45) and RV fractional area change (8.12?±?8.87?mm, 95% CI 4.61, 11.62; n?=?27).Both LOCF and BOCF showed similar results but lower effect sizes.

Conclusion

Patients under long-term treatment with riociguat show significantly reduced right heart size and improved RV function in PAH and CTEPH. Further controlled prospective studies are needed to confirm these results.
  相似文献   

10.
The host behavioral and immune (encapsulation) defenses against the parasitoid Anagyrus sp. nr. pseudococci were compared for five mealybug species with different phylogenetic relationships and geographical origins: i) a Mediterranean native mealybug species, Planococcus ficus, with a long co-evolutionary history with the parasitoid; ii) three alien mealybugs species, Planococcus citri, Pseudococcus calceolariae and Pseudococcus viburni, with a more recent co-evolutionary history; and iii) a fourth alien mealybug species, Phenacoccus peruvianus, with no previous common history with the parasitoid. Three host defense behaviors were registered: abdominal flipping, reflex bleeding and walking away. The native host Pl. ficus and its congener Pl. citri exhibited the lowest probability of defense behavior (0.11?±?0.01 and 0.09?±?0.01 respectively), whereas the highest value was observed in P. viburni (0.31?±?0.02). Intermediate levels of defense behavior were registered for Ps. calceolariae, and Ph. peruvianus. The probability of parasitoid encapsulation was lowest and highest for two alien host species, Ph. peruvianus (0.20?±?0.07) and Ps. viburni (0.86?±?0.05), respectively. The native host Pl. ficus, its congener Pl. citri and Ps. calceolariae showed intermediate values (0.43?±?0.07, 0.52?±?0.06, and 0.45?±?0.09, respectively). The results are relevant with respect to biological control and to understand possible evolutionary processes involved in host range of A. sp. nr. pseudococci.  相似文献   

11.
Three calcareous intercalations within lignite sequences in the open-cast mine Belchatów (51°15’N, 19°20’E) yield rich land snail faunas of over 40 species. Fission-track ages of these faunas (Be?-A and Bel-B) range from 18.1 ± 1.7 Ma to 16.5 ± 1.3 Ma, though the Be?-C level lies below the dated tuffitic intercalations and seems to be older. Five species of Cyclophoridae and Pomatiasidae are described including two new species:Procydotella?glazeki n. sp. andCaspicyclotus belchatoviensis n. sp.  相似文献   

12.
The carbohydrate-binding sequences (CBS) in the lectin genes of Trifolium repens, T. pratense, and T. trichocephalum were sequenced. The gene regions encoding lectin CBS of T. pratense and T. repens displayed a considerable similarity; however, the CBS of these species differed essentially. Moreover, T. repens formed a compact cluster with Melilotus albus and M. officinalis in the phylogenetic trees constructed according to the nucleotide sequences and the corresponding CBS of legume lectins. T. trichocephalum does not fall into the group of the tribe Trifolieae members according to both the amino acid sequence of lectin carbohydrate-binding region and the nucleotide sequence of lectin gene.  相似文献   

13.
In order to infer phylogenetic relationships between tuna species of the genus Thunnus, partial sequences of the mitochondrial cytochrome b and ATPase genes were determined in all eight species. Supplemental restriction analysis on the nuclear rRNA gene was also carried out. Pacific northern bluefin tuna (Thunnus thynnus orientalis) was found to have mtDNA distinct from that of the Atlantic subspecies (T. t. thynnus) but very similar to that from the species albacore (T. alaluga). In contrast, no differentiation in nuclear genome was observed between the Atlantic and Pacific northern bluefin tunas. The Atlantic northern bluefin and southern bluefin tunas possessed mtDNA sequences very similar to species of yellowfin tuna group and not so similar to albacore and bigeye tunas which were morphologically assigned to the bluefin tuna group. The molecular data indicate that (1) mtDNA from albacore has been incorporated into the Pacific population of northern bluefin tuna and has extensively displaced the original mtDNA, and (2) albacore is the earliest offshoot, followed by bigeye tuna in this genus, which is inconsistent with the phylogenetic relationships between these tuna species inferred from morphology. Correspondence to: S. Chow  相似文献   

14.
Contents of 52 trace elements in intact prostate of 64 apparently healthy 13?C60-year-old men (mean age 36.5?years) were investigated by inductively coupled plasma mass spectrometry. Mean values (M ± S????) for mass fraction (in milligrams per kilogram, on dry-weight basis) of trace elements were as follows: Ag 0.041?±?0.005, Al 36?±?4, Au 0.0039?±?0.0007, B 0.97?±?0.13, Be 0.00099?±?0.00006, Bi 0.021?±?0.008, Br 29?±?3, Cd 0.78?±?0.09, Ce 0.028?±?0.004, Co 0.035?±?0.003, Cs 0.034?±?0.003, Dy 0.0031?±?0.0005, Er 0.0018?±?0.0004, Gd 0.0030?±?0.0005, Hg 0.046?±?0.006, Ho 0.00056?±?0.00008, La 0.074?±?0.015, Li 0.040?±?0.004, Mn 1.53?±?0.09, Mo 0.30?±?0.03, Nb 0.0051?±?0.0009, Nd 0.013?±?0.002, Ni 4.3?±?0.7, Pb 1.8?±?0.4, Pr 0.0033?±?0.0004, Rb 15.9?±?0.6, Sb 0.040?±?0.005, Se 0.73?±?0.03, Sm 0.0027?±?0.0004, Sn 0.25?±?0.05, Tb 0.00043?±?0.00009, Th 0.0024?±?0.0005, Tl 0.0014?±?0.0001, Tm 0.00030?±?0.00006, U 0.0049?±?0.0014, Y 0.019?±?0.003, Yb 0.0015?±?0.0002, Zn 782?±?97, and Zr 0.044?±?0.009, respectively. The upper limit of mean contents of As, Cr, Eu, Ga, Hf, Ir, Lu, Pd, Pt, Re, Ta, and Ti were the following: As ??0.018, Cr ??0.64, Eu ??0.0006, Ga ??0.08, Hf ??0.02, Ir ??0.0004, Lu ??0.00028, Pd ??0.007, Pt ??0.0009, Re ??0.0015, Ta ??0.005, and Ti ??2.6. In all prostate samples, the content of Te was under detection limit (<0.003). Additionally, ratios of the Zn content to other trace element contents as well as correlations between Zn and trace elements were calculated. Our data indicate that the human prostate accumulates such trace elements as Al, Au, B, Br, Cd, Cr, Ga, Li, Mn, Ni, Pb, U, and Zn. No special relationship between Zn and other trace elements was found.  相似文献   

15.
Cytochrome c (Cyt c) was rapidly oxidized by molecular oxygen in the presence, but not absence of PEG. The redox potential of heme c was determined by the potentiometric titration to be +236?±?3?mV in the absence of PEG, which was negatively shifted to +200?±?4?mV in the presence of PEG. The underlying the rapid oxidation was explored by examining the structural changes in Cyt c in the presence of PEG using UV–visible absorption, circular dichroism, resonance Raman, and fluorescence spectroscopies. These spectroscopic analyses suggested that heme oxidation was induced by a modest tertiary structural change accompanied by a slight shift in the heme position (<1.0?Å) rather than by partial denaturation, as is observed in the presence of cardiolipin. The near-infrared spectra showed that PEG induced dehydration from Cyt c, which triggered heme displacement. The primary dehydration site was estimated to be around surface-exposed hydrophobic residues near the heme center: Ile81 and Val83. These findings and our previous studies, which showed that hydrated water molecules around Ile81 and Val83 are expelled when Cyt c forms a complex with CcO, proposed that dehydration of these residues is functionally significant to electron transfer from Cyt c to CcO.  相似文献   

16.
Growth models describe the change in length or weight as a function of age. Growth curves in tunas can take different forms from relatively simple von Bertalanffy growth curves (Atlantic bluefin, albacore tunas) to more complex two- or three-stanza growth curves (yellowfin, bigeye, skipjack, southern bluefin tunas). We reviewed the growth of the principal market tunas (albacore, bigeye, skipjack, yellowfin and the three bluefin tuna species) in all oceans to ascertain the different growth rates among tuna species and their implications for population productivity and resilience. Tunas are among the fastest-growing of all fishes. Compared to other species, tunas exhibit rapid growth (i.e., relatively high K) and achieve large body sizes (i.e., high L ). A comparison of their growth functions reveals that tunas have evolved different growth strategies. Tunas attain asymptotic sizes (L ), ranging from 75 cm FL (skipjack tuna) to 400 cm FL (Atlantic bluefin tuna), and reach L at different rates (K), varying from 0.95 year?1 (skipjack tuna) to 0.05 year?1 (Atlantic bluefin tuna). Skipjack tuna (followed by yellowfin tuna) is considered the “fastest growing” species of all tunas. Growth characteristics have important implications for population dynamics and fisheries management outcomes since tunas, and other fish species, with faster growth rates generally support higher estimates of Maximum Sustainable Yield (MSY) than species with slower growth rates.  相似文献   

17.
Theileria sinensis was recently isolated and named as an independent Theileria species that infects cattle in China. To date, this parasite has been described based on its morphology, transmission and molecular studies, indicating that it should be classified as a distinct species. To test the validity of this taxon, the two internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene were cloned and sequenced from three T. sinensis isolates. The complete ITS sequences were compared with those of other Theileria sp. available in GenBank. Phylogenetic analyses based on sequence data for the complete ITS sequences indicate that T. sinensis lies in a distinct clade that is separate from that of T. buffeli/orientalis and T. annulata. Sequence comparisons indicate that different T. sinensis isolates possess unique sizes of ITS1 and ITS2 as well as species-specific nucleotide sequences. This analysis provides new molecular data to support the classification of T. sinensis as a distinct species from other known Theileria spp. based on ITS sequences.  相似文献   

18.
This study describes the feeding ecology of three pelagic shark species in the California Current: shortfin mako (Isurus oxyrinchus); blue (Prionace glauca); and thresher (Alopias vulpinus) sharks. Stomach contents of sharks collected from 2002 to 2008 were identified to the lowest taxonomic level and analyzed using univariate and multivariate methods. Of 330 mako sharks sampled (53 to 248?cm fork length [FL]), 238 stomachs contained 42 prey taxa, with jumbo squid (Dosidicus gigas) and Pacific saury (Cololabis saira) representing the most important prey based on the geometric index of importance (GII). In addition, 158 blue sharks were sampled (76 to 248?cm FL) and 114 stomachs contained 38 prey taxa, with jumbo and Gonatus spp. squids representing the most important prey. Lastly, 225 thresher sharks were sampled (108 to 228?cm FL) and 157 stomachs contained 18 prey taxa with northern anchovy (Engraulis mordax) and Pacific sardine (Sardinops sagax) identified as the most important prey. Overall, mako sharks had the most diverse diet based upon Simpson??s diversity index (1/D) (8.43?±?1.16), feeding on many species of teleosts and cephalopods, followed by blue sharks (6.20?±?2.11) which consumed a wide range of prey (primarily cephalopods), while thresher sharks were most specialized (2.62?±?0.34), feeding primarily on coastal pelagic teleosts. Dietary overlap was lowest between blue and thresher sharks (S?rensen similarity index?=?0.321 and Simplified Morisita Horn index?=?0.006), and seasonal variability in diet was greatest for blue sharks (Simplified Morisita Horn index?=?0.260, Analysis of Similarity (ANOSIM) p?<?0.001). In addition, size class, and subregion were significant factors that affected diet of each species differently (ANOSIM p?<?0.001). Despite similarities in life history characteristics and spatial and temporal overlap in habitat, diets of these three common shark species are distinct in the California Current.  相似文献   

19.
In the present study we have evaluated the effect of a single hemodialysis session on the brain-derived neurotrophic factor levels in plasma [BDNF]pl and in serum [BDNF]s as well as on the plasma isoprostanes concentration [F2 isoprostanes]pl, plasma total antioxidant capacity (TAC) and plasma cortisol levels in chronic kidney disease patients. Twenty male patients (age 69.8?±?2.9?years (mean?±?SE)) with end-stage renal disease undergoing maintenance hemodialysis on regular dialysis treatment for 15?C71?months participated in this study. A single hemodialysis session, lasting 4.2?±?0.1?h, resulted in a decrease (P?=?0.014) in [BDNF]s by ~42?% (2,574?±?322 vs. 1,492?±?327?pg?ml?1). This was accompanied by an increase (P?<?10?4) of [F2-Isoprostanes]pl (38?±?3 vs. 116?±?16?pg?ml?1), decrease (P?<?10?4) in TAC (1,483?±?41 vs. 983?±?35 trolox equivalents, ??mol?l?1) and a decrease (P?=?0.004) in plasma cortisol level (449.5?±?101.2 vs. 315.3?±?196.3?nmol?l?1). No changes (P?>?0.05) in [BDNF]pl and the platelets count were observed after a single dialysis session. Furthermore, basal [BDNF]s in the chronic kidney disease patients was significantly lower (P?=?0.03) when compared to the age-matched control group (n?=?23). We have concluded that the observed decrease in serum BDNF level after hemodialysis accompanied by elevated [F2-Isoprostanes]pl and decreased plasma TAC might be caused by enhanced oxidative stress induced by hemodialysis.  相似文献   

20.
Activation of the dopamine (DA) D2 receptor inhibits glucose-stimulated insulin secretion in isolated rodent islets in vitro; however, no information is available regarding the cellular localization of DA receptors (DRs, including D1-D5 receptors) in pancreatic islets in situ. We investigate the protein expression and cellular localization of five types of DRs in pancreatic islets by means of Western blotting and double-labeling immunofluorescence in both normal control and alloxan-induced type 1 diabetes model (T1DM) rats. In control rats, D1 immunoreactivity (-IR) was distributed in the core of the islet and co-localized with insulin-IR, D2-IR was peripherally distributed and found only in somatostatin-immunoreactive cells and D5-IR was co-localized with glucagon-IR and pancreatic polypeptide-IR. No IR for either the D3 or D4 receptor was observed in rat islets. The protein level of the D1 receptor was reduced in T1DM rats (D1/D-glyceraldehyde-3-phosphate dehydrogenase [GAPDH], 0.63?±?0.05 in control rats compared with 0.16?±?0.03 in T1DM rats, n?=?8, P?n?=?8, P?=?0.42) or the D5 receptor (D5/GAPDH, 0.50?±?0.04 compared with 0.47?±?0.04, n?=?8, P?=?0.58). The present study is the first clear demonstration of the protein expression and cellular localization of the D1, D2 and D5 receptors in rat pancreatic islets and provides crucial morphological evidence for further investigations of the underlying mechanism regarding the DA regulation of pancreatic endocrine function.  相似文献   

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