scholarly journals Adenosine A2A receptor modulation of juvenile female rat skeletal muscle microvessel permeability

2006 ◽  
Vol 291 (6) ◽  
pp. H3094-H3105 ◽  
Author(s):  
Jianjie Wang ◽  
Virginia H. Huxley
Keyword(s):  
Skeletal Muscle ◽  
Adenylyl Cyclase ◽  
Immunoblot Analysis ◽  
Reproductive Hormones ◽  
Female Rats ◽  
Female Rat ◽  
Rat Serum ◽  
Juvenile Female ◽  
Receptor Modulation ◽  
Microvessel Permeability

Little is known of the regulation of skeletal muscle microvascular exchange under resting or stimulating conditions. Adenosine (ADO) levels in skeletal muscle increase during physiological (exercise) and pathological (hypoxia, inflammation, and ischemia) conditions. Later stages of these pathologies are characterized by the loss of vascular barrier integrity. This study focused on determining which ADO receptor mediates the robust reduction in microvessel permeability to rat serum albumin ( PsRSA) observed in juvenile female rats. In microvessels isolated from abdominal skeletal muscle, ADO suffusion induced a concentration-dependent reduction in arteriolar [log(IC50) = −9.8 ± 0.2 M] and venular [log(IC50) = −8.4 ± 0.2 M] PsRSA. RT-PCR and immunoblot analysis demonstrated mRNA and protein expression of ADO A1, A2A, A2B, and A3 receptors in both vessel types, and immunofluorescence assay revealed expression of the four subtype receptors in the microvascular walls (endothelium and smooth muscle). PsRSA responses of arterioles and venules to ADO were blocked by 8-( p-sulphophenyl)theophylline, a nonselective A1 and A2 antagonist. An A2A agonist, CGS21680 , was more potent than the A1 agonist, cyclopentyladenosine, or the most-selective A2B agonist, 5′-( N-ethylcarboxamido)adenosine. The ability of CGS21680 or ADO to reduce PsRSA was abolished by the A2A antagonist, ZM241385. An adenylyl cyclase inhibitor, SQ22536, blocked the permeability response to ADO. In aggregate, these results demonstrate that, in juvenile females (before the production of the reproductive hormones), ADO enhances skeletal muscle arteriole and venule barrier function predominantly via A2A receptors using activation of adenylyl cyclase-signaling mechanisms.

scholarly journals Isolation and Quantification of Sphingosine and Sphinganine from Rat Serum Revealed Gender Differences

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 459 ◽  
Author(s):  
Graham Brogden ◽  
Diab M. Husein ◽  
Pablo Steinberg ◽  
Hassan Y. Naim
Keyword(s):  
High Performance ◽  
Gene Mutations ◽  
Female Rats ◽  
Sphingolipid Metabolism ◽  
Female Rat ◽  
Serum Samples ◽  
Fluorescence Detector ◽  
Rat Serum ◽  
Male And Female Rats ◽  
Significant Difference

Sphingolipids are an important group of lipids that play crucial roles in living cells, facilitating cell recognition, signal transduction and endocytosis. The concentration of sphingosine and some of its derivatives like sphinganine may serve as a biomarker for the diagnosis of sphingolipidoses or be used for further research into similar diseases. In this study, a sphingolipid extraction and a high resolution detection method specific for sphingosine and sphinganine was adapted and tested. Lipids were extracted from rats’ serum, coupled to o-phthalaldehyde and detected with a fluorescence detector after running through a silica gel column in a high performance liquid chromatography system. With this method, we analysed 20 male and 20 female rat serum samples and compared the concentrations of sphingosine and sphinganine. The results showed a significant difference between the sphingosine concentrations in the male and female rats. The sphingosine concentration in female rats was 805 ng/mL (standard deviation, SD ± 549), while that in males was significantly lower at (75 ng/mL (SD ± 40)). Furthermore, the sphingosine:sphinganine ratio was almost 15-fold higher in the females’ samples. The method presented here facilitates the accurate quantification of sphingosine and sphinganine concentrations down to 2.6 ng and 3.0 ng, respectively, and their ratio in small amounts of rat serum samples to study the sphingolipid metabolism and its potential modulation due to gene mutations or the effect of prevalent toxins.

scholarly journals Effects of leptin on gonadotropin secretion in juvenile female rat pituitary cells

2002 ◽  
pp. 261-266 ◽  
Author(s):  
M Tezuka ◽  
M Irahara ◽  
K Ogura ◽  
M Kiyokawa ◽  
T Tamura ◽  
...  
Keyword(s):  
Cultured Cells ◽  
Pubertal Development ◽  
Effective Concentration ◽  
Female Rats ◽  
Pituitary Cells ◽  
Female Rat ◽  
Serum Leptin ◽  
Juvenile Female ◽  
Physiological Serum ◽  
Old Rats

OBJECTIVE: Leptin is an adipocyte-derived hormone, which is the product of the obese gene and it is thought to play important roles in pubertal development and maintenance of reproductive function in the female. In a study using adult male or female rats, it was found that leptin stimulated the secretion of gonadotropin directly from the pituitary in a dose-related manner. However, there is no study in juvenile female rats before puberty. METHODS: In this study, we cultured pituitary cells from 4-, 6- and 8-week-old female Wistar rats with leptin (0-10(-7)mol/l) and gonadotropin-releasing hormone (GnRH) (0 or 10(-8) mol/l). Basal or GnRH-stimulated secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and their synthesis within cells were determined by radioimmunoassay (RIA). RESULTS: Leptin induced bell-shaped dose--response curves of basal LH and FSH secretion from cultured cells of every age-group of rats studied. The most effective concentration of leptin on the basal secretion of LH and FSH from 6- and 8-week-old cultured pituitary cells was 10(-10) mol/l. This leptin concentration was consistent with circulating physiological serum leptin levels at each age. As for juvenile 4-week-old pituitary cells, the most effective concentration was 10(-11) mol/l which was lower than that of 6- and 8-week-old rats. It was consistent with the circulating serum leptin levels of 4-week-old rats. Also, the synthesis and the GnRH-stimulated secretion of LH and FSH were effectively controlled by leptin at concentrations similar to the serum leptin levels of given ages. CONCLUSIONS: Leptin induced pituitary cells to synthesize and secrete both LH and FSH regardless of the presence or absence of GnRH. The concentration of leptin that induced the greatest synthesis and secretion of gonadotropins from pituitary cells changed around the pubertal period. The most effective leptin concentrations in each experiment were similar to the physiological serum leptin level at each animal age. These results indicate that leptin stimulates gonadotrophs not only in the pubertal and the mature period but also in the juvenile period before puberty. It is also conceivable that leptin may modulate the sensitivity of gonadotrophs until the appearance of GnRH stimulation, and may be the factor that brings about puberty onset.

Identification and partial characterization of a growth hormone-binding protein in rat serum

1990 ◽  
Vol 122 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Morgan Emtner ◽  
Paul Roos
Keyword(s):  
Growth Hormone ◽  
Binding Protein ◽  
Female Rats ◽  
Female Rat ◽  
Rat Serum ◽  
Molecular Weights ◽  
Hormone Binding Protein ◽  
Relative Molecular Weight ◽  
Polyethylene Glycol Precipitation

Abstract A binding protein for growth hormone in serum from female rats has been identified and partially characterized. Serum was incubated with 125I-labelled human GH and fractionated on an agarose HPLC column. Complexes between the binding protein and 125I-hGH were detected as a peak eluted at a volume corresponding to a relative molecular weight of 159000 ± 11000 (N=8). The peak was not seen when the incubation was carried out in the presence of excess unlabelled hGH. The 125I-hGH bound with high affinity (Ka=0.87 ± 0.3 l/nmol;N=3) and the binding was time- and dose-dependent. Bound 125I-hGH was displaced by rat GH and bovine GH, but not by rat prolactin. The protein was not detected in radioreceptor assay by the commonly used polyethylene glycol precipitation technique and was not recognized by a monoclonal antibody raised against lactogenic receptors from female rat liver. Covalent cross-linking of 125I-hGH to serum revealed in SDS electrophoresis two labelled complexes with molecular weights of 62300 ± 3900 and 77600 ± 4100, respectively (N=10).

scholarly journals Plasma dependent and independent accumulation of betaine in male and female rat tissues

2009 ◽  
pp. 403-410 ◽  
Author(s):  
S Slow ◽  
M Lever ◽  
ST Chambers ◽  
PM George
Keyword(s):  
Skeletal Muscle ◽  
Female Rats ◽  
Rat Tissues ◽  
Female Rat ◽  
Male And Female ◽  
Male And Female Rats ◽  
Female Data ◽  
Liver And Kidney ◽  
Gender Specific Differences ◽  
Few Data

Tissue betaine is an intracellular osmolyte that also provides a store of labile methyl groups. Despite these important biological roles, there are few data regarding tissue betaine content. We measured the betaine concentration of plasma and various tissues (brain, heart, lungs, liver, kidney, spleen, intestine, reproductive tissues, skeletal muscle and skin) in male and female rats and assessed whether there were any gender-specific differences in betaine content or distribution and whether there was any relationship between tissue accumulation and plasma levels. Betaine was highest in the liver and kidney with values ranging from 1.6 to 9.5 mmol/l and 2.0 to 5.4 mmol/l, respectively. Plasma betaine concentrations were significantly lower than tissue levels except in the brain (≈ 25 % of plasma) and skeletal muscle (similar to plasma). Regression analysis of the combined male and female data revealed a significant plasma-related accumulation of betaine in the heart, skin and skeletal muscle, while the lung, liver, kidney, spleen, and intestine showed significant plasma-related and plasmaindependent accumulations of betaine. The betaine content of the skin, liver and kidney was not significantly different between males and females, but in plasma and all tissues analyzed it was significantly higher in males (P<0.01).

Effect of serum sex steroids on pituitary LH response to LHRH and LH synthesis

1980 ◽  
Vol 238 (5) ◽  
pp. E458-E462
Author(s):  
L. K. Tang
Keyword(s):  
Luteinizing Hormone ◽  
Sex Difference ◽  
Inhibitory Effect ◽  
Female Rats ◽  
Male Rat ◽  
Female Rat ◽  
Rat Serum ◽  
Lh Release ◽  
Lh Cells ◽  
Stimulatory Factor

To determine the factors responsible for the sex difference in luteinizing hormone (LH) response to luteinizing hormone-releasing hormone (LHRH) observed earlier in pituitary cultures, we examined the effects of serum, 17 beta-estradiol, and testosterone on pituitary LHRH-responsiveness and LH synthesis. Cultures prepared from female rats were maintained in medium supplemented with serums. Dextran-coated charcoal (DCC) adsorption of female rat serum reduced, whereas DCC adsorption of male rat serum increased the pituitary LHRH-responsiveness, indicating the existence of stimulatory factor(s) in female rat serum and inhibitory factor(s) in male rat serum. Readdition of testosterone to DCC female rat serum significantly reduced LH release in response to LHRH (78-32% of the control) without affecting total LH content. Readdition of 17 beta-estradiol to DCC female rat serum significantly increased the LH release in response to LHRH, cellular LH content, and 3H-labeled precursor uptake and incorporation into immunoprecipitable LH. These results indicate that the sex difference in LHRH responsiveness may be attributed to the stimulatory effect of 17 beta-estradiol and the inhibitory effect of testosterone on the LH cells.

OXYDATION DES ANABOLIKUMS 1-METHYL-ANDROST-1-EN-17β-OL-3-ON MIT WASSERSTOFFTRANSFER AUF ÖSTRON

1971 ◽  
Vol 67 (3) ◽  
pp. 517-530 ◽  
Author(s):  
Martin Wenzel
Keyword(s):  
Rat Liver ◽  
Anabolic Steroid ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Liver Slices ◽  
Androgen Effects ◽  
Biochemical Difference

ABSTRACT With the aid of metenolon-17α-T a tritium-transfer to oestrone in rat liver slices was demonstrated. This tritium-transfer from metenolon17α-T to oestrone yielding tritium-labelled oestradiol had a higher efficiency in male than in female rat liver. Correspondingly in the presence of metenolon the relation of oestrone to oestradiol is changed more in male than in female rat liver. Looking for biochemical differences between the anabolic steroid metenolon and testosterone the oxydation at C17 was measured in different organs of the rat using 17α-T-labelled steroids. The highest oxydation rate was found for both steroids in the liver. In the sexual organs of male rats the oxydation rate of testosterone was 50–10 times higher than that of the anabolic steroid. This difference was less in sexual organs of female rats. This result of a greater biochemical difference between both steroids in males than in females leads to the question, whether the dissociation between the anabolic and the androgen effects is higher in males than in females.

GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS:

1968 ◽  
Vol 58 (4) ◽  
pp. 600-612 ◽  
Author(s):  
Robert Boyd ◽  
Donald C. Johnson
Keyword(s):  
Ascorbic Acid ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Female Rat ◽  
Feedback Effects ◽  
Male And Female ◽  
Prostate Weight ◽  
Male And Female Rats ◽  
Males And Females ◽  
Normal Males

ABSTRACT The effects of various doses of testosterone propionate (TP) upon the release of luteinizing hormone (LH or ICSH) from the hypophysis of a gonadectomized male or female rat were compared. Prostate weight in hypophysectomized male parabiotic partners was used to evaluate the quantity of circulating LH. Hypophyseal LH was measured by the ovarian ascorbic acid depletion method. Males castrated when 45 days old secreted significantly more LH and had three times the amount of pituitary LH as ovariectomized females. Administration of 25 μg TP daily reduced the amount of LH in the plasma, and increased the amount in the pituitary gland, in both sexes. Treatment with 50 μg caused a further reduction in plasma LH in males, but not in females, while pituitary levels in both were equal to that of their respective controls. LH fell to the same low level in partners of males or females receiving 100 μg TP. When gonadectomized at 39 days, males and females had the same amount of plasma LH, but males had more stored hormone. Pituitary levels were unchanged from controls following treatment with 12.5, 25 or 50 μg TP daily, but plasma values dropped an equal amount in both sexes with the latter two doses. Androgenized males or females, gonadectomized when 39 days old, were very sensitive to the effects of TP and plasma LH was significantly reduced with 12.5 μg daily. Pituitary LH in androgenized males was higher than that of normal males but was reduced to normal by small amounts of TP. The amount of stored LH in androgenized females was not different from that of normal females and it was unchanged by any dose of TP tested. Results are consistent with the conclusion that the male hypothalamic-hypophyseal axis is at least as sensitive as the female axis to the negative feedback effects of TP. Androgenization increases the sensitivity to TP in both males and females.

Effect of Fetal and Neonatal Hypothyroidism on Glucose Tolerance in Middle-Aged Female Rats

2020 ◽  
Vol 20 ◽  
Author(s):  
Sajad Jeddi ◽  
Saeedeh Khalifi ◽  
Mahboubeh Ghanbari ◽  
Asghar Ghasemi
Keyword(s):  
Glucose Tolerance ◽  
Plasma Glucose ◽  
Female Offspring ◽  
Female Rats ◽  
Control Group ◽  
Female Rat ◽  
Middle Aged ◽  
Intravenous Glucose ◽  
Neonatal Hypothyroidism ◽  
Glucose Levels

Background and objective: The effects of hypothyroidism during pregnancy and lactation on carbohydrate metabolism have been mostly studied in male animals. The aim of this study is therefore to investigate effect of fetal and neonatal hypothyroidism (FH and NH) on the glucose tolerance in middle-aged female rat offspring. Methods: Pregnant female rats were divided into three groups: Rats in the control group consumed tap water, while those in the FH and NH groups consumed 250 mg/L of 6-propyl-2-thiouracil (PTU) in their drinking water during gestation or lactation periods, respectively. After weaning, the female offspring were separated and divided into 3 groups (n=8/group): Control, FH, and NH. Body weight was recorded monthly and intravenous glucose tolerance test (IVGTT) was performed at month 12. Results: Compared to controls, female rats in the FH group had significantly higher plasma glucose levels than controls throughout the IVGTT except at min 60. Values at min 5 of the FH and control group were 196.1±1.9 and 155.3±5.9 mg/dL, respectively (P<0.05). In the NH group, plasma glucose levels were significantly higher only at min 5 (185.7±14.1 vs. 155.3±5.9 mg/dL, P<0.05). Conclusion: Hypothyroidism during fetal or neonatal periods caused glucose intolerance in middle-aged female offspring rats.

Sexual Behavior is Enhanced by Regular, Repeated Mating from Young Adulthood to Middle Age in Female Long-Evans Rats

2020 ◽  
Vol 13 (2) ◽  
pp. 169-177
Author(s):  
Fay A. Guarraci ◽  
Chantal M.F. Gonzalez ◽  
Devon Lucero ◽  
Lourdes K. Davis ◽  
Sarah H. Meerts
Keyword(s):  
Sexual Behavior ◽  
Mating Behavior ◽  
Preference Test ◽  
Sexual History ◽  
Female Rats ◽  
Male Rat ◽  
Female Rat ◽  
Repeated Mating ◽  
First Time ◽  
Mating Tests

Background: Aging is associated neuroendocrine changes in women. Animals can be used to model these changes, as well as changes in reproductive behavior. Objective: The current study was designed to characterize mating behavior across age and assess the effects of age and sexual history on mating behavior. Methods: Sexual motivation was assessed using the partner-preference test, in which a female rat is given the choice to interact with a same-sex conspecific or a sexually-vigorous male rat, with which she can mate. Results: Across repeated mating tests (2-12 months of age), female rats spent more time with the male, displayed more solicitation behaviors, were less likely to leave the male after mounts, but visited both stimulus animals less frequently. Comparing a separate group of age-matched, hormoneyoked female rats mated for the first time at 12 months of age to female rats mated for the first time at 2 months of age showed that the 12 month rats visited both stimulus animals less, were less likely to leave the male after mounts, took longer to return to the male after mounts, and displayed fewer solicitation behaviors than their younger counterparts. Relative to middle-aged female rats once they were sexually experienced, 12 month naïve rats spent less time with the male, were more likely to leave the male after mounts, and displayed fewer solicitation behaviors. Furthermore, 12 month naïve rats failed to discriminate between the stimulus animals, visiting both stimulus animals at the same rate unlike 2 month naïve or 12 month experienced rats. Conclusion: Taken together, these results suggest that aging affects some measures of sexual behavior, but most effects of age can be mitigated by regular, repeated mating.

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