Evidence of Multiple Hepatic Mechanisms to Mobilize Docosahexaenoic Acid into Dam Plasma during Pregnancy in chow-fed Sprague Dawley Rats

Author(s):  
Dan Chalil ◽  
Juan J. Aristizabal-Henao ◽  
Alan Chalil ◽  
Ken D. Stark
2019 ◽  
Vol 149 (3) ◽  
pp. 479-487 ◽  
Author(s):  
Zahra Farahnak ◽  
Julia Lévy-Ndejuru ◽  
Paula Lavery ◽  
Hope A Weiler

ABSTRACT Background Docosahexaenoic acid (DHA; 22:6n–3) is an n–3 (ω-3) fatty acid known for beneficial effects on body composition. Objective The objective of the study was to test the dose response of lean and fat mass to DHA in healthy growing female rats. Methods Female Sprague-Dawley rats (7 wk at baseline; n = 12/diet) were randomly assigned to receive a control (AIN-93M; 60 g soybean oil/kg diet) or experimental diet for 10 wk. Experimental diets contained 0.1%, 0.4%, 0.8%, or 1.2% DHA (wt:wt of total diet). Imaging for whole-body and abdominal composition was conducted using dual-energy X-ray absorptiometry and microcomputed tomography, respectively, at weeks 0, 5, and 10. Fatty acid profiles of several tissues were analyzed using gas chromatography. Serum leptin, C-reactive protein, and plasma insulin-like growth factor I concentrations were measured at each time point using immunoassays. Data were tested using Pearson's correlations and mixed-model ANOVA. Results No differences were observed in weight at baseline or food intake throughout the study. Overall, a 6% increase (P < 0.05) in whole-body and abdominal lean mass was observed in the 0.4%-DHA diet group compared with the control diet group. Moreover, the abdominal visceral fat mass was 31.4% lower in rats in the 0.4%-DHA than in the 1.2%-DHA diet group (P < 0.001). Rats in the 1.2%-DHA diet group showed greater percent differences in whole-body (32.5% and 40.6% higher) and in abdominal (33.9% and 49.4% higher) fat mass relative to the 0.1%- and 0.4%-DHA diet groups, respectively (P < 0.01). Accordingly, serum leptin concentration was lower in the 0.1%-DHA (38.2%) and 0.4%-DHA (43.8%) diet groups (P < 0.01) than in the 1.2%-DHA diet group and positively related to whole-body fat mass (r = 0.91, P < 0.0001). Conclusion Dietary DHA at 0.4% of dietary weight effectively enhances lean mass and proportionally reduces fat mass in growing female rats.


2000 ◽  
Vol 64 (12) ◽  
pp. 2588-2593 ◽  
Author(s):  
Pham HUNG ◽  
Jiong-Yan GU ◽  
Shihoko KAKU ◽  
Shin-ichi YUNOKI ◽  
Ken-ichi OHKURA ◽  
...  

Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs

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.


Author(s):  
F. G. Zaki ◽  
E. Detzi ◽  
C. H. Keysser

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.


Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.


Author(s):  
Russell N. A. Cecil ◽  
H. Clarke Anderson

Unfixed proximal tibial epiphyseal growth plates were studied by freeze-etch to confirm the presence of extracellular calcifying matrix vesicles and to determine the substructure of matrix vesicle membranes as compared to plasma and other membranes of intact chondrocytes. Growth plates from 6-10 week old Sprague-Dawley rats were cut into 1x3 mm blocks whose long dimension was oriented either perpendicular or parallel to the long axis of the tibia. Some blocks were fixed at pH 7. 0 in 0. 2M cacodylate - buffered 2. 5% glutaraldehyde for 1 hour at 4ÅC. The blocks were immersed in 30% glycerol solution at 4ÅC for 1 hour, frozen in liquid nitrogen, and then fractured, etched for 2 minutes, and coated with platinum, carbon and 0. 2% Formvar solution. The replicas were cleaned with chromic acid, floated onto Formvar coated grids, and examined with a Phillips EM 300 electron microscope.Fixed and unfixed specimens appeared similar in ultrastructure. Chondrocytes, matrix, and matrix vesicles were identified. In specimens fractured parallel to the long axis of the tibia, the reserve, proliferative, hypertrophic, and calcifying zones could be discerned as described by light and electron microscopy.


Author(s):  
M. Ashraf ◽  
L. Landa ◽  
L. Nimmo ◽  
C. M. Bloor

Following coronary artery occlusion, the myocardial cells lose intracellular enzymes that appear in the serum 3 hrs later. By this time the cells in the ischemic zone have already undergone irreversible changes, and the cell membrane permeability is variably altered in the ischemic cells. At certain stages or intervals the cell membrane changes, allowing release of cytoplasmic enzymes. To correlate the changes in cell membrane permeability with the enzyme release, we used colloidal lanthanum (La+++) as a histological permeability marker in the isolated perfused hearts. The hearts removed from sprague-Dawley rats were perfused with standard Krebs-Henseleit medium gassed with 95% O2 + 5% CO2. The hypoxic medium contained mannitol instead of dextrose and was bubbled with 95% N2 + 5% CO2. The final osmolarity of the medium was 295 M osmol, pH 7. 4.


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