SEX-DEPENDENT PREPUBERTAL GONADOTROPHIN SURGES IN THE RAT

1975 ◽  
Vol 65 (1) ◽  
pp. 91-98 ◽  
Author(s):  
PETER ENEROTH ◽  
JAN-ÅKE GUSTAFSSON ◽  
PAUL SKETT ◽  
ÅKE STENBERG
Keyword(s):  
Sexual Differences ◽  
Female Rats ◽  
Female Rat ◽  
Detection Level ◽  
Male And Female ◽  
Immature Male ◽  
Male And Female Rats ◽  
Second Peak ◽  
Peak Value

SUMMARY The concentrations of LH and FSH were measured by radioimmunoassay in sera from immature male and female rats of various ages. Fairly high levels of FSH were found in both sexes at birth but LH was not detected. FSH peaks appeared in the male at 13 and 19 days of age and in the female at 13 and 17–19 days of age. LH was undetectable in the male before 12 days of age, rose to a peak (440 ± 60 (s.d.) ng/ml) at 13 days of age and fell below the detection level again between 15 and 25 days of age. A further increase then occurred which almost reached adult levels. LH was first detectable in the female rat at 11 days of age with a peak value of 130 ± 35 ng/ml at 12 days. The hormone was undetectable on days 14 and 15, rose to a second peak on day 18 (148 ± 56 ng/ml), and was again absent between 19 and 25 days of age. The concentration rose, as in the male, between days 25 and 28 to a level similar to that of the adult. The results show sexual differences in prepubertal gonadotrophin surges. The LH peak at 12–13 days in both sexes appears to be light-dependent. The FSH peak at this time was affected by light but was not strictly light-dependent.

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

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.

Effects of acute administration of 2-hydroxylated metabolites of oestrogens on LH and prolactin secretion in male and female prepubertal rats

1984 ◽  
Vol 103 (3) ◽  
pp. 317-325
Author(s):  
A. K. Brar ◽  
G. Fink
Keyword(s):  
Plasma Concentration ◽  
Female Rats ◽  
Male Rats ◽  
Male Rat ◽  
Female Rat ◽  
Uterine Weight ◽  
Immature Female ◽  
Male And Female ◽  
Immature Male ◽  
Lh Release

ABSTRACT The effects of catechol oestradiol and catechol oestrone on the release of LH and prolactin were investigated in immature male and female Wistar rats. In male rats both catechol oestradiol and catechol oestrone significantly increased the plasma concentration of LH, and catechol oestradiol but not catechol oestrone significantly increased the plasma concentration of prolactin and decreased the pituitary concentration of LH. The parent oestrogens, oestradiol-17β and oestrone, had no effect on plasma LH concentrations, but both increased significantly the plasma concentration of prolactin, and oestrone but not oestradiol-17β increased the pituitary concentration of LH. In immature female rats, catechol oestradiol inhibited the surge of LH and the increase in uterine weight induced by injecting pregnant mare serum gonadotrophin (PMSG). The injection of oestrone induced an increase in the plasma concentration of LH which was about nine times greater than that produced by oestradiol-17β. There were no significant differences in the effects of these steroids on plasma prolactin concentration. These results (i) confirm that in the immature male rat catechol oestrogens can stimulate LH release and show that catechol oestradiol can increase prolactin release, (ii) show that catechol oestradiol can inhibit the stimulatory effects of PMSG on LH release and uterine weight in the immature female rat, and (iii) demonstrate that oestrone can stimulate LH release in the immature female rat. J. Endocr. (1984) 103, 317-325

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 Absorption, Distribution, Excretion, and Pharmacokinetics ofC-Pyronaridine Tetraphosphate in Male and Female Sprague-Dawley Rats

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Sang Hyun Park ◽  
Kannampalli Pradeep
Keyword(s):  
Clinical Trials ◽  
Small Intestine ◽  
Oral Administration ◽  
Female Rats ◽  
Sprague Dawley ◽  
Male And Female ◽  
Phase Ii Clinical Trials ◽  
Male And Female Rats ◽  
Sprague Dawley Rats ◽  
Peak Value

The main objective of this investigation was to determine the absorption, distribution, excretion, and pharmacokinetics of the antimalarial drug pyronaridine tetraphosphate (PNDP) in Sprague-Dawley rats. Following oral administration of a single dose (10 mg/Kg) ofC-PNDP, it was observed that the drug was readily absorbed from the small intestine within 1 hour following oral administration and was widely distributed in most of the tissues investigated as determined from the observed radioactivity in the tissues. The peak value of the drug in the blood was reached at around 8 hours postadministration, and radioactivity was detected in most of the tissues from 4 hours onwards.C-PNDP showed a poor permeability across the blood-brain barrier, and the absorption, distribution, and excretion ofC-PNDP were found to be gender-independent as both male and female rats showed a similar pattern of radioactivity. Excretion of the drug was predominantly through the urine with a peak excretion post 24 hours of administration. A small amount of the drug was also excreted in the feces and also in the breath. It was found that theCmax, AUC (0-inf), andTmaxvalues were similar to those observed in the Phase II clinical trials of pyronaridine/artesunate (Pyramax) conducted in Uganda.

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.

CONTRASTING EFFECTS OF SOME STEROIDAL HORMONES UPON L-CYSTINE-AMINOPEPTIDASE ACTIVITY IN THE HYPOTHALAMUS OF IMMATURE MALE AND FEMALE RATS

1972 ◽  
Vol 68 (3_Suppl) ◽  
pp. S59
Author(s):  
H. Kuhl ◽  
W. Bickel ◽  
J. Enenkel ◽  
G. Hauptmann ◽  
P. Chandra ◽  
...  
Keyword(s):  
Female Rats ◽  
Aminopeptidase Activity ◽  
Male And Female ◽  
Immature Male ◽  
Male And Female Rats ◽  
Steroidal Hormones
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