Displaying publications 221 - 240 of 1281 in total

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  1. Looi LM, Loh KC
    Malays J Pathol, 2005 Jun;27(1):23-7.
    PMID: 16676689
    Although microwave irradiation has been used in the histopathology laboratory for several years, there has been minimal published experimental data on its effects on the technical and staining quality of histological sections. Furthermore, it has not been clear whether the advantages gained in reduction of fixation and staining duration has been at the expense of increasing architectural distortion to the tissues. We report here our experience with computerised morphometric analysis to investigate glomerular artifacts caused by microwave-stimulated fixation of renal tissues. 39 rat and 33 human autopsy kidney samples were subjected to (1) fixation in neutral buffered formaldehyde (control), (2) microwave-stimulated fixation followed by neutral buffered formaldehyde, and (3) neutral buffered formaldehyde followed by microwave irradiation. In addition, the effect of post-fixation in 70% ethanol was also investigated. Microwave irradiation was delivered through a dedicated laboratory microwave oven at 80% power and at 55 degrees C for 3 minutes. The different fixation methods were compared with regards to shrinkage (distortion) to glomerular structures (glomeruli and Bowman's spaces) on H and E sections, as determined by morphometric image analysis using a temporary assembled-system consisting of a trinocular microscope, a digital video camera and personal computer. A FlashPoint VGA 3.3 film-grabber card was used to capture images for morphometric analysis by using a Scion Image program. Morphometric analysis of glomerular structures showed that microwaves caused more shrinkage to the area bounded by the Bowman's capsule than the glomerulus proper, but post-fixation with ethanol reduced this shrinkage. These findings have implications on the logistics of tissue preparation of renal biopsies in clinical practice.
    Matched MeSH terms: Rats, Sprague-Dawley
  2. Low BS, Das PK, Chan KL
    J Ethnopharmacol, 2013 Feb 13;145(3):706-14.
    PMID: 23261482 DOI: 10.1016/j.jep.2012.11.013
    Eurycoma longifolia Jack, a small Simaroubaceae tree, known locally as 'Tongkat Ali' is popularly used as a sexual tonic in traditional medicine for aphrodisiac activity and improvement of fertility and male libido.
    Matched MeSH terms: Rats, Sprague-Dawley
  3. Elyagoby A, Layas N, Wong TW
    J Pharm Sci, 2013 Feb;102(2):604-16.
    PMID: 23225084 DOI: 10.1002/jps.23388
    Conventional fluid-bed and immersion film coating of hydrophilic zinc pectinate pellets by hydrophobic ethylcellulose is met with fast drug release. This study explored in situ intracapsular pellet coating for colon-specific delivery of 5-fluorouracil (5-FU). The solid coating powder constituted ethylcellulose and pectin in weight ratios of 11:0 to 2:9. Its weight ratio to pellets varied between 2:3 and 3:2. Pectin was used as excipient of core pellets and coating powder in view of its potential use in colon cancer treatment. Delayed 5-FU release and core pectin dissolution were attainable when the weight ratio of solid coating powder to pellets was kept at 3:2, and weight ratio of ethylcellulose and pectin in coating powder was kept at 8:3 with particle size of ethylcellulose reduced to 22 μm. In situ intracapsular wetting of pectin coat by dissolution medium resulted in the formation of ethylcellulose plug interconnecting with pellets through the binding action of pectin. Less than 25% of drug was released at the upper gastrointestinal tract. The majority of drug was released upon prolonged dissolution and in response to colonic enzyme pectinase, which digested core pellets.
    Matched MeSH terms: Rats, Sprague-Dawley
  4. Mahmood A, Omar MN, Ngah N
    Asian Pac J Trop Med, 2012 Nov;5(11):882-6.
    PMID: 23146802 DOI: 10.1016/S1995-7645(12)60164-3
    OBJECTIVE: To investigate the potential of Musa x paradisiaca (M. x paradisiaca) flower extracts in promoting milk production of lactating rats and its effects on growth of the suckling pups.

    METHODS: Galactagogue activity was evaluated in terms of quantity of milk produced from the rats treated with petroleum ether, ethanol or water extracts of the flower. Lactating rats (n = 5) of Spraque Dawley with six pups each were administered with the extracts in the amount of 500 mg/kg body weight, while the control rats were given an equivalent amount of distilled water. The rats were daily administered via oral feeding starting from Day 5 until Day 14 and the performance of milk production was measured along the experimental period by weight-suckle-weight method. Results were statistically analyzed using SPSS by means of ANOVA at 0.05 and was expressed as their mean?standard deviation. The rates of pups' growth were measured as the weight gain along the experimental period.

    RESULTS: The rats treated with aqueous extract produced higher milk than control and ethanol groups. Aqueous extract was identified to increase milk production by 25%, while petroleum ether extract by 18%. The mean of yields produced by the rats during suckling period for aqueous, petroleum ether, ethanol and control were 4.62±2.45, 4.37±1.93, 3.65±1.89 and 3.69±1.79, respectively. Growth rates of pups for the rats treated with control, aqueous, ethanol extract and petroleum ether were (1.85±0.49), (1.78±0.56), (1.65±0.46) and (1.56±0.42) g/pup, respectively.

    CONCLUSIONS: The present study reveals the potential of M. x paradisiaca flower to enhance milk production of nursing mothers which could be exploited for commercialization of the isolated extract.

    Matched MeSH terms: Rats, Sprague-Dawley
  5. Hanachi P, Loh LN, Fauziah O, Rafiuz ZH, Tee ST, Lye CW, et al.
    Med J Malaysia, 2004 May;59 Suppl B:208-9.
    PMID: 15468891
    Neem, Azadirachta indica, is a plant from the family Meliaceae, known as "Pokok Semambu" in Malay community. It has been extensively used in India as traditional Ayurvedic and folklore minedicine for the treatment of various diseases. This study aimed to determine the distribution of selenium in the liver of rats during hepatocarcinogenesis when neem aqueous extract and dietary selenium was supplemented.
    Matched MeSH terms: Rats, Sprague-Dawley
  6. Mohamed EA, Yam MF, Ang LF, Mohamed AJ, Asmawi MZ
    J Acupunct Meridian Stud, 2013 Feb;6(1):31-40.
    PMID: 23433053 DOI: 10.1016/j.jams.2013.01.005
    Orthosiphon stamineus is a popular folk medicine widely used to treat many diseases including diabetes. Previous studies have shown that the sub-fraction of chloroform extract was able to inhibit the rise of blood glucose levels in a glucose tolerance test. This study was carried out to evaluate the chronic effect and possible mechanism of action of the bioactive chloroform sub-fraction of O. stamineus using streptozotocin-induced diabetic rats and in vitro methods. Administration of the chloroform extract sub-fraction 2 (Cƒ2-b) at a dose of 1 g/kg twice daily on diabetic rats for 14 days showed a significant lowering (p < 0.05) of the final blood glucose level compared to the pretreatment level. However, there were no significant differences in the plasma insulin levels post-treatment compared to the pretreatment levels for all doses of Cƒ2-b. Conversely, Cƒ2-b at a concentration of 2 mg/mL significantly increased (p < 0.001) the glucose uptake by the rat diaphragm muscle. The increase in glucose uptake was also shown when the muscle was incubated in a solution containing 1 IU/mL of insulin or 1 mg/mL of metformin. Furthermore, the effect of this sub-fraction on glucose absorption in the everted rat jejunum showed that Cƒ2-b at concentrations of 0.5 mg/mL, 1 mg/mL and, 2 mg/mL significantly reduced the glucose absorption of the jejunum (p < 0.05-0.001). Similarly, the absorption of glucose was also inhibited by 1 mg/mL and 2 mg/mL of metformin (p < 0.001). These results suggest that the effect of Cƒ2-b may be due to extra-pancreatic mechanisms. There was no evidence that the plant extract stimulated the release of insulin in order to lower the blood glucose level.
    Matched MeSH terms: Rats, Sprague-Dawley
  7. Nikbakht Nasrabadi E, Jamaluddin R, Abdul Mutalib MS, Khaza'ai H, Khalesi S, Mohd Redzwan S
    J Appl Microbiol, 2013 May;114(5):1507-15.
    PMID: 23351087 DOI: 10.1111/jam.12148
    Aflatoxin B1 (AFB1 ) is considered as the most toxic food contaminant, and microorganisms, especially bacteria, have been studied for their potential to reduce the bioavailability of mycotoxins including aflatoxins. Therefore, this research investigated the efficacy of oral administration of Lactobacillus casei Shirota (LcS) in aflatoxin-induced rats.
    Matched MeSH terms: Rats, Sprague-Dawley
  8. Widyawati T, Yusoff NA, Asmawi MZ, Ahmad M
    Nutrients, 2015 Sep;7(9):7764-80.
    PMID: 26389944 DOI: 10.3390/nu7095365
    Syzygium polyanthum (S. polyanthum), a plant belonging to Myrtaceae, is widely used in Indonesian and Malaysian cuisines. Diabetic patients in Indonesia also commonly use it as a traditional medicine. Hence, this study was conducted to investigate the antihyperglycemic effect of the methanol extract (ME) of S. polyanthum leaf and its possible mechanisms of action. To test for hypoglycemic activity, ME was administered orally to normal male Sprague Dawley rats after a 12-h fast. To further test for antihyperglycemic activity, the same treatment was administered to glucose-loaded (intraperitoneal glucose tolerance test, IPGTT) and streptozotocin (STZ)-induced diabetic rats, respectively. Hypoglycemic test in normal rats did not show significant reduction in blood glucose levels (BGLs) by the extract. Furthermore, IPGTT conducted on glucose-loaded normal rats also did not show significant reduction of BGLs. However, repeated administration of metformin and three doses of ME (250, 500 and 1000 mg/kg) for six days caused significant reduction of fasting BGLs in STZ-induced diabetic rats. The possible mechanisms of action of S. polyanthum antihyperglycemic activity were assessed by measurement of intestinal glucose absorption and glucose uptake by isolated rat abdominal muscle. It was found that the extract not only inhibited glucose absorption from the intestine but also significantly increased glucose uptake in muscle tissue. A preliminary phytochemical qualitative analysis of ME indicated the presence of tannins, glycosides, flavonoids, alkaloids and saponins. Additionally, Gas Chromatography-Mass Spectrometry (GC-MS) analysis detected squalene. In conclusion, S. polyanthum methanol leaf extract exerts its antihyperglycemic effect possibly by inhibiting glucose absorption from the intestine and promoting glucose uptake by the muscles.
    Matched MeSH terms: Rats, Sprague-Dawley
  9. Khan NR, Wong TW
    Expert Opin Drug Deliv, 2016 09;13(9):1209-19.
    PMID: 27212391 DOI: 10.1080/17425247.2016.1193152
    OBJECTIVES: Skin drug retention is required in local treatment of skin cancer. This study investigated the interplay effects of ethosomes and microwave in transdermal drug delivery. Skin pre-treatment by microwave and applied with liquified medicine is deemed to 'cement' the skin thereby raising skin drug deposition.

    METHODS: 5-fluorouracil-loaded ethosomes were prepared and subjected to size, zeta potential, morphology, drug content, drug release and skin permeation tests. The molecular characteristics of untreated, microwave and/or ethosome-treated skins were examined by Fourier transform infrared and raman spectroscopy, thermal and electron microscopy techniques.

    RESULTS: The skin drug retention was promoted using larger ethosomes with negative zeta potentials that repelled anionic lipids of skin and hindered vesicle permeation into deep layers. These ethosomes had low ethanol content. They were less able to fluidize the lipid and defluidize the protein domains at epidermis to enlarge aqueous pores for drug permeation. Pre-treatment of skin by 2450 MHz microwave for 2.5 min further increased skin drug penetration and retention of low ethanol ethosomes and provided lower drug permeation than cases treated for 1.15 min and 5 min. A 2.5 min treatment might be accompanied by specific dermal protein fluidization via C=O moiety which translated to macromolecular swelling, narrowing of intercellular spaces at lower skin layers, increased drug retention and reduced drug permeation.

    CONCLUSION: Ethosomes and microwave synergized to promote skin drug retention.

    Matched MeSH terms: Rats, Sprague-Dawley
  10. Qian YS, Ramamurthy S, Candasamy M, Shadab M, Kumar RH, Meka VS
    Curr Pharm Biotechnol, 2016;17(6):549-55.
    PMID: 26813303
    CONTEXT: Kaempferol has a large particle size and poor water solubility, leading to poor oral bioavailability. The present work aimed to develop a kaempferol nanosuspension (KNS) to improve pharmacokinetics and absolute bioavailability.

    METHODS: A nanosuspension was prepared using high pressure homogenization (HPH) techniques. The physico-chemical properties of the kaempferol nanosuspension (KNS) were characterized using photon correlation spectroscopy (PCS), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and x-ray diffractometry (XRD). A reversephase high performance liquid chromatography (RP-HPLC) method for the analysis of the drug in rat plasma was developed and validated as per ICH guidelines. In vivo pharmacokinetic parameters of oral pure kaempferol solution, oral kaempferol nanosuspension and intravenous pure kaempferol were assessed in rats.

    RESULTS AND DISCUSSION: The kaempferol nanosuspension had a greatly reduced particle size (426.3 ± 5.8 nm), compared to that of pure kaempferol (1737 ± 129 nm). The nanosuspension was stable under refrigerated conditions. No changes in physico-chemical characteristics were observed. In comparison to pure kaempferol, kaempferol nanosuspension exhibited a significantly (P<0.05) increased in Cmax and AUC(0-∞) following oral administration and a significant improvement in absolute bioavailability (38.17%) compared with 13.03% for pure kaempferol.

    CONCLUSION: These results demonstrate enhanced oral bioavailability of kaempferol when formulated as a nanosuspension.

    Matched MeSH terms: Rats, Sprague-Dawley
  11. Yida Z, Imam MU, Ismail M, Ismail N, Hou Z
    Drug Des Devel Ther, 2015;9:3951-9.
    PMID: 26251574 DOI: 10.2147/DDDT.S87772
    Edible bird's nest (EBN) is popular in Asia, and has long been used traditionally as a supplement. There are, however, limited evidence-based studies on its efficacy. EBN has been reported to improve dyslipidemia, which is closely linked to hypercoagulation states. In the present study, the effects of EBN on high-fat diet- (HFD-) induced coagulation in rats were evaluated. Rats were fed for 12 weeks with HFD alone or in combination with simvastatin or EBN. Food intake was estimated, and weight measurements were made during the experimental period. After sacrifice, serum oxidized low-density lipoprotein (oxLDL), adiponectin, leptin, von willibrand factor, prostacyclin, thromboxane and lipid profile, and whole blood coagulation indices (bleeding time, prothrombin time, activated partial thromboplastin time, red blood count count, and platelet count) were estimated. Furthermore, hepatic expression of coagulation-related genes was evaluated using multiplex polymerase chain reaction. The results indicated that EBN could attenuate HFD-induced hypercholesterolemia and coagulation similar to simvastatin, partly through transcriptional regulation of coagulation-related genes. The results suggested that EBN has the potential for lowering the risk of cardiovascular disease-related hypercoagulation due to hypercholesterolemia.
    Matched MeSH terms: Rats, Sprague-Dawley
  12. Chinigarzadeh A, Muniandy S, Salleh N
    Environ Toxicol Pharmacol, 2015 Jul;40(1):39-48.
    PMID: 26068551 DOI: 10.1016/j.etap.2015.05.003
    Maintaining near normal uterine fluid pH is important for restoring uterine function after menopause. We hypothesized that genistein could restore uterine fluid pH via its effect on NHE expression. This study therefore investigated changes in uterine NHE-1, 2 and 4 expression under genistein influence. Ovariectomized female rats received genistein (25, 50 or 100mg/kg/day) for seven consecutive days. Uteri were harvested and NHE-1, 2 and 4 mRNA expression were analyzed by Real-time PCR while distribution of these transporters' protein was observed by immunohistochemistry. Expression of NHE-1, 2 and 4 mRNA increased with increasing doses of genistein which was antagonized by ICI 182780. Under genistein influence, NHE-1, 2 and 4 proteins were found to be distributed at apical membrane of endometrial luminal epithelia. Enhanced expression of NHE-1, 2 and 4 in ovariectomised rat uteri by genistein might help to restore pH of uterine fluid which could be useful for women after menopause.
    Matched MeSH terms: Rats, Sprague-Dawley
  13. Greenwood MP, Greenwood M, Paton JF, Murphy D
    Endocrinology, 2015 Aug;156(8):2905-17.
    PMID: 25961839 DOI: 10.1210/en.2015-1074
    The polyamines spermidine and spermine are small cations present in all living cells. In the brain, these cations are particularly abundant in the neurons of the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus, which synthesize the neuropeptide hormones arginine vasopressin (AVP) and oxytocin. We recently reported increased mRNA expression of antizyme inhibitor 1 (Azin1), an important regulator of polyamine synthesis, in rat SON and PVN as a consequence of 3 days of dehydration. Here we show that AZIN1 protein is highly expressed in both AVP- and oxytocin-positive magnocellular neurons of the SON and PVN together with antizyme 1 (AZ1), ornithine decarboxylase, and polyamines. Azin1 mRNA expression increased in the SON and PVN as a consequence of dehydration, salt loading, and acute hypertonic stress. In organotypic hypothalamic cultures, addition of the irreversible ornithine decarboxylase inhibitor DL-2-(difluoromethyl)-ornithine hydrochloride significantly increased the abundance of heteronuclear AVP but not heteronuclear oxytocin. To identify the function of Azin1 in vivo, lentiviral vectors that either overexpress or knock down Azin1 were stereotaxically delivered into the SON and/or PVN. Azin1 short hairpin RNA delivery resulted in decreased plasma osmolality and had a significant effect on food intake. The expression of AVP mRNA was also significantly increased in the SON by Azin1 short hairpin RNA. In contrast, Azin1 overexpression in the SON decreased AVP mRNA expression. We have therefore identified AZIN1, and hence by inference, polyamines as novel regulators of the expression of the AVP gene.
    Matched MeSH terms: Rats, Sprague-Dawley
  14. Zakaria ZA, Balan T, Mamat SS, Mohtarrudin N, Kek TL, Salleh MZ
    PMID: 25927982 DOI: 10.1186/s12906-015-0638-z
    Melastoma malabathricum L. (Melastomaceae) is a small shrub with various medicinal uses. The present study was carried out to determine the gastroprotective mechanisms of methanol extract of M. malabathricum leaves (MEMM) in rats.
    Matched MeSH terms: Rats, Sprague-Dawley
  15. Johnson KR, Hindmarch CC, Salinas YD, Shi Y, Greenwood M, Hoe SZ, et al.
    PLoS One, 2015;10(4):e0124523.
    PMID: 25897513 DOI: 10.1371/journal.pone.0124523
    Magnocellular neurons (MCNs) in the hypothalamo-neurohypophysial system (HNS) are highly specialized to release large amounts of arginine vasopressin (Avp) or oxytocin (Oxt) into the blood stream and play critical roles in the regulation of body fluid homeostasis. The MCNs are osmosensory neurons and are excited by exposure to hypertonic solutions and inhibited by hypotonic solutions. The MCNs respond to systemic hypertonic and hypotonic stimulation with large changes in the expression of their Avp and Oxt genes, and microarray studies have shown that these osmotic perturbations also cause large changes in global gene expression in the HNS. In this paper, we examine gene expression in the rat supraoptic nucleus (SON) under normosmotic and chronic salt-loading SL) conditions by the first time using "new-generation", RNA sequencing (RNA-Seq) methods. We reliably detect 9,709 genes as present in the SON by RNA-Seq, and 552 of these genes were changed in expression as a result of chronic SL. These genes reflect diverse functions, and 42 of these are involved in either transcriptional or translational processes. In addition, we compare the SON transcriptomes resolved by RNA-Seq methods with the SON transcriptomes determined by Affymetrix microarray methods in rats under the same osmotic conditions, and find that there are 6,466 genes present in the SON that are represented in both data sets, although 1,040 of the expressed genes were found only in the microarray data, and 2,762 of the expressed genes are selectively found in the RNA-Seq data and not the microarray data. These data provide the research community a comprehensive view of the transcriptome in the SON under normosmotic conditions and the changes in specific gene expression evoked by salt loading.
    Matched MeSH terms: Rats, Sprague-Dawley
  16. Khan SA, Sattar MZ, Abdullah NA, Rathore HA, Abdulla MH, Ahmad A, et al.
    Acta Physiol (Oxf), 2015 Jul;214(3):390-401.
    PMID: 25846561 DOI: 10.1111/apha.12499
    AIM:
    This study investigated the role of the renal innervation in arterial and cardiopulmonary baroreflex regulation of renal sympathetic nerve activity (RSNA) and heart rate (HR) in rats fed a high-fat diet to induce obesity.

    METHODS:
    Rats received either a normal (12% kcal) or high (45% kcal) fat diet for 60 days. On day 61, rats were anesthetized and prepared for recording left RSNA. In one group, the renal nerves remained intact, while in the other, both kidneys were denervated. Baroreflex gain curves for RSNA and HR were generated by increasing and decreasing blood pressure. Low-pressure baroreceptors were challenged by infusing a saline load.

    RESULTS:
    Mean blood pressure was 135 mmHg in the fat-fed and 105 mmHg (P < 0.05) in normal rats. Weight gain, adiposity index and creatinine clearance were 37, 82 and 55% higher (P < 0.05-0.001), but urine flow rate and fractional sodium excretions were 53 and 65% (both P < 0.001) lower, respectively, in the fat-fed compared to normal rats. In fat-fed rats with innervated kidneys, RSNA and HR arterial baroreflex sensitivities were reduced by 73 and 72% (both P < 0.05) but were normal in renally denervated rats. Volume expansion decreased RSNA by 66% (P < 0.001) in normal rats, but not in the intact fat-fed rats and by 51% (P < 0.01) in renally denervated fat-fed rats.

    CONCLUSION:
    Feeding a high-fat diet caused hypertension associated with dysregulation of the arterial and cardiopulmonary baroreflexes which was dependent on an intact renal innervation. This suggests that in obese states neural signals arising from the kidney contribute to a deranged autonomic control.

    KEYWORDS:
    baroreflex gain curves; cardiopulmonary reflex; high-fat diet
    Matched MeSH terms: Rats, Sprague-Dawley
  17. Lim LW, Prickaerts J, Huguet G, Kadar E, Hartung H, Sharp T, et al.
    Transl Psychiatry, 2015;5:e535.
    PMID: 25826110 DOI: 10.1038/tp.2015.24
    Deep brain stimulation (DBS) is a promising therapy for patients with refractory depression. However, key questions remain with regard to which brain target(s) should be used for stimulation, and which mechanisms underlie the therapeutic effects. Here, we investigated the effect of DBS, with low- and high-frequency stimulation (LFS, HFS), in different brain regions (ventromedial prefrontal cortex, vmPFC; cingulate cortex, Cg; nucleus accumbens (NAc) core or shell; lateral habenula, LHb; and ventral tegmental area) on a variety of depressive-like behaviors using rat models. In the naive animal study, we found that HFS of the Cg, vmPFC, NAc core and LHb reduced anxiety levels and increased motivation for food. In the chronic unpredictable stress model, there was a robust depressive-like behavioral phenotype. Moreover, vmPFC HFS, in a comparison of all stimulated targets, produced the most profound antidepressant effects with enhanced hedonia, reduced anxiety and decreased forced-swim immobility. In the following set of electrophysiological and histochemical experiments designed to unravel some of the underlying mechanisms, we found that vmPFC HFS evoked a specific modulation of the serotonergic neurons in the dorsal raphe nucleus (DRN), which have long been linked to mood. Finally, using a neuronal mapping approach by means of c-Fos expression, we found that vmPFC HFS modulated a brain circuit linked to the DRN and known to be involved in affect. In conclusion, HFS of the vmPFC produced the most potent antidepressant effects in naive rats and rats subjected to stress by mechanisms also including the DRN.
    Matched MeSH terms: Rats, Sprague-Dawley
  18. Pertiwi AK, Kwan TK, Gower DB
    J Steroid Biochem Mol Biol, 2002 Aug;81(4-5):363-7.
    PMID: 12361726
    The intracellular movements of pregnenolone in rat testes were investigated. Whole testes were incubated in the presence or absence of pregnenolone (2.5mM) in the medium for 120 min (in some studies 30, 60, and 90 min). The testes were homogenised, subcellular fractions prepared and analysed in quadruplicate for steroid content by gas chromatography-mass spectrometry with selected ion monitoring. Quantification of pregnenolone and 11 of its metabolites, obtained from non-incubated whole testes, provided values for endogenous amounts. Pregnenolone was the only steroid of quantitative importance found initially in the mitochondrial fraction but was subsequently found in the microsomal fraction, where metabolism occurred. Identification and quantification of metabolites indicated that both classical pathways for testosterone production were operating, with the 4-en-3-oxosteroid pathway predominating. By 120 min, virtually all pregnenolone metabolites, including pregnenolone itself, were found in the cytosol, consistent with an overall movement from mitochondria to endoplasmic reticulum to cytosol.
    Matched MeSH terms: Rats, Sprague-Dawley
  19. Ruszymah BH, Zaiton Z, Aminuddin S, Khalid BA
    Exp. Clin. Endocrinol. Diabetes, 2001;109(4):227-30.
    PMID: 11453035
    The aim of this study was to investigate the effect of altered thyroid status on 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD type 1) and type 2 (11beta-HSD type 2) bioactivity in rat kidney and colon. Male Sprague-Dawley rats (250 g) were treated with either L-thyroxine (T4) or propylthiouracil (PTU) for 4 weeks. Blood were then analysed for serum thyroxine, sodium (Na+) and potassium (K+). The kidneys and colon were assayed for 11beta-HSD type 1 and 11beta-HSD type 2 bioactivity. In T4 treated rats the serum thyroxine was significantly elevated (p<0.05) whilst PTU decreased serum thyroxine significantly (p<0.001) compared to controls. Serum Na+ and K+ were within normal limits. There were no significant changes in 11beta-HSD type 1 bioactivity in both treatment groups compared to controls. However, the 11beta-HSD type 2 bioactivity in rats given thyroxine was significantly higher in the colon (p<0.003) compared to controls. We conclude that altered thyroid status had no effect on 11beta-HSD type 1 bioactivity but 11beta-HSD type 2 bioactivity was elevated in the colon of rats given supplementary thyroxine.
    Matched MeSH terms: Rats, Sprague-Dawley
  20. Ainsah O, Nabishah BM, Osman CB, Khalid BA
    PMID: 10595599
    Normal rats, on being repetitively stressed by being restrained in a tight container for two hours, had higher levels of plasma corticosterone compared to pre stress values. These rats also reacted to the stress by a behavioral response in which there was marked decrease in locomotor activity assessed by the open field test (pre stress: 71.3 +/- 2.6 squares crossed versus post stress: 14.3 +/- 2.5 squares crossed) by counting the number of squares entered by the rat over 5 minutes. By the 6th to 7th exposures to the repetitive stress, the rats adapted to the stress and had normal plasma corticosterone levels and locomotor activity scores comparable to the pre stress values. These responses to stress were completely blocked by the administration of 0.32 microg/100 g BW of naloxone i.p at 10 minutes prior to the stress. In rats fed with rat chow supplemented with 90 mg/kg rat chow or 150 mg/kg rat chow of vitamin E, there was significant reduction of the plasma corticosterone levels and improvement in the locomotor activity. Stress thus caused opioid mediated increase in plasma corticosterone and reduction in locomotor activity which could be blocked by naloxone. These stress responses probably also involved generation of oxygen free radicals which were scavenged by the vitamin E, thus reducing the effects of repetitive stress on locomotor activity and serum corticosterone levels.
    Matched MeSH terms: Rats, Sprague-Dawley
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