scholarly journals II. DIFFERENCES IN ADRENAL MEDULLA NUCLEAR DNA CONTENT AMONG RATS OF DIFFERENT STRAINS FOLLOWING INTERMITTENT EXPOSURE TO COLD

1969 ◽  
Vol 42 (2) ◽  
pp. 452-459 ◽  
Author(s):  
Roberto Tongiani ◽  
Maria Pia Viola-Magni
Keyword(s):  
Adrenal Medulla ◽  
Wistar Rats ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Sprague Dawley ◽  
Exposure To Cold ◽  
Intermittent Exposure ◽  
Dna Loss ◽  
Long Evans ◽  
Different Strains

The amount of DNA per nucleus in the adrenal medulla cells of four different strains of rats (Wistar, Sprague-Dawley, Long-Evans, and Italico) is determined both under control conditions and after 300 hr of intermittent exposure to cold. The adrenal medulla nuclei of the four strains of rats contain the same amount of DNA; however, the loss of DNA observed after the same experimental treatment differs markedly in the different strains. The loss is small in Wistar and Sprague-Dawley rats (8–13%), larger in Long-Evans rats (20%) and still larger in Italico rats (45%). The DNA loss in Wistar rats increases if the animals are fed the same diet as the Italico rats, and the DNA loss in Italico rats is reduced if the animals are fed the same diet as the Wistar rats. The different behavior of the four strains is discussed in terms of turnover of DNA.

Ultrastructural Investigation of Spontaneous Pituitary Adenomas in Aging Sprague-Dawley Rats

1982 ◽  
Vol 40 ◽  
pp. 216-217
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs
Keyword(s):  
Microscopic Study ◽  
Pituitary Adenomas ◽  
Wistar Rats ◽  
Microscopic Level ◽  
Sprague Dawley ◽  
Prolactin Cells ◽  
Light Microscopic Level ◽  
Ultrastructural Investigation ◽  
Sprague Dawley Rats ◽  
Long Evans

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.

scholarly journals III. DECREASE OF LABELED DNA IN CELLS OF THE ADRENAL MEDULLA AFTER INTERMITTENT EXPOSURE TO COLD

1969 ◽  
Vol 42 (2) ◽  
pp. 460-468 ◽  
Author(s):  
S. R. Pelc ◽  
Maria Pia Viola-Magni
Keyword(s):  
Dna Synthesis ◽  
Mitotic Index ◽  
Adrenal Medulla ◽  
Room Temperature ◽  
Statistical Evaluation ◽  
Cold Treatment ◽  
Labeling Index ◽  
Initial Value ◽  
Exposure To Cold ◽  
Intermittent Exposure

Italico rats were injected with thymidine-3H 6 hr after the end of 300 hr of intermittent cold treatment. This plan of experiment ensured replacement in the adrenal medulla of lost DNA which is specifically sensitive to cold treatment and has a labeling index sufficiently high for statistical evaluation. The labeling index in the adrenal medulla decreases to one-half of the initial value within 10 days in animals subjected to further intermittent cold treatment and within 32 days in animals kept at room temperature. The very low mitotic index and the absence of doubling of the labeling index show that the observed labeling cannot be ascribed to pre-mitotic DNA synthesis. The concept of metabolic DNA adequately explains the findings.

The Effect of Age and Strain Differences on the Incidence of Restraint-Induced Oral and Gastric Ulcers in Three Strains of Rats

1972 ◽  
Vol 51 (2) ◽  
pp. 619-625 ◽  
Author(s):  
D.K. Whittaker ◽  
T.R. Wilson
Keyword(s):  
Wistar Rats ◽  
Strain Differences ◽  
Gastric Ulcers ◽  
Sprague Dawley ◽  
Oral Ulcers ◽  
Sprague Dawley Rats ◽  
Different Strains ◽  
Strain Dependent ◽  
Effect Of Age

Restraint of different strains of rat has been shown to be capable of inducing both oral and gastric ulcers. Hooded Wistar rats were most susceptible to gastric ulcers, whereas Sprague-Dawley rats had the highest incidence of oral ulcers. The causative mechanisms probably differ and are strain dependent.

Strain and Sex Differences in Gastric Ulceration in Restrained Rats

1967 ◽  
Vol 16 (3) ◽  
pp. 310-316 ◽  
Author(s):  
T. R. Wilson
Keyword(s):  
Sex Differences ◽  
Wistar Rats ◽  
Physical Restraint ◽  
Gastric Ulceration ◽  
Female Rats ◽  
Ulcer Formation ◽  
Sprague Dawley ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Different Strains

SummaryMale and female rats of three different strains were subjected to physical restraint, when it was demonstrated that there is a relationship between the strain of the rat and its susceptibility to gastric ulcer formation. Severity of ulceration was greatest in Wistar rats. Hooded Wistar rats were also ulcer-susceptible, but not to such a great extent as Wistar animals. Sprague-Dawley rats were resistant to ulcer formation. Sex differences in ulcer severity were found only with restrained Hooded Wistar rats.The results of this investigation compare favourably with results published for individual strains of rats by other workers. It is possible that genetic influences may be responsible for the differences observed, but the way in which they operate is not understood.

Hypertension during chronic exposure to cold: comparison between Sprague–Dawley and Long–Evans strains

1992 ◽  
Vol 70 (5) ◽  
pp. 701-708 ◽  
Author(s):  
Anne Riesselmann ◽  
Andreas Baron ◽  
Melvin J. Fregly ◽  
Patricia van Bergen
Keyword(s):  
Blood Pressure ◽  
Adipose Tissue ◽  
Angiotensin Ii ◽  
Brown Adipose Tissue ◽  
Chronic Exposure ◽  
Sprague Dawley ◽  
Exposure To Cold ◽  
Brown Adipose ◽  
Induced Hypertension ◽  
Long Evans

It is now well established that chronic exposure of rats to cold (5–6 °C) induces an elevation of systolic, diastolic, and mean blood pressures and cardiac hypertrophy within 3 weeks. Since rats of the Long–Evans (LE) strain are known to be resistant to the induction of deoxycorticosterone salt induced hypertension, their cardiovascular responses to chronic exposure to cold were compared with those of rats of the Sprague–Dawley (SD) strain. The results of these studies revealed clear differences between the LE and SD strains of rats. Thus, rats of the SD strain had a significant elevation in their blood pressure; a significantly increased urinary output of norepinephrine and epinephrine; a significantly greater dipsogenic responsiveness to acute administration of angiotensin II, and significant increases in weights of the heart, kidneys, adrenals, and brown adipose tissue compared with their warm-adapted controls. All of these changes are characteristic of rats acclimated to cold. In contrast, rats of the LE strain appear to be less responsive to cold in that blood pressure failed to rise as sharply and to attain as high a level. Furthermore, urinary outputs of norepinephrine and epinephrine were significantly lower in cold-treated rats of the LE strain compared with cold-treated rats of the SD strain, but dipsogenic responsiveness to angiotensin II was unchanged. Although increases in the weight of the previously mentioned organs were also observed in cold-treated rats of the LE strain compared with their warm-adapted controls, weights of the heart and interscapular brown adipose tissue of both groups were significantly less than those of counterparts of the SD strain. Thus, the results show striking differences between the two strains and suggest that a reduced secretion of catecholamines by the LE strain may be a factor in the failure of the blood pressure of these rats to reach the level of cold-exposed rats of the SD strain. Additional studies will be required to verify this suggestion.Key words: strains of rats, Long–Evans, Sprague–Dawley, cold, cold-induced hypertension, blood pressure, angiotensin II induced drinking.

Interaction between nitric oxide and renal myogenic autoregulation in normotensive and hypertensive rats

2001 ◽  
Vol 79 (3) ◽  
pp. 238-245 ◽  
Author(s):  
Xuemei Wang ◽  
William A Cupples
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Wistar Rats ◽  
Fundamental Property ◽  
Brown Norway ◽  
Sprague Dawley ◽  
Spontaneously Hypertensive ◽  
Long Evans

Blood pressure fluctuates continuously throughout life and autoregulation is the primary mechanism that isolates the kidney from this fluctuation. Compared with Wistar rats, Brown Norway (B-N) rats display impaired renal myogenic autoregulation when blood pressure fluctuation is increased. They also are very susceptible to hypertension-induced renal injury. Because blockade of nitric oxide augments myogenic autoregulation in Wistar rats, we compared the response of the myogenic system in B-N rats to nitric oxide blockade with that of other strains [Wistar, Sprague-Dawley, Long-Evans, spontaneously hypertensive (SHR)]. Renal blood flow dynamics were assessed in isoflurane anesthetized rats before and after inhibition of nitric oxide synthase by Lω-nitro-arginine methyl-ester (L-NAME, 10 mg/kg, iv). Under control conditions, myogenic autoregulation in the B-N rats was weaker than in the other strains. Myogenic autoregulation was not augmented after L-NAME administration in the SHR, but was augmented in all the normotensive rats. The enhancement was significantly greater in B-N rats so that after L-NAME the efficiency of autoregulation did not differ among the strains. The data suggest that nitric oxide is involved in the impaired myogenic autoregulation seen in B-N rats. Furthermore, the similarity of response in Wistar, Long-Evans, and Sprague-Dawley rats suggests that modulation by nitric oxide is a fundamental property of renal myogenic autoregulation.Key words: renal blood flow, transfer function, dynamics, SHR, Wistar, Long-Evans, Sprague-Dawley, Brown-Norway, L-NAME.

Light and electron microscopic investigation of adenohypophyses of germfree, food-restricted, and germfree-food restricted aging, male lobund-wistar rats

1988 ◽  
Vol 46 ◽  
pp. 352-353
Author(s):  
G. Ilse ◽  
K. Kovacs ◽  
N. Ryan ◽  
T. Sano ◽  
L. Stefaneanu ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
Aging Male ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Sprague Dawley Rats ◽  
Old Rats ◽  
Ad Libitum ◽  
Microscopic Findings

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

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