Rat Strain and Sex Differences in Leptin Responses to Immobilization Stress

2006 ◽  
Vol 27 (3) ◽  
pp. 136-146 ◽  
Author(s):  
Rachel M. Ceballos ◽  
Martha M. Faraday ◽  
Laura Cousino Klein
Keyword(s):  
Immobilization Stress ◽  
Strain Differences ◽  
Baseline Period ◽  
Interactive Effects ◽  
Stress Exposure ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Rat Strain ◽  
Long Evans ◽  
Plasma Leptin

The effects of immobilization (IM) stress on plasma leptin levels and bodyweight in adult Sprague-Dawley (19 males, 20 females) and Long-Evans (20 males, 20 females) rats were investigated. Following a 10-day baseline period, half the animals from each experimental group were exposed to immobilization stress or no-stress 20 min/day for 21 days. Plasma leptin and corticosterone levels were measured following stress or no-stress exposure on the last day of the experiment. Corticosterone levels confirmed stress exposure. Important interactive effects of stress, strain, and sex on leptin and corticosterone levels were also observed. Specifically, females displayed higher leptin levels than did males, regardless of stress exposure. Strain interacted with stress such that stressed Long-Evans rats displayed higher leptin levels than did stressed Sprague-Dawley rats; there were no strain differences in leptin levels among nonstressed rats. Also, correlations between leptin and corticosterone were strain-specific. Results are discussed with respect to previously unreported strain differences in the effects of immobilization stress on circulating plasma leptin and the relevance to inconsistent findings in the human literature.

A new obesity-prone, glucose-intolerant rat strain (F.DIO)

2003 ◽  
Vol 285 (5) ◽  
pp. R1184-R1191 ◽  
Author(s):  
Barry E. Levin ◽  
Ambrose A. Dunn-Meynell ◽  
Julie E. McMinn ◽  
Michael Alperovich ◽  
Amy Cunningham-Bussel ◽  
...  
Keyword(s):  
Insulin Response ◽  
High Energy ◽  
Male Rats ◽  
Oral Glucose ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Rat Strain ◽  
Plasma Leptin ◽  
F344 Rats ◽  
Mode Of Inheritance

Previous breeding for the diet-induced obese (DIO) trait from outbred Sprague-Dawley rats produced a substrain with selection characteristics suggesting a polygenic mode of inheritance. To assess this issue further, selectively bred DIO male rats were crossed with obesity-resistant inbred Fischer F344 dams. Male offspring were crossed twice more against female F344 dams. The resultant N3 (F.DIO) rats were then inbred three more times. On low-fat chow, 10-wk-old male and female DIO rats weighed 86 and 59% more than respective F344 rats. By the N3 (F.DIO) generation, they were only 12 and 10% heavier, respectively. After three additional inbreeding cycles, chow-fed F.DIO males had an exaggerated insulin response to oral glucose compared with F344 rats. After 3 wk on a 31% fat (high-energy) diet, male N3 F.DIO rats gained 16-20% more carcass and adipose weight with 98% higher plasma leptin levels, whereas F.DIO females gained 36-54% more carcass and adipose weight with 130% higher leptin levels than comparable F344 rats. After three inbreeding cycles, F.DIO males still gained more weight on high-energy diet and developed a threefold greater insulin response to oral glucose than F344 males. Preservation of the DIO and glucose intolerance traits through successive backcrosses and inbreeding cycles to produce the F.DIO strain lends further support to the idea that they inherited in a polygenic fashion.

Hypertension with Mineralocorticoid Administration to the Long-Evans Rat

1979 ◽  
Vol 56 (2) ◽  
pp. 109-113 ◽  
Author(s):  
O. B. Holland ◽  
C. Gomez-Sanchez ◽  
T. Ziegler
Keyword(s):  
Sprague Dawley ◽  
Relative Resistance ◽  
Rat Strains ◽  
Deoxycorticosterone Acetate ◽  
Sprague Dawley Rats ◽  
Renal Enlargement ◽  
Rat Strain ◽  
Long Evans

1. The Carworth Long-Evans rat has been reported to develop adrenal-regeneration hypertension but not deoxycorticosterone acetate (DOCA) hypertension. Deficiency of a hypothalamic receptor for deoxycorticosterone which mediates saline polydipsia has been postulated to underlie this resistance. Since a mineralocorticoid etiology for adrenal-regeneration hypertension has been postulated and all mineralocorticoids are thought to act on common receptors, these previous reports are difficult to reconcile. 2. To determine if an absolute or relative resistance to mineralocorticoids is present, Charles River Long-Evans and Sprague-Dawley rats were given 40 mg (107 μmol) of DOCA pellets/rat or 250 μg (0·65 μmol) of 2α-methyl-9α-fluorocortisol/day subcutaneously. 3. Saline polydipsia occurred with both steroids with both rat strains, though significantly less with the Long-Evans rats. Both types of rats became hypertensive and developed cardiac and renal enlargement with both steroids. Hypertension developed more rapidly with 2α-methyl-9α-fluorocortisol. 4. Thus mineralocorticoid hypertension can be produced in the Charles River Long-Evans rat, and the development of adrenal-regeneration hypertension in this rat strain is not incompatible with a mineralocorticoid etiology for adrenal-regeneration hypertension.

scholarly journals Strain Differences in Response to Traumatic Brain Injury in Long-Evans Compared to Sprague-Dawley Rats

2009 ◽  
Vol 26 (4) ◽  
pp. 539-548 ◽  
Author(s):  
Arlene A. Tan ◽  
Andrea Quigley ◽  
Douglas C. Smith ◽  
Michael R. Hoane
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Strain Differences ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Long Evans

scholarly journals Strain differences in rat liver (UDP-glucuronyltransferase activity towards androsterone

1979 ◽  
Vol 179 (3) ◽  
pp. 483-487 ◽  
Author(s):  
M Matsui ◽  
F Nagai ◽  
S Aoyagi
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Strain Differences ◽  
Transferase Activity ◽  
Sprague Dawley ◽  
Freezing And Thawing ◽  
Sprague Dawley Rats ◽  
Long Evans ◽  
Triton X

Male Donryu, Wistar King rats showed discontinuous variations in hepatic microsomal UDP-glucuronyltransferase activities towards androsterone, but not towards testosterone, bilirubin, phenolphthalein and 4-nitrophenol. Fresh microsomal fraction with a low transferase activity towards androsterone formed 0.049–0.080 nmole of glucuronide/min per mg of protein, whereas fresh microsomal fraction with a high transferase activity towards androsterone formed 0.335–0.557 nmol of glucuronide/min per mg of protein. The microsomal fraction with low enzyme activity towards androsterone was not stimulated by treatment with Triton X-100 or freezing and thawing. In contrast, male Long Evans and Sprague-Dawley rats did not exhibit such diversity.

Nature of Infantile Shock Traumatization, Strain Differences, and Adaptability to Stress

1964 ◽  
Vol 14 (3) ◽  
pp. 775-779 ◽  
Author(s):  
Eugene F. Gauron
Keyword(s):  
Statistical Analysis ◽  
Field Test ◽  
Avoidance Conditioning ◽  
Open Field Test ◽  
Strain Differences ◽  
Early Experience ◽  
Sprague Dawley ◽  
Infant Rats ◽  
Sprague Dawley Rats ◽  
Long Evans

Infant rats of two strains were exposed to two types of shock traumatization in infancy: escapable and inescapable. The strains included Sprague-Dawley rats and Long-Evans hooded rats. Animals were tested in adulthood on open-field test, avoidance conditioning, and water escape maze. Statistical analysis yielded several significant Strain × Treatment interactions which suggest that strain of the animal and type of traumatization are potential influencing variables in the nature and direction of the effect produced by early traumatization. Such genetic and ontogenetic interaction complicates the issue of the nature of the effect produced by early experience.

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.

Defense of differfing body weight set points in diet-induced obese and resistant rats

1998 ◽  
Vol 274 (2) ◽  
pp. R412-R419 ◽  
Author(s):  
Barry E. Levin ◽  
Richard E. Keesey
Keyword(s):  
Body Weight ◽  
Diet Composition ◽  
Energy Homeostasis ◽  
Energy Content ◽  
Sprague Dawley ◽  
Fat Pad ◽  
Insulin Levels ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
Plasma Leptin

Among outbred Sprague-Dawley rats, approximately one-half develop diet-induced obesity (DIO) and one-half are diet resistant (DR) on a diet relatively high in fat and energy content (HE diet). Here we examined the defense of body weight in these two phenotypes. After HE diet for 13 wk, followed by chow for 6 wk, DR rats gained weight comparably but their plasma leptin levels fell to 54% of chow-fed controls. When a palatable liquid diet (Ensure) was added for 13 wk, other DR rats became obese. But when switched to chow, their intakes fell by 60%, and body and retroperitoneal (RP) fat pad weights and plasma leptin and insulin levels all declined for 2 wk and then stabilized at control levels after 6 wk. In contrast, comparably obese DIO rats decreased their intake by only 20%, and their weights plateaued when they were switched to chow after 13 wk on HE diet. When a subgroup of these DIO rats was restricted to 60% of prior intake, their weights fell to chow-fed control levels over 2 wk. But their leptin and insulin levels both fell disproportionately to 30% of controls. When no longer restricted, their intake and feed efficiency rose immediately, and their body and RP pad weights and leptin and insulin levels rose to those of unrestricted DIO rats within 2 wk. Thus diet and genetic background interact to establish high (DIO) or low (DR) body weight set points, which are then defended against subsequent changes in diet composition and/or energy availability. If leptin affects energy homeostasis, it does so differentially in DIO vs. DR rats since comparably low and high levels were associated with differing patterns of weight change between the two phenotypes.

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