Dietary intake effects on arginine vasotocin and aldosterone in cloacal fluid of whitebellied sunbirds (Nectarinia talatala)

The main objective of this study was to determine whether or not the renal outputs of the osmoregulatory hormones arginine vasotocin (AVT) and aldosterone (ALDO) reflect the osmotic status of whitebellied sunbirds (Nectarinia talatala). The birds were fed a range of sucrose concentrations (from 0.07 to 2.5 mol/l, with osmolalities of 70 to approximately 5,800 mosM/kg), and adjusted their intakes so that they drank large volumes of dilute diets and small volumes of concentrated diets. Renal fluid outputs were appropriately regulated so that large volumes of cloacal fluid (CF) were voided on the dilute diets and small volumes on the concentrated diets. Accordingly, plasma AVT concentrations increased with increasing sugar concentration; however, AVT outputs in CF did not change in a similar manner, rather they decreased as dietary concentration increased. It was not possible to measure plasma ALDO concentrations in the small sunbirds because of insufficient blood samples available; however, ALDO outputs in CF did vary with the sucrose diets and renal function, being highest on the most concentrated diet. In addition ALDO output in CF fell markedly when sodium was added to the 0.5 mol/l sucrose diet. We conclude that in sunbirds fed increasingly concentrated sucrose solutions, changes in CF outputs of ALDO, but not AVT, appear to reflect the water flux and hydration state of these birds.     

The involvement of arginine vasotocin in the maturation of the kitten brain

In order to investigate the effects of the nonapeptide hormone arginine vasotocin (AVT) on the maturation of the brain, the following developmental data were tabulated between 5 and 21 days of postnatal life, in kittens, after the daily intraperitoneal administration of 10^?6 mg synthetic AVT: sleep, daily increase of body weight and locomotor, and investigative activities (LIA). Likewise, the day of the eye opening was noted and the brain weight as well as the total lipid levels within the brain in the day of sacrifice (21 days of age) were measured. The daily administration of AVT induced: (1) an increase of the total amount as well as of the intensity of active sleep (AS); (2) a decrease of the LIA; (3) a decrease of the total lipid levels within the brain and (4) a retardation of the eye opening. These effects appeared to be specific because neither arginine vasopressin, nor oxytocin, in the same doses (10^?6 mg), were able to reproduce the effects of AVT. The present results demonstrate that chronic administration of AVT is associated with a retardation of brain maturation. Whether AVT induces this effect by an unique mechanism or there are different mechanisms for the reported developmental data that were affected by AVT, is unknown. However, the present results suggest that the pineal gland, by its effector within the brain, AVT, is involved by an inhibitory pathway in the brain maturation and the hypothesis is advanced that the decrease of AVT content of fetal and neonatal brain could represent a hormonal signal for triggering the beginning of the brain maturation phenomena.     

The effects of arginine vasotocin and catecholamines on nitrogen excretion and the cardio-respiratory physiology of the gulf toadfish, Opsanus beta

Simultaneous measurements of cardio-respiratory variables, oxygen uptake and whole body urea/ammonia/tritiated water effluxes were performed on cannulated gulf toadfish, Opsanus beta, before and after intra-arterial injection of the vasoactive agents, adrenaline, isoproterenol and arginine vasotocin. These experiments were conducted to test the hypothesis that the phenomenon of pulsatile urea excretion might reflect sudden changes in the general diffusive properties of the gill for solute transfer. Injection of isoproterenol (final nominal circulating level = 10⁻⁶ mol l⁻¹), was used as a tool to maximise the diffusive and perfusive conditions for branchial solute transfer. This protocol caused a pronounced reduction in arterial blood pressure, an elevation of cardiac frequency and associated increases in whole body urea and tritiated water effluxes; ammonia excretion and oxygen uptake were unaffected. Injection of adrenaline (final nominal circulating level=10⁻⁶ mol l⁻¹), caused a significant increase in arterial blood pressure and a tachycardia, yet nitrogen excretion and oxygen uptake were unaffected. Injection of arginine vasotocin, caused a dose-dependent (final nominal circulating levels = 10⁻¹¹–10⁻⁹ mol l⁻¹) increase in arterial blood pressure without affecting cardiac or ventilation frequency. At the two higher concentrations, arginine vasotocin caused large and transient increases in urea excretion without significantly affecting ammonia, water or oxygen fluxes. These results suggest that increased gill diffusive or perfusive conductance, while capable of augmenting urea efflux, cannot fully explain the sudden and massive increases in urea transfer associated with pulsatile urea excretion in toadfish. It is suggested that pulsatile urea excretion in this species may reflect a specific enhancement of urea excretion under the control of the neurohypophyseal hormone, arginine vasotocin. Accepted: 21 April 1998     

慢性肾衰竭患者肠道菌群改变与肾小球滤过率的关系

探究慢性肾衰竭患者肠道菌群结构改变与肾小球滤过率的关系。

选取2017年3月至2020年3月我院收治的202例慢性肾衰竭患者作为试验组, 并选取198例同期健康体检者作为对照组。收集两组入选者粪便标本并进行检测, 对比两组入选者肠道菌群数量; 同时对比两组入选者体质量、肾小球滤过率、血肌酐、血尿素氮、血胱抑素C水平, 采用Pearson相关性分析肠道菌群改变与肾小球滤过率的相关性。

相比于对照组, 试验组患者肠道双歧杆菌(t=21.915, P < 0.001)、大肠埃希菌数量显著降低(t=18.220, P < 0.001), 肠球菌数量显著增高(t=16.782, P < 0.001)。相比于对照组, 试验组患者肾小球滤过率(t=147.035, P < 0.001)显著降低, 血肌酐(t=43.129, P < 0.001)、血尿素氮(t=170.206, P < 0.001)、血胱抑素C(t=22.432, P < 0.001)水平显著增高。Spearman相关性分析显示, 慢性肾衰竭患者肠道双歧杆菌(r=-0.695, P < 0.001)和大肠埃希菌(r=-0.631, P < 0.001)与肾小球滤过率呈负相关。Logistic回归分析显示, 双歧杆菌、大肠埃希菌、肠球菌、血肌酐、血尿素氮和血胱氨酸均是慢性肾衰竭患者肾小球滤过率降低的独立危险因素。

慢性肾衰竭患者肠道双歧杆菌和大肠埃希菌数量降低、肠球菌数量升高, 且与肾小球滤过率呈显著负相关。

     

Apolipoprotein E gene polymorphism,hypercholesterolemia and glomerular filtration rate in type 2 diabetic subjects: A 9-year follow-up study

OBJECTIVE: To study the association between apolipoprotein E (apoE) genotype and the rate of decline in glomerular filtration rate (GFR) in type 2 diabetic patients in a 9-year prospective study. METHODS: GFR was determined in 84 type 2 diabetic patients by plasma clearance of (51)Cr-EDTA at baseline and after 9 years of follow-up. ApoE genotypes were determined by polymerase chain reaction and restriction enzyme HHAI digestion and designated as epsilon4 allele group (apoE4/2, 4/3 and 4/4 genotypes; n = 20) and non-epsilon4 allele group (apoE3/3 and E3/2 genotypes; n = 64). We focused our analysis on those patients who were more likely to progress to diabetic renal disease, i.e. whose GFR fell more than expected in the normal course of ageing [1 ml x min(-1) x (1.73 m(2))(-1) per year]. RESULTS: In the whole population, the decline in the GFR did not differ statistically significantly between the apoE genotype groups [p = 0.65 with analysis of variance for repeated variables (RANOVA) for interaction between apoE genotype group and time point]. However, among patients whose GFR changed more than 9 ml x min(-1) x (1.73 m(2))(-1), GFR showed a statistically significantly greater decline in the epsilon4 allele group (n = 11) than in the non-epsilon4 allele group (n = 43) [from 116 +/- 36 to 80 +/- 29 ml x min(-1) x (1.73 m(2))(-1) vs. from 119 +/- 20 to 96 +/- 18 ml x min(-1) x (1.73 m(2))(-1); p = 0.005 with RANOVA]. CONCLUSION: ApoE allele epsilon4 may speed up the rate of decline of the GFR in patients with progressive diabetic renal disease.     

Plasma levels of arginine vasotocin,prolactin, aldosterone and corticosterone during prolonged dehydration in the domestic flowl: effect of dietary NaCl

Three groups of White Plymouth Rock laying hens were adapted to three levels of dietary NaCl: low-NaCl food with tap water (LOW), high-NaCl food (1% NaCl w/w added) with tap water (HT), and high-NaCl food with 0.5% NaCl for drinking (HS). The birds were subjected to water deprivation (dehydration) for 18 days. Blood sampling was done at 2-4 day intervals. Plasma concentrations of arginine vasotocin (AVT), prolactin (PRL), aldosterone (ALDO) and corticosterone (CS) were determined by radioimmunoassay. Plasma osmolality, sodium, chloride, and potassium were also determined. In the normally hydrated hens fully adapted to the diets, there was a stepwise increase from LOW to HS in plasma osmolality (305, 315, 332 mOsm, for LOW, HT and HS, respectively), [Na+] (144, 153, 161 mM) and [Cl-] (109, 119, 127 mM) as well as in [AVT] (6, 14, 18 pg/ml) and [PRL] (16, 24, 34 ng/ml). Regressing [AVT] on osmolality gave a slope of 0.30 pg . ml-1/mOsm and a threshold of 273 mOsm. The slope of [PRL] on osmolality was 0.73 ng . ml-1/mOsm. The correlation coefficient of [AVT] and [PRL] was 0.67. LOW had high [ALDO] (165 pg/ml) which was suppressed to low levels in HT and HS (5-8 pg/ml), while [CS] was the same in all groups (0.9-1.1 ng/ml). Plasma [K+] was decreased in the high-NaCl groups (5.8 mM in LOW, 4.4 and 4.7 mM in HT and HS). Dehydration resulted within 2 days generally in a sharp (5-15%) increase in osmolality, [Na+] and [Cl-], which thereafter increased more slowly during the remaining 16 days in all groups, with the slowest increase in LOW. The levels of osmolality [Na+] and [Cl-] were 5% lower in LOW than in HT and HS, which showed the same levels during the dehydration period. Plasma [AVT] and [PRL] increased 2-4 fold within 2 days of dehydration; [AVT] reached a plateau at 29 pg/ml in all groups, but [PRL] continued to rise in all groups, fastest in LOW, reaching similar levels in all groups after 14-18 days of dehydration, about 85 ng/ml. The correlation coefficient of [AVT] and [PRL] was decreased by half (to 0.32) during dehydration. Plasma [ALDO] increased in all groups with dehydration, 1.7 fold in LOW and 3-6 fold in HT and HS, but the levels reached in HT and HS were only 15-30% of that seen in LOW.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effects of arginine vasotocin (AVT) on the behavioral, cardiovascular, and corticosterone responses of starlings (Sturnus vulgaris) to crowding

Previous studies in European starlings have concluded that conspecific crowding can be a significant stressor that is capable of simultaneously altering behavior, heart rate, and corticosterone (CORT) concentrations. It was hypothesized that the peptide hormone arginine vasotocin (AVT) has a role in the regulation of these three types of responses to crowding. Four male and four female resident starlings were submitted to nine combinations of 3 crowding treatments (0, 1, or 5 intruder starlings) and 3 subcutaneous injections (1, 4 microg AVT, and saline control). Resident starlings were given a treatment injection, their heart rate and behavior were monitored for 30 min, 0, 1, or 5 intruder Starlings were allowed to enter the residents cage, and HR and behavior were monitored for another 30 min. Blood samples were taken before and after all treatments to assess CORT concentrations. Exogenous AVT decreased the frequency of maintenance behaviors (feeding, drinking, preening, and beak wiping), as well as activity in resident starlings. Although aggressive behaviors upright posture, head feather expansion, and pecking) increased during crowding, these increases were significantly attenuated by AVT. Heart rate was significantly lower during these behavioral effects, and the CORT data indicate that the cardiovascular and behavioral effects are not dependent on significant increases in CORT. These data support the hypothesis that AVT's attenuation of general behavior and crowding induced aggression are modulated by a cardiovascular mechanism.     

Plasma concentrations of arginine vasotocin, prolactin, aldosterone and corticosterone in relation to oviposition and dietary NaCl in the domestic fowl

The osmolality and concentrations of Na, K, Cl and the hormones arginine vasotocin (AVT), prolactin, aldosterone and corticosterone were measured in plasma as functions of time in relation to oviposition, changing NaCl content of the diet, and feeding-inanition. AVT was significantly increased immediately after oviposition (but not during the hour before) with a calculated average value of 38.0 +/- 4.1 pg/ml at oviposition. A moderate increase in concentrations of prolactin and corticosterone were observed immediately after oviposition. Oviposition was not associated with detectable changes in plasma osmolality (and electrolyte concentrations) nor with the concentration of aldosterone. After a sudden change from a high NaCl diet to a low NaCl diet the plasma osmolality and concentrations of NaCl, AVT and prolactin reached new stable levels in 24 hr, whereas the plasma aldosterone concentration required more than 4 days to reach a steady level. After resalination plasma aldosterone was suppressed in less than 8 hr. Both osmolality and concentrations of AVT and prolactin showed transient overshoots during the first 24 hr. NaCl depletion resulted in a transient increase of corticosterone.     

Renal function and plasma arginine vasotocin during water deprivation in an Australian parrot,the galah (Cacatua roseicapilla)

Summary Renal function was measured in an Australian parrot, the galah (Cacatua roseicapilla), which is distributed across the most arid regions of the continent. Renal function was assessed by the constant infusion technique in hydrated galahs, and in both hydrated and dehydrated birds by means of osmotic minipumps. The glomerular filtration rate (GFR) of the galah is similar to calculated values for a bird of its size. However, effective renal plasma flow tended to be low and therefore filtration fraction was high. Water deprivation for a period of 5 days caused a decrease in body weight and an increase in plasma osmolality and haematocrit. The GFR declined steadily such that weight-specific GFR on the fifth day of water deprivation was 68% of control values. The water deprivation produced a 2.6-fold elevation of plasma arginine vasotocin (AVT) levels, with an overall sensitivity of release of AVT of 0.16±0.02 pg·ml^-1 per mOsm·kg^-1. The galah possesses renal mechanisms which enable it to conserve significant amounts of water during times of water stress.Abbreviations AVT arginine vasotocin - EDTA ethylene diamine tetra-acetate - GFR glomerular filtration rate - P _AVT plasma arginine vasotocin - PAH para-amino hippuric acid - SNGFR single nephron glomerular filtration rate     

Effect of estrogen and its antagonist on the expression of arginine vasotocin (AVT) and its oxytocic-like receptor VT3 in the shell gland of Japanese quail, Coturnix coturnix japonica

Avian neurohypophysial hormone arginine vasotocin (AVT) is known to regulate shell gland contractility during oviposition. While studying the role of estrogen in the expression and regulation of AVT and its oxytocic-like receptor VT3, using in situ hybridization and immunohistochemistry, it was observed that the expression of AVT and its receptor was not detected in the shell gland of sexually immature Japanese quail. However, administration of estrogen to these birds not only stimulates the growth and activity (as assessed by increased mucosal fold length, total protein content and alkaline phosphatase level) of the shell gland but also upregulates the expression of AVT and VT3. Further, administration of estrogen antagonist tamoxifen to sexually mature bird shows opposite results. On the other hand, localization of ir-AVT, observed in the ovary of sexually mature bird, was not detected in the estrogen treated sexually immature quail. It is concluded that estrogen not only affects the growth and differentiation of avian oviduct, but also regulates the expression of shell gland AVT and its receptor VT3. Present findings suggest that the locally synthesized AVT acts in a paracrine way to upregulate VT3 receptor and thus facilitates the endocrine function of neurohypophysial AVT during oviposition.     

The effect of intravenous hypertonic saline infusion on renal function and vasopressin excretion in sheep.

Conscious Merino ewes were given an intravenous hypertonic sodium chloride load of 4 mmol.min-1 for 100 min. This resulted in increases in urine flow, sodium and potassium excretion and plasma sodium concentration and osmolality. Urinary vasopressin output and solute-free water reabsorption increased and plasma renin activity declined. Renal plasma flow and glomerular filtration rate (GFR) rose, as did the solute clearance. The change in urinary osmolality was related to the initial urine osmolality such that when the initial urine osmolality was high the urine became more dilute, and vice versa. Tubular sodium reabsorption increased but the fractional reabsorption rate fell. It is suggested that the increase in GFR was at least partly due to the increase in AVP and that the electrolyte loss can be accounted for by the increase in GFR without necessarily involving AVP or other hormonal effects at the tubular level.     

Regulation of body temperature,metabolic rate,and sleep in fasting pigeons diurnally infused with glucose or saline

Summary To test the hypothesis that nocturnal body temperature (T_b) and metabolic rate (MR) in the pigeon are regulated during sleep at levels proportional to energy reserves, continuous recordings of T_b, oxygen consumption ( O₂), carbon dioxide production, and electrophysiological measures were taken from five pigeons subjected to two separate 4-day fasts. Energy reserves were depleted differentially during the fasts by 12-h diurnal infusions of either saline or isosmotic glucose solutions. Although T_b and O₂ were closely correlated, O₂ declined throughout the fast during diurnal and nocturnal phases of the 12:12 light-dark cycle whereas significant declines in T_b were restricted to the night. Diurnal thermal conductance declined over days of fasting, especially during saline infusions, and was reduced to minimal levels each night. The durations and distributions of arousal states did not change during the fast or differ between conditions. The results were consistent with the hypothesis of a nocturnal regulation of T_b and metabolic rate proportional to energy reserves.Abbreviations C ₁ thermal conductance - EEG electroencephalogram - EMG electromyogram - EOG electrooculogram - LD light-dark - MHP metabolic heat production - MR metabolic rate - REM rapid eye movement sleep - RQ respiratory quotient - SWS slow wave sleep - T _a ambient temperature - T _b body temperature - TRT total recording time - TST total sleep time - O₂ oxygen consumption     

Impact of glomerular filtration rate on urinary BNP and NT-proBNP levels in heart failure

B-type natriuretic peptide (BNP) and its inactive amino-terminal fragment (NT-proBNP) are diagnostic tools for heart failure (HF), but less is understood regarding the effects of renal function on their urinary concentrations. The objective was to analyze the influence of renal function, as estimated glomerular filtration rate (eGFR), on BNP and NT-proBNP concentrations in 90 HF outpatients (65 ± 12 years; 73% men), grouped according to eGFR below or above 60 mL/min. Patients with worse eGFR had higher serum NT-proBNP (p < 0.01) and BNP (p < 0.01) than patients with higher eGFR: NT-proBNP, but urinary levels did not reach statistical differences. In addition, a direct significant correlation between filtered load of serum NT-proBNP or BNP with their concentrations in urine was found in patients with eGFR above 60 mL/min (r = 0.66, p < 0.001 and r = 0.338, p < 0.05) and below 60 mL/min (r = 0.63, p < 0.001 and r = 0.406, p < 0.01). However, after normalizing urinary natriuretic peptide concentrations by their filtered load, we obtained a significant inverse and exponential relation in patients with worse renal function for NT-proBNP and BNP (r = -0.87, p = 0.001; and r = -0.71, p < 0.001, respectively) and in patients with eGFR>60 mL/min (r = -0.84, p < 0.001; and r = -0.72, p < 0.001, respectively). In conclusion, similar urinary NT-proBNP and BNP excretion was obtained in patients with high or low eGFR. Furthermore, despite the direct correlation between filtered load of serum natriuretic peptides with their urinary levels, an inverse an exponential relationship was obtained after normalizing urinary concentrations. Therefore, glomerular filtration does not seem to be the major determinant of both urinary peptide concentrations.     

Correlation of gastric mucosal damage with sialic acid profile in rats: effect of hydrochloric acid, pepsin and hypertonic saline

Sialic acids occupy terminal positions on gastric mucus glycoprotein where they contribute to the high viscosity of mucin. Desialylation of mucus may lead to degradation of the mucus and eventually to the breakdown of the gastric mucus barrier. The effect of a variety of damaging agents (0.1 M HCl, 2 mg ml(-1) pepsin and 2 M NaCl) on sialic acid profile was determined in pylorus-ligated rats. The relationship between sialic acid, galactose, pyruvate and the extent of gastric mucosal damage were studied. Instillation of pepsin significantly increased total sialic acid, galactose and macroscopic mucosal lesions in the stomach. Instillation of 0.1 M HCl reduced the total sialic acid but this decrease was not significant. Acidity led to a significant increase in the amount of free sialic acid in the gastric instillates and the macroscopic lesions induced by acid was not significantly different from the control animals (0.15 M NaCl). 2 M NaCl induced the macroscopic lesions in the stomach and also free sialic acid in the instillates. Pepsin potentiates the action of 2 M NaCl. In all the agents examined with the exception of acid, it was observed that an increase in free sialic acid and galactose was accompanied by gastric mucosal erosion and elevation of pyruvate concentration. It is concluded that gastric acidity alone is not inherently damaging and that resistance of gastric mucosa to destructive agents may be dependent on the integrity of the sialic acids.     

Use of a serum-based glomerular filtration rate prediction equation to assess renal function by age, sex, fasting, and health status in bottlenose dolphins (Tursiops truncatus)

Glomerular filtration rate (GFR) is a direct measurement of renal function. Although clearance tests using 24‐h urine collection or blood sample series are gold standards for measuring GFR, serum‐based prediction of GFR based upon the Modification of Diet in Renal Disease (MDRD) Study equation is acceptable for routine use in human adults. The purpose of our study was to assess the ability for a modified MDRD Study equation to predict expected changes in GFR in bottlenose dolphins (Tursiops truncatus) using a healthy dolphin population represented by 1,103 routine serum samples collected from 50 dolphins of all age groups, years 1998–2005. Predicted GFR was also calculated from serum collected from a 32‐yr‐old male dolphin with end‐stage renal disease. The dolphin‐adjusted MDRD equation predicted GFR changes in our population that paralleled what has previously been reported in other mammals, including decreasing predicted GFR with age (P < 0.01), higher predicted GFR in dolphins that had recently eaten (P < 0.01), and rapidly decreasing predicted GFR in the animal with end‐stage renal disease. We conclude that a serum‐based GFR prediction equation may be a feasible means of detecting and tracking renal function in bottlenose dolphins.     

The effects of cortisol and testosterone on renal function in male Antechinus stuartii (Marsupialia)

Seasonal changes in the physiology of Antechinus stuartii result in complete male mortality after mating. The most important endocrine changes in males are large rises in plasma testosterone and cortisol concentrations. Glomerular filtration rate (GFR) in males declines coincident with high plasma testosterone and cortisol. In the present study GFRs were measured in males captured in May (when endogenous plasma testosterone and cortisol levels are low) and given depot injections of either saline, testosterone-only, cortisol-only or testosterone plus cortisol at doses designed to mimic plasma levels during the mating period. GFR decreased significantly with testosterone injection, independent of cortisol treatment. Urinary concentrations of sodium and chloride, and osmolality decreased significantly with cortisol treatment, although the addition of testosterone reversed the effect. Total urinary excretion of electrolytes was similar between groups. Plasma potassium levels significantly increased in testosterone plus cortisol treated males. Plasma sodium levels significantly increased and plasma chloride significantly decreased in all groups treated with cortisol. Water consumption significantly increased in all cortisol-treated males and food consumption significantly increased in all testosterone-treated males. The seasonal renal functional changes observed in A. stuartii were mimicked by testosterone administration. Accepted: 23 January 1998     

The effects of urea infusion on glomerular filtration rate and renal plasma flow in sheep fed low and high protein diets.

Reducing the dietary N intake of sheep resulted in a significant fall in GFR with no change in RPF. Intravenous of urea for 19-46 h had no effect on the high protein diet but on the low protein diet GFR and FF were increased to values approaching those observed on the high protein diet. On the low protein diet GFR was unaffected by infusion of urea for 4 h or of saline alone for 30 h. It is suggested that the observed changes in GFR are associated with changes in the quantity of protein passing to the abomasum and small intestine.