Sex differences result in increased morbidity from hyponatremia in female rats

1989 ◽  
Vol 256 (4) ◽  
pp. R880-R885 ◽  
Author(s):  
C. L. Fraser ◽  
J. Kucharczyk ◽  
A. I. Arieff ◽  
C. Rollin ◽  
P. Sarnacki ◽  
...  
Keyword(s):  
Arginine Vasopressin ◽  
High Energy ◽  
Female Rats ◽  
Resonance Spectroscopy ◽  
Female Rat ◽  
High Energy Phosphate ◽  
Male And Female ◽  
Sodium Uptake ◽  
Male And Female Rats ◽  
The Brain

The development of symptomatic hyponatremia in otherwise healthy young women can result in death or permanent brain damage. The reasons for the increased female susceptibility to complications from hyponatremia are, however, unclear. To determine whether mechanisms that normally defend the brain against damage from hyponatremia are less effective in females than males, we studied both sodium transport in the brains of hyponatremic male and female rats and the effects of parenteral arginine vasopressin on brain high-energy phosphate metabolism and intracellular pH. Basal sodium uptake in synaptosomes prepared from whole brain of females (2.20 nmol/mg protein) and males (2.98 nmol/mg protein) was not statistically different. In contrast, veratridine-stimulated sodium uptake in female brain was 8.20 nmol/mg protein, which was 86% greater (P less than 0.001) than the 6.12 nmol/mg protein observed for male brain. Additionally, sodium uptake between 5 and 60 s was significantly (P less than 0.001) greater in females than males. These data suggest that the Na+-K+-adenosinetriphosphatase (ATPase) pump function in female rat brain synaptosomes is less effective than in males. To determine whether arginine vasopressin, a peptide hormone that promotes water retention by the kidney, had any effects on cerebral energy metabolism, we performed phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) studies on the brain of normonatremic young adult male and female rats subjected to high (20 IU) peripheral doses of arginine vasopressin.We found decreased high-energy phosphate generation, elevated inorganic phosphate, and intracellular acidosis after arginine vasopressin administration in females but not males.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

scholarly journals Glutathione Conjugates of Ochratoxin a as Biomarkers of Exposure / Glutationski Konjugati Okratoksina A Kao Biomarkeri Izloženosti

2012 ◽  
Vol 63 (4) ◽  
pp. 417-427 ◽  
Author(s):  
Mariana Tozlovanu ◽  
Delphine Canadas ◽  
Annie Pfohl-Leszkowicz ◽  
Christine Frenette ◽  
Robert J. Paugh ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Rat Kidney ◽  
Female Rats ◽  
Amide Bond ◽  
Male Rats ◽  
Dark Agouti ◽  
Female Rat ◽  
Male And Female ◽  
Male And Female Rats ◽  
Liver And Kidney

AbstractIn the present study the photoreactivity of the fungal carcinogen ochratoxin A (OTA) has been utilised to generate authentic samples of reduced glutathione (GSH) and N-acetylcysteine (NAC) conjugates of the parent toxin. These conjugates, along with the nontoxic OTα, which is generated through hydrolysis of the amide bond of OTA by carboxypeptidase A, were utilised as biomarkers to study the metabolism of OTA in the liver and kidney of male and female Dark Agouti rats. Male rats are more susceptible than female rats to OTA carcinogenesis with the kidney being the target organ. Our studies show that the distribution of OTA in male and female rat kidney is not significantly different. However, the extent of OTA metabolism was greater in male than female rats. Much higher levels of OTα were detected in the liver compared to the kidney, and formation of OTα is a detoxification pathway for OTA. These findings suggest that differences in metabolism between male and female rats could provide an explanation for the higher sensitivity of male rats to OTA toxicity

Differential energetic response of brain vs. skeletal muscle upon glycemic variations in healthy humans

2008 ◽  
Vol 294 (1) ◽  
pp. R12-R16 ◽  
Author(s):  
Kerstin M. Oltmanns ◽  
Uwe H. Melchert ◽  
Harald G. Scholand-Engler ◽  
Maria C. Howitz ◽  
Bernd Schultes ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Underlying Mechanism ◽  
High Energy ◽  
Resonance Spectroscopy ◽  
Energy Status ◽  
High Energy Phosphate ◽  
Available Energy ◽  
Healthy Humans ◽  
High Energy Phosphate Metabolism ◽  
The Brain

The brain regulates all metabolic processes within the organism, and therefore, its energy supply is preserved even during fasting. However, the underlying mechanism is unknown. Here, it is shown, using 31P-magnetic resonance spectroscopy that during short periods of hypoglycemia and hyperglycemia, the brain can rapidly increase its high-energy phosphate content, whereas there is no change in skeletal muscle. We investigated the key metabolites of high-energy phosphate metabolism as rapidly available energy stores by 31P MRS in brain and skeletal muscle of 17 healthy men. Measurements were performed at baseline and during dextrose or insulin-induced hyperglycemia and hypoglycemia. During hyperglycemia, phosphocreatine (PCr) concentrations increased significantly in the brain ( P = 0.013), while there was a similar trend in the hypopglycemic condition ( P = 0.055). Skeletal muscle content remained constant in both conditions ( P > 0.1). ANOVA analyses comparing changes from baseline to the respective glycemic plateau in brain (up to +15%) vs. muscle (up to −4%) revealed clear divergent effects in both conditions ( P < 0.05). These effects were reflected by PCr/Pi ratio ( P < 0.05). Total ATP concentrations revealed the observed divergency only during hyperglycemia ( P = 0.018). These data suggest that the brain, in contrast to peripheral organs, can activate some specific mechanisms to modulate its energy status during variations in glucose supply. A disturbance of these mechanisms may have far-reaching implications for metabolic dysregulation associated with obesity or diabetes mellitus.

scholarly journals Intrasplenic Transplantation of Isolated Adult Rat Hepatocytes

2011 ◽  
Vol 40 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Meena R. Sharma ◽  
Wojciech Dworakowski ◽  
Bernard H. Shapiro
Keyword(s):  
Cytochrome P450 ◽  
Adult Male ◽  
Total Concentration ◽  
Rat Hepatocytes ◽  
Female Rats ◽  
Female Rat ◽  
Male And Female ◽  
Sexual Dimorphisms ◽  
Male And Female Rats ◽  
Male Specific

Adult male and female rat hepatocytes were individually transplanted into the spleens of adult male and female rats. The recipients were euthanized at either eight, sixteen, thirty, or forty-five weeks following transplantation, at which time hepatic and splenic levels of liver-specific rat albumin mRNA as well as sex-dependent transcript levels of CYP2C11, -2C12, -2C7, -2A1, and -3A2—which accounts for > 60% of the total concentration of hepatic constituent cytochrome P450—were determined. Whereas the pre-infused hepatocytes expressed their expected cytochrome P450 sexual dimorphisms (female-specific CYP2C12, male-specific CYP3A2, and female-predominant CYP2A1), their post-transplantational competence now reflected the sexual dimorphisms of the recipient (as observed in the host’s liver), which supports the concept that the sex-dependent growth hormone circulating profiles are the determinants regulating the expression levels of hepatic cytochrome P450. Also expressed at normal concentrations in the pre-infused hepatocytes, male-specific CYP2C11 and female-predominant CYP2C7 were inexplicably undetectable in the spleens of both recipient males and females, regardless of the sex of the donor hepatocytes, almost one year after transplantation.

Effect of long-term undernutrition on male and female rat diaphragm contractility, fatigue, and fiber types

1994 ◽  
Vol 76 (4) ◽  
pp. 1540-1547 ◽  
Author(s):  
D. J. Prezant ◽  
B. Richner ◽  
T. K. Aldrich ◽  
D. E. Valentine ◽  
E. I. Gentry ◽  
...  
Keyword(s):  
Weight Gain ◽  
Fatigue Resistance ◽  
Female Rats ◽  
Fiber Types ◽  
Female Rat ◽  
Male And Female ◽  
Male And Female Rats ◽  
Males And Females ◽  
Diaphragm Atrophy

The effects of long-term undernutrition (10 wk) on diaphragm contractility, fatigue, and fiber type proportions were studied in male and female rats. Contractility and fatigue resistance indexes were measured in an in vitro diaphragm costal strip preparation by using direct stimulation at 37 degrees C. Undernutrition allowed for continued growth in males and females but with substantial reductions in weight gain. Relative to control rats of the same sex, final weights were significantly lower in undernourished males (74 +/- 3%) than females (90 +/- 5%), but weight gain was not significantly different between undernourished males (58 +/- 5%) and females (60 +/- 3%). Only in males did undernutrition significantly reduce costal diaphragm weight (to 77 +/- 5% of control). Diaphragm forces, normalized for cross-sectional area, were not significantly different from male or female control values. Fatigue resistance indexes (fatigue/baseline force) were increased at all stimulation frequencies in undernourished males but not in undernourished females. Costal diaphragm atrophy, involving types I and II fibers, occurred in undernourished males but not in undernourished females. In conclusion, despite long-term undernutrition reducing weight gain to similar levels in males and females (relative to control), there was excellent preservation of diaphragm weight, function, and structure in females but, although diaphragm atrophy occurred, there was preserved contractility and increased fatigue resistance in males.

CELLULAR LOCALIZATION OF A PROLACTIN-LIKE ANTIGEN IN THE RAT BRAIN

1979 ◽  
Vol 83 (2) ◽  
pp. 261-NP ◽  
Author(s):  
G. TOUBEAU ◽  
J. DESCLIN ◽  
M. PARMENTIER ◽  
J. L. PASTEELS
Keyword(s):  
Rat Brain ◽  
Cellular Localization ◽  
Female Rats ◽  
Nerve Fibres ◽  
Male And Female ◽  
Immunoreactive Material ◽  
Paraventricular Nuclei ◽  
Male And Female Rats ◽  
The Brain

The distribution of immunoreactive neurones and fibres was studied in rat brain using an antiserum to rat prolactin. Neurones containing the immunoreactive material were localized in the arcuate, ventromedial, premamillary, supraoptic and paraventricular nuclei of the hypothalamus. Immunoreactive nerve fibres were widely distributed within the brain. No differences were observed in labelling between male and female rats, or as a consequence of hypophysectomy.

Age Changes in Secretory Function of Male and Female Rat Parotid Glands in Response to Methoxamine and Pilocarpine

1988 ◽  
Vol 67 (3) ◽  
pp. 565-573 ◽  
Author(s):  
A. Inanaga ◽  
T. Habu ◽  
E. Tanaka ◽  
T. Taniguch ◽  
T. Nishiura ◽  
...  
Keyword(s):  
Amino Acid ◽  
Inorganic Phosphate ◽  
Amylase Activity ◽  
Salivary Flow ◽  
Female Rats ◽  
Female Rat ◽  
Parotid Glands ◽  
Male And Female ◽  
Male And Female Rats ◽  
Age And Sex

Saliva secreted in response to methoxamine and pilocarpine was collected from the cannulated ducts of both parotid glands of male and female rats at weekly age intervals from three to 10 weeks, and at 3.5, 8, and 15 months of age. It was analyzed for the concentrations of protein, potassium, calcium, inorganic phosphate, and for amylase activity. The types of protein were determined electrophoretically, and an amino acid analysis of the total protein was also carried out. The wet weights of the glands increased substantially up to eight weeks of age, then reached almost plateau values, and finally tended to decrease at 15 months of age in both sexes. The salivary volumes secreted in response to methoxamine and pilocarpine were positively correlated with the parotid gland weights in both sexes. The concentrations of protein, potassium, and inorganic phosphate were inversely related to the salivary flow rates only at relatively low rates of flow. The amylase activity was positively correlated with the concentration of protein, independent of the nature of the stimulus, age, and sex. With methoxamine as a stimulus, the amylase activity was positively correlated with the concentration of calcium, independent of age and sex. The types of protein and amino acid concentrations were independent of the nature of the stimulus, age, and sex up to 15 months of age. However, in parotid saliva of several rats at 8 and 15 months of age, unusual proteins were observed electrophoretically, independent of the nature of the stimulus and sex.

scholarly journals SEX DIFFERENCES IN μ-OPIOID REGULATION OF COERULEAR-CORTICAL TRANSMISSION

2020 ◽  
Author(s):  
Herminio M Guajardo ◽  
Rita J Valentino
Keyword(s):  
Sex Differences ◽  
Prefrontal Cortex ◽  
Cognitive Flexibility ◽  
Field Potential ◽  
Endogenous Opioids ◽  
Female Rats ◽  
Cognitive Responses ◽  
Female Rat ◽  
Male And Female ◽  
Male And Female Rats

ABSTRACTStress-induced activation of locus coeruleus (LC)-norepinephrine (NE) projections to the prefrontal cortex is thought to promote cognitive responses to stressors. LC activation by stressors is modulated by endogenous opioids that serve to restrain LC activation and to facilitate a return to baseline activity upon stress termination. Sex differences in this opioid influence could be a basis for sex differences in stress vulnerability. Consistent with this, we recently demonstrated that μ-opioid receptor (MOR) expression is decreased in the female rat LC compared to the male LC and this was associated with sexually distinct consequences of activating MOR in the LC on cognitive flexibility. Given that the LC-NE system affects cognitive flexibility through its projections to the medial prefrontal cortex (mPFC), the present study quantified and compared the effects of LC-MOR activation on mPFC neural activity in male and female rats. Local field potential (LFPs) were recorded from the mPFC of freely behaving male and female rats before and following local LC microinjection of the MOR agonist, DAMGO or vehicle. Intra-LC DAMGO altered the LFP power spectrum selectively in male, but not female rats, resulting in a time-dependent increase in the power in delta and alpha frequency bands. LC microinfusion of ACSF had no effect in either sex. Together, the results are consistent with previous evidence for decreased MOR function in the female rat LC and demonstrate that this translates to a diminished effect on cortical activity that can account for sex differences in cognitive consequences. Decreased LC-MOR function in females could contribute to greater stress-induced activation of the LC, and increased vulnerability of females to hyperarousal symptoms of stress-related neuropsychiatric pathologies.

Change from beta- to alpha-adrenergic glycogenolysis induced by corticosteroids in female rat liver

1997 ◽  
Vol 273 (1) ◽  
pp. R153-R160
Author(s):  
M. Moriyama ◽  
Y. Nakanishi ◽  
S. Tsuyama ◽  
Y. Kannan ◽  
M. Ohta ◽  
...  
Keyword(s):  
Glucose Production ◽  
Plasma Corticosterone ◽  
Mature Female ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Circadian Variations ◽  
Male And Female ◽  
Male And Female Rats ◽  
The Difference

The conversion of beta- to alpha-adrenergic glycogenolysis by corticosteroids was studied in perfused livers of mature female rats. Isoproterenol stimulated glucose production more effectively in female rats than in male rats, but the difference in its stimulatory effect disappeared in adrenalectomized (ADX) rats, whereas it remained in adrenodemedulated rats. When ADX female rats were treated with dexamethasone sulfate, alpha-responses increased and beta-responses decreased, depending on the concentration of dexamethasone sulfate. The treatment of female rats with 1.5 mg/kg dexamethasone sulfate changed the levels of the alpha- and beta-responses to those observed in male rats, and the changes were associated with changes in the number of receptors. Although periodicity of changes in plasma corticosterone levels was observed in both male and female rats, the extent of circadian variations was significantly lower in female rats during the estrous cycle than in male rats. The variations in plasma corticosterone levels and in both alpha- and beta-responses after ovariectomy approached those in male rats. The results suggest that the level of plasma corticosterone might play an important role in the regulation of the relative levels of alpha- and beta-adrenergic responses in female rats.

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