Influence of streptozotocin-induced diabetes and insulin on the functional capacity of rats

Male Sprague-Dawley rats were assigned to three groups designated as diabetic, diabetic-plus-insulin, and control and tested for maximum oxygen consumption (VO2max) and maximum heart rate on three different occasions during the 6- to 8-wk experimental period. Compared with the prediabetic values and the means of the other two groups, diabetic animals had significantly higher submaximum and lower maximum VO2 values. These relationships prevailed when the groups were evaluated in terms of ml.kg-1.min-1 or ml.(kg0.79-1).min-1. In addition, the diabetic animals had significantly lower submaximum and maximum heart rates and shorter run times. Daily injections of insulin (2 U.day-1.rat-1) restored VO2max to within the limits of the control animals but did not normalize heart rates or run-time values. The linear relationship between heart rates and VO2 was repeatedly demonstrated with normal animals. However, this relationship progressively declined with the time course of diabetes. These results indicate that, in untreated diabetes, functional capacity is markedly reduced with the progression of the disease and suggest that alterations in the autonomic nervous system, tissue metabolic capacity, and decreases in lean body mass are responsible for the changes noted.

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Effects of 6-mercaptopurine treatment on the membrane potentials of rat skeletal muscle fibers

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y85-211 ◽

1985 ◽

Vol 63 (10) ◽

pp. 1271-1278

Author(s):

Phyllis Clouva-Molyvdas ◽

Nicholas Sperelakis ◽

Michael S. Forbes ◽

Frederic R. Alleva ◽

Tibor Balazs

Keyword(s):

Membrane Potentials ◽

Sprague Dawley ◽

Sprague Dawley Rats ◽

Lower Amplitude ◽

Prolonged Duration ◽

Lower Maximum ◽

The Mean ◽

Edl Muscle ◽

And Control

6-Mercaptopurine (6-MP), injected daily (2 mg/kg s.c.) into Sprague–Dawley rats during the first 3 weeks of life, causes atrophy in muscles of the hindquarters beginning at 4 months of age. The extensor digitorium longus (EDL) muscles from 24 rats injected with 6-MP and 23 saline-injected controls, 6–18 months of age, were studied. Electron microscopy showed a number of abnormalities in the EDL muscle of 6-MP-treated rats, such as myocytes with atypical ultrastructure (including disorganized myofibrils) adjacent to structurally normal cells. Membrane potentials (Em) were measured in the isolated EDL and in the caudofemoralis (CF) muscle in situ. The mean Em of fibers in the EDL of 6-MP-treated rats (−61.1 ± 0.7 (SE) mV) was lower than that of the control rats (−69.7 ± 0.6 mV). The same was true for the fibers of the CF muscle (−64.9 ± 1.5 mV for 6-MP-treated fibers vs. −71.6 ± 1.3 mV for controls). The contribution of the electrogenic pump potential to Em (± ouabain) was similar in 6-MP-treated and control rats, and therefore could not account for the depolarization observed in 6-MP-treated rats. This depolarization was not due to a decreased intracellular K+ concentration. The Na+:K+ permeability ratio (PNa/PK) was higher in the 6-MP-treated rats and could account for the decrease in Em. The action potentials (APs) of 6-MP-treated rats (elicited from the natural Em of the fiber) had lower maximum rate of rise [Formula: see text] (330 ± 20 vs. 391 ± 17 V/s in controls), and lower amplitude (65.1 ± 2.9 vs. 73.3 ± 1.8 mV). When hyperpolarized to −90 mV before eliciting the AP, fibers from 6-MP-treated rats had depressed [Formula: see text] (382 ± 19 vs. 511 ± 21 V/s in controls), depressed AP amplitudes (97.0 ± 2.1 vs. 105.1 ± 1.6 mV), and prolonged duration at 50% amplitude (APD50) (0.66 ± 0.03 vs. 0.60 ± 0.02 ms). These data demonstrate definite electrophysiological and ultrastructural abnormalities in the EDL muscle of 6-MP-treated rats, resembling those observed in murine muscular dystrophy.

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Influence of simulated microgravity on the VO2 max of nontrained and trained rats

Journal of Applied Physiology ◽

10.1152/jappl.1993.74.4.1941 ◽

1993 ◽

Vol 74 (4) ◽

pp. 1941-1947 ◽

Cited By ~ 9

Author(s):

C. R. Woodman ◽

K. A. Monnin ◽

L. A. Sebastian ◽

C. M. Tipton

Keyword(s):

Simulated Microgravity ◽

Experimental Period ◽

Mechanical Efficiency ◽

Treadmill Running ◽

Microgravity Environment ◽

Maximum Oxygen Consumption ◽

Sprague Dawley ◽

Electrolyte Excretion ◽

Vo2 Max ◽

Sprague Dawley Rats

Head-down suspension (HDS) of rats has evolved as a useful model for the simulation of a microgravity environment. Previous HDS experiments with rats have shown an impaired capacity to perform aerobic exercise as demonstrated by reductions in maximum oxygen consumption (VO2 max), treadmill run time (RT), and mechanical efficiency (ME) of treadmill running at submaximal conditions. To determine whether endurance training (TR) before HDS would modify exercise performance, male Sprague-Dawley rats were assigned to nontrained (NT) or TR groups for 6 wk and exposed to HDS or cage control (CC) conditions for 29 days. The rats were tested for VO2 max, RT, and ME before treatment and on days 7, 14, 21, and 28. In addition, water and electrolyte excretion was measured on days 1 and 21 of the experimental period. Before HDS, the TR rats had significantly higher measures of VO2 max (15%) and RT (22%) than the NT rats. On day 28, HDS was associated with significant reductions in absolute VO2 max (ml/min) in TR (-30%) and NT (-14%) rats. Relative VO2 max (ml.min-1.kg-1) was significantly reduced in TR (-15%) but not NT rats. Similar reductions in RT occurred in TR (-37%) and NT (-35%) rats by day 28. ME was reduced 22% in both TR and NT rats after 28 days of suspension. HDS elicited diuresis, natriuresis, and kaliuresis in TR rats after 21 days but not after 24 h. In contrast, HDS-NT rats exhibited no diuretic, natriuretic, or kaliuretic responses.(ABSTRACT TRUNCATED AT 250 WORDS)

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EFFECT OF EXPERIMENTALLY INDUCED THYROIDITIS ON BIOSYNTHESIS OF THYROXINE IN RATS

Acta Endocrinologica ◽

10.1530/acta.0.0620011 ◽

1969 ◽

Vol 62 (1) ◽

pp. 11-20 ◽

Cited By ~ 1

Author(s):

Colum A. Gorman ◽

James W. Anderson ◽

Eunice V. Flock ◽

Charles A. Owen ◽

Khalil G. Wakim

Keyword(s):

Intravenous Administration ◽

Hashimoto's Thyroiditis ◽

Sprague Dawley ◽

Thyroid Extract ◽

Histologic Appearance ◽

Gland Weight ◽

Sprague Dawley Rats ◽

Thyroid Glands ◽

And Control ◽

Experimentally Induced

ABSTRACT Thyroiditis was induced in Sprague-Dawley rats by repeated immunization with thyroid extract and Freund's adjuvant. Immunized and control animals were killed at intervals up to 6 hours after intravenous administration of 131I as iodide at 5, 8 and 10 weeks after the first injection. Radioiodinated compounds in the thyroid glands were identified chromatographically. Evidence of moderate thyroiditis was present (histologic appearance, gland weight, and protein-bound iodine-butanol-extractable iodine difference) but the rate of incorporation of radioiodide into thyroxine, the percentage of radioactivity in the gland as iodide, and the MIT/DIT ratio were not significantly different in immunized and control animals. The MIT/DIT ratio was found to vary with time after 131I administration in both immunized and control animals. These studies did not uncover a defect in organification of iodide in experimental thyroiditis similar to that described by others in humans with Hashimoto's thyroiditis.

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Lodenafil treatment in the monocrotaline model of pulmonary hypertension in rats

Jornal Brasileiro de Pneumologia ◽

10.1590/s1806-37132014000400010 ◽

2014 ◽

Vol 40 (4) ◽

pp. 421-424 ◽

Cited By ~ 8

Author(s):

Igor Bastos Polonio ◽

Milena Marques Pagliareli Acencio ◽

Rogério Pazetti ◽

Francine Maria de Almeida ◽

Bárbara Soares da Silva ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Experimental Model ◽

Ventricular Hypertrophy ◽

Right Heart Catheterization ◽

Heart Catheterization ◽

Sprague Dawley ◽

Control Groups ◽

Right Heart ◽

Sprague Dawley Rats ◽

And Control

We assessed the effects of lodenafil on hemodynamics and inflammation in the rat model of monocrotaline-induced pulmonary hypertension (PH). Thirty male Sprague-Dawley rats were randomly divided into three groups: control; monocrotaline (experimental model); and lodenafil (experimental model followed by lodenafil treatment, p.o., 5 mg/kg daily for 28 days) Mean pulmonary artery pressure (mPAP) was obtained by right heart catheterization. We investigated right ventricular hypertrophy (RVH) and IL-1 levels in lung fragments. The number of cases of RVH was significantly higher in the monocrotaline group than in the lodenafil and control groups, as were mPAP and IL-1 levels. We conclude that lodenafil can prevent monocrotaline-induced PH, RVH, and inflammation.

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Synergistic suppression of pre-perfusion of donor livers with recipient serum and cobra venom factor treatment on hyperacute rejection following liver xenotransplantation

Acta Cirurgica Brasileira ◽

10.1590/s0102-86502012000500004 ◽

2012 ◽

Vol 27 (5) ◽

pp. 301-305 ◽

Cited By ~ 1

Author(s):

Baohua Zhu ◽

Chuanming Tong ◽

Weitao Guo ◽

Rong Pu ◽

Guoping Zhang ◽

...

Keyword(s):

Survival Time ◽

Hyperacute Rejection ◽

Cobra Venom ◽

Control Group ◽

Sprague Dawley ◽

Donor Liver ◽

Cobra Venom Factor ◽

Sd Rats ◽

Sprague Dawley Rats ◽

And Control

PURPOSE: To investigate synergistic suppression of donor liver pre-perfusion with recipient serum (RS) and cobra venom factor (CVF) treatment on hyperacute rejection (HAR) following liver xenotransplantation. METHODS: Guinea-pigs (GP, n=24) and Sprague-Dawley rats (SD, n=24) were recruited. Before transplantation, serum was collected from SD rats and used for preparation of inactivated complements. GP and SD rats were randomly assigned into four groups (n=6), respectively: RS group, CVF group, RS+CVF group and control group. Orthotopic liver xenotransplantation was performed with modified two-cuff technique. The survival time and liver function of recipients, morphological and pathological changes in rat livers were investigated. RESULTS: There was no piebald like change in the recipient livers in all experiment groups. The survival time of recipients in all experiment groups was longer than that in control group (p<0.05). Moreover, the survival time in the RS+CVF group was markedly longer than that in the RS group (p<0.01) and CVF group (p<0.05). The serum ALT level in all experiment groups were lower than that in the control group (p<0.05). Furthermore, the ALT level in the RS+CVF group was significantly lower than that in the CVF group (p<0.05) and RS group (p<0.01). The histological damages were significantly improved when compared with the control group, and the histological damages in the RS+CVF group were milder than those in the remaining groups (p<0.05) CONCLUSION: Pre-perfusion of donor liver with recipient serum and cobra venom factor treatment can exert synergistic suppressive effects on the hyperacute rejection following liver xenotransplantation.

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Changes in total body calcium balance with exercise in the rat

Journal of Applied Physiology ◽

10.1152/jappl.1983.55.1.201 ◽

1983 ◽

Vol 55 (1) ◽

pp. 201-204 ◽

Cited By ~ 16

Author(s):

A. D. LeBlanc ◽

H. J. Evans ◽

P. C. Johnson ◽

S. Jhingran

Keyword(s):

Least Squares ◽

Voluntary Exercise ◽

Calcium Balance ◽

Sprague Dawley ◽

Total Body Calcium ◽

Sprague Dawley Rats ◽

Least Squares Fit ◽

Significant Change ◽

Total Body ◽

And Control

The purpose of this study was to evaluate the effect of deconditioning on the total body calcium in rats. Two separate experiments were performed using female Sprague-Dawley rats, 187-266 days of age. Total body calcium was measured in experimental and control rats during and following several weeks of voluntary exercise. The slope from the least-squares fit of total body calcium with time was used to obtain an average calcium balance for each animal during each study period. In both groups the exercised rats had a significantly decreased calcium balance after cessation of exercise, whereas no significant change was seen in nonexercised controls. In both groups, the exercised animals gained calcium at a significantly greater rate than controls. Our findings indicate that while exercised rats may gain calcium at a faster rate compared with nonexercising controls, the rate of gain following cessation of exercise is less than the controls.

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TRANSFERSOME GEL FORMULATION OF AN ETHANOL EXTRACT OF APPLES (MALUS DOMESTICA MILL) CONTAINING ANTIOXIDANTS AND IN VITRO PENETRATION TESTING USING FRANZ DIFFUSION CELLS

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2017.v9s1.19_24 ◽

2017 ◽

Vol 9 ◽

pp. 32 ◽

Cited By ~ 1

Author(s):

Nurarita Fadila Zesiorani ◽

Effionora Anwar

Keyword(s):

Ethanol Extract ◽

Sprague Dawley ◽

Diffusion Cells ◽

Sprague Dawley Rats ◽

Apple Peel ◽

Franz Diffusion Cells ◽

Drug Efficiency ◽

And Control ◽

Peel Extract

Objective: This study aims to formulate and characterize a transfersome apple peel extract, formulate it into a gel, and compare it with a control gelmade without transfersome.Methods: Both gels were evaluated, stability tested, and penetration tested using Franz diffusion cells on the skin of female Sprague-Dawley rats. Thetransfersome preparations were formulated with different concentrations of the active substance, quercetin: 0.5% (F1); 0.7% (F2), and 1.0% (F3).Results: Based on the characterization results, F1 was selected as the optimum gel formulation because it had spherical morphology, a Dmean volume of106.44±2.70 nm, a polydispersity index of 0.078±0.01, a zeta potential of −49.96±2.05 mV, and a drug efficiency entrapment percentage of 78.78±0.46%.The cumulative amount of quercetin that was penetrated with the transfersome gel was 1514.41±26.31 μg/cm2, whereas the penetration with thecontrol gel extract was 1133.62±18.96 μg/cm2. The cumulative percentages of the penetrated gel transfersome and gel extract were 78.40±1.89%and 49.89±0.88%, respectively. The fluxes of transfersome gel and control gel extract were 52.33±0.11 μg/cm²/hrs and 40.89±0.68 μg/cm²/hrs,respectively.Conclusions: Based on these results, it can be concluded that the gel with transfersome exhibited better penetration than the gel extract alone.

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Distribution and metabolism of corticotropin-releasing factor in the rat

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y86-113 ◽

1986 ◽

Vol 64 (6) ◽

pp. 683-688 ◽

Cited By ~ 3

Author(s):

Bernard Candas ◽

Josée Lalonde ◽

Maurice Normand

Keyword(s):

Time Course ◽

Corticotropin Releasing Factor ◽

Metabolic Clearance ◽

Sprague Dawley ◽

Rapid Injection ◽

Sprague Dawley Rats ◽

Significant Difference ◽

The Mean ◽

The Moment ◽

The One

To develop a mathematical model of the distribution and metabolism of rat corticotropin-releasing factor (rCRF), the time course of 125I-labelled rCRF in plasma was measured in male Sprague–Dawley rats (i) following a rapid injection of 24 ng rCRF/100 g body weight (BW), or (ii) following a rapid injection of 424 ng rCRF/100 g BW, or (iii) during an infusion at a rate ranging from 0.28 to0.73 ng rCRF∙min−1∙100 g BW−1. The comparison of the one-, two-, and three-compartment models shows that the two-pool structure fits better to the dynamics of CRF in plasma as measured in each rat. Following a rapid injection the decay curve occurs in a biphasic manner; the early phase of disappearance is 25 times faster than the late one. There is no significant difference between the estimates of the metabolic clearance rate following both amplitudes of injection (0.40 ± 0.06 and 0.48 ± 0.05 mL∙min−1∙100 g BW−1). The volume of the first pool, 16.8 ± 1.1 mL/100 g BW, is four times larger than the plasma volume. It would thus appear that CRF is rapidly distributed from plasma into several tissues which are represented in the first pool of the model. The mean residence time of every CRF molecule in the second compartment, from the moment of secretion to its elimination, is from three to four times longer than in the first one. It stays, on average, between 140 min and 3 h in the system before an irreversible exit. At steady state, the disposal rate represents only 3% of the CRF mass of the first compartment every minute. These results could explain the prolonged effects of CRF on pituitary-adrenocortical secretion.

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Lung Cancer Incidence After Exposure of Rats to Low Doses of Radon: Influence of Dose Rate

Radiation Protection Dosimetry ◽

10.1093/oxfordjournals.rpd.a082429 ◽

1994 ◽

Vol 56 (1-4) ◽

pp. 93-97 ◽

Cited By ~ 13

Author(s):

J.P. Morlier ◽

M. Morin ◽

G. Monchaux ◽

P. Fritsch ◽

J.F. Pineau ◽

...

Keyword(s):

Lung Cancer ◽

Dose Rate ◽

Cancer Incidence ◽

Lung Cancer Incidence ◽

Sprague Dawley ◽

Survival Times ◽

Radon Exposure ◽

Sprague Dawley Rats ◽

Low Levels ◽

And Control

Abstract To study the effect on lung cancer incidence of a long exposure to low levels of radon, 500 male 3-month-old Sprague-Dawley rats, were exposed to a cumulative dose of 25 WLM of radon and its daughters, 6 hours a day, 5 days a week, during 18 months. Exposure conditions were controlled in order to maintain a defined PAEC: 42 x 10-6 J.m-3 (2 WL), in the range of domestic and environmental exposures. Animals were kept until they died or given euthanasia when moribund. Mean survival times were similar in both irradiated and control groups: 828 days (SD = 169) and 830 days (SD = 137), as well as lung cancer incidence, 0.60% at 25 WLM and 0.63% for controls. The incidence of lung lesions was compared statistically with controls and those previously obtained at cumulative exposures of 25 and 50 WLM delivered over a 4-6 month period, inducing a significant increase of lung cancer, 2.2% and 3.8% respectively. Such a comparison showed a decreased lung cancer incidence related to a decrease in the dose rate for low levels of radon exposure.

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