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

scholarly journals Increased bioactivation of dihaloalkanes in rat liver due to induction of class Theta glutathione S-transferase T1-1

1998 ◽  
Vol 335 (3) ◽  
pp. 619-630 ◽  
Author(s):  
Philip J. SHERRATT ◽  
Margaret M. MANSON ◽  
Anne M. THOMSON ◽  
Erna A. M. HISSINK ◽  
Gordon E. NEAL ◽  
...  
Keyword(s):  
Western Blotting ◽  
Rat Liver ◽  
Female Rats ◽  
Male Rats ◽  
Male Rat ◽  
Female Rat ◽  
Glutathione S Transferase ◽  
Chemopreventive Agents ◽  
Cytoplasmic Staining ◽  
Potent Inducer

A characteristic feature of the class Theta glutathione S-transferase (GST) T1-1 is its ability to activate dichloromethane and dibromoethane by catalysing the formation of mutagenic conjugates. The level of the GSTT1 subunit within tissues is an important determinant of susceptibility to the carcinogenic effects of these dihaloalkanes. In the present study it is demonstrated that hepatic GST activity towards these compounds can be elevated significantly in female and male Fischer-344 rats by feeding these animals on diets supplemented with cancer chemopreventive agents. Immunoblotting experiments showed that increased activity towards the dihaloalkanes is associated with elevated levels of the GSTT1 subunit in rat liver. Sex-specific effects were observed in the induction of GSTT1 protein. Amongst the chemopreventive agents tested, indole-3-carbinol proved to be the most potent inducer of hepatic GSTT1 in male rats (6.2-fold), whereas coumarin was the most potent inducer of this subunit in the livers of female rats (3.5-fold). Phenobarbital showed significant induction of GSTT1 only in male rat liver and had little effect in female rat liver. Western blotting showed that class Alpha, Mu and Pi GST subunits are not co-ordinately induced with GSTT1, indicating that the expression of GSTT1 is determined, at least in part, by mechanisms distinct from those that regulate levels of other transferases. The increase in amount of hepatic GSTT1 protein was also reflected by an increase in the steady-state level of mRNA in response to treatment with chemopreventive agents and model inducers. Immunohistochemical detection of GSTT1 in rat liver supported the Western blotting data, but showed, in addition to cytoplasmic staining, significant nuclear localization of the enzyme in hepatocytes from some treated animals, including those fed on an oltipraz-containing diet. Significantly, the hepatic level of cytochrome P-450 2E1, an enzyme which offers a detoxification pathway for dihaloalkanes, was unchanged by the various inducing agents studied. It is concluded that the induction of GSTT1 by dietary components and its localization within cells are important factors that should be considered when assessing the risk dihaloalkanes pose to human health.

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 Functional implications of the sex differences in transporter abundance along the rat nephron: modeling and analysis

2019 ◽  
Vol 317 (6) ◽  
pp. F1462-F1474 ◽  
Author(s):  
Rui Hu ◽  
Alicia A. McDonough ◽  
Anita T. Layton
Keyword(s):  
Sex Differences ◽  
Computational Models ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Distal Nephron ◽  
Male And Female ◽  
Modeling And Analysis ◽  
Functional Implications ◽  
Rat Kidneys

The goal of the present study was to investigate the functional implications of sexual dimorphism in the pattern of transporters along the rodent nephron as reported by Veiras et al. ( J Am Soc Nephrol 28: 3504–3517, 2017). To do so, we developed sex-specific computational models of water and solute transport along the superficial nephrons from male and female rat kidneys. The models account for the sex differences in the abundance of apical and basolateral transporters, single nephron glomerular filtration rate, and tubular dimensions. Model simulations predict that ~70% and 60% of filtered Na+ is reabsorbed by the proximal tubule of male and female rat kidneys, respectively. The lower fractional Na+ reabsorption in female kidneys is due primarily to their smaller transport area, lower Na+/H+ exchanger activity, and lower claudin-2 abundance, culminating in significantly larger fractional delivery of water and Na+ to the downstream nephron segments in female kidneys. Conversely, the female distal nephron exhibits a higher abundance of key Na+ transporters, including Na+-K+-Cl− cotransporters, Na+-Cl− cotransporters, and epithelial Na+ channels. The higher abundance of transporters accounts for the enhanced water and Na+ transport along the female, relative to male, distal nephron, resulting in similar urine excretion between the sexes. Consequently, in response to a saline load, the Na+ load delivered distally is greater in female rats than male rats, overwhelming transport capacity and resulting in higher natriuresis in female rats.

BIOLOGICAL EFFECTS OF HUMAN URINARY FOLLICLE STIMULATING HORMONE

1970 ◽  
Vol 63 (3) ◽  
pp. 454-475 ◽  
Author(s):  
P. Petrusz ◽  
C. Robyn ◽  
E. Diczfalusy
Keyword(s):  
Biological Effects ◽  
Follicle Stimulating Hormone ◽  
Interstitial Cells ◽  
Female Rats ◽  
Male Rats ◽  
Weight Increase ◽  
Uterine Weight ◽  
Immature Female ◽  
Ovarian Weight ◽  
Female Mice

ABSTRACT The biological effects of human follicle stimulating hormone (FSH) preparations were studied in intact immature female mice and in hypophysectomized immature female and male rats, following the complete neutralization of the luteinizing hormone (LH) content of human urinary menopausal gonadotrophin (HMG) preparations having – prior to neutralization – FSH:LH ratios ranging between 1.0 and 500.0. Neutralization of LH was achieved by the addition of rabbit anti-human chorionic gonadotrophin (HCG) sera of known anti-LH potency. The amount of anti-LH employed was 1.5 to 730 times more than that required for 100% neutralization. In intact immature female mice, such »LH-free« FSH preparations induced an increased ovarian weight, follicle stimulation, as well as a uterine weight increase. In immature hypophysectomized female rats, »LH-free« FSH preparations induced ovarian weight increase, growth and maturation of the Graafian follicles without repair of the deficient interstitial cells and without any signs of luteinization. These ovarian changes were associated with an increase in uterine weight and with vaginal cornification. In view of these data, it is concluded that human urinary FSH per se is capable of inducing oestrogen synthesis in hypophysectomized female rats. In immature hypophysectomized male rats, »LH-free« FSH preparations induced testicular enlargement without any stimulation of the testicular interstitial cells and without any growth of the ventral prostate and seminal vesicles. The same effects were obtained following a prolonged administration (3 weeks); spermiogenesis was stimulated, but no mature spermatozoa were found.

EFFECTS OF NALOXONE ON LUTEINIZING HORMONE AND PROLACTIN IN SERUM OF RATS

1980 ◽  
Vol 85 (2) ◽  
pp. 307-315 ◽  
Author(s):  
M. S. BLANK ◽  
A. E. PANERAI ◽  
H. G. FRIESEN
Keyword(s):  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Serum Prolactin ◽  
Immature Female ◽  
Subcutaneous Injections ◽  
Serum Lh ◽  
Opiate Peptides ◽  
Lh Release ◽  
Lh Secretion

The effects of subcutaneous injections of the opiate antagonist naloxone on the tonic and phasic secretion of prolactin and LH were studied in rats. During development, resting levels of prolactin in serum were decreased by naloxone (2·5 mg/kg body wt) on days 24,45 and 50 in female rats and on days 28,45 and 50 in male rats. In the adult, naloxone (2·5 mg/kg body wt) decreased basal levels of serum prolactin in male rats and levels during oestrus in female rats. In 25-day-old female rats, serum LH rose from resting levels within 7·5 min of naloxone administration (2·5 mg/kg body wt) and returned to pretreatment levels by 30 min, while prolactin fell by 7·5 min and remained low for as long as 60 min after treatment. Furthermore, a tenfold lower dose of naloxone (0·25 mg/kg body wt) did not raise basal levels of serum LH but still decreased resting levels of serum prolactin in immature female rats (24 days old). The effect of naloxone (2·5 mg/kg body wt) on phasic LH release was studied in 29-day-old immature female rats primed on day 27 with pregnant mare serum gonadotrophin (PMSG). In these PMSG-treated rats the onset of the prolactin surge was blunted by naloxone while it had no effect on phasic LH release. Naloxone (5 mg/kg body wt) also induced a rise in levels of serum LH in ovariectomized rats and, if administered with morphine, it reversed the short-term inhibition of LH secretion caused by morphine. However, naloxone was ineffective after pretreatment with oestradiol benzoate. These findings suggest that the responses of serum LH and prolactin to naloxone were dissociated and that oestrogens and opiate peptides may have interacted to regulate secretion of LH.

scholarly journals Effect of Ashwagandharista (Withania somnifera) on the kidney functions of male and female rats

2019 ◽  
Vol 8 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Tasmina Rahman ◽  
Md Rakib Hasan ◽  
MSK Choudhuri
Keyword(s):  
Uric Acid ◽  
Female Rats ◽  
Male Rats ◽  
Toxicity Tests ◽  
Male Rat ◽  
Serum Urea ◽  
Urea Level ◽  
Male And Female ◽  
Kidney Functions ◽  
Medium Dose

The key objective of this present study was to analyze the effect(s) of Ashwagandharishta on the kidney functions of both male and female Albino rats. Chronic toxicity tests were also done. Following treatments the rats were observed for 51 days to know the effects of Ashwagandharishta on kidney functions considering 3 parameters such as serum urea, creatinine and uric acid. Our results failed to exhibit a significant increase in serum urea level at low dose (P<0.01), medium dose (P<0.05) and at high dose (P<0.001) in male rat groups; but with female rat groups our results showed significant increase in serum urea level at three dose levels. Regarding serum creatinine level male rats and female rats showed a trend of increase in level at different dose but effects were insignificant except medium dose in male rats (P<0.05). Regarding serum uric acid level our results failed to show a significant increase irrespective of dose. Jahangirnagar University J. Biol. Sci. 8(1): 1-7, 2019 (June)

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.

EXPERIMENTAL EVALUATION OF DIURETICS IN THE RAT

1956 ◽  
Vol 34 (1) ◽  
pp. 903-911
Author(s):  
J. D. McColl ◽  
J. M. Parker ◽  
J. K.W. Ferguson
Keyword(s):  
Carbonic Anhydrase ◽  
Dose Range ◽  
Carbonic Anhydrase Inhibitor ◽  
Female Rats ◽  
Male Rats ◽  
Male Rat ◽  
High Dose ◽  
Female Rat ◽  
Inhibitor Type ◽  
Almost All

The diuretic response of the male and the female rat to aminophylline has been studied when these animals were pretreated with various concentrations of sodium chloride solution. A linear log dose – response curve was obtained over the dose range employed with male rats pretreated with 0.45% and 2% saline. Male rats exhibited a diuresis with 4% saline which was not increased by aminophylline. Female rats showed diuresis but the responses were more variable for almost all combinations of electrolyte load and xanthine dose. When they were pretreated with 0.45% and 2% saline, aminophylline caused some additional production of urine but this was much less regular than that observed with males. The variation in response to aminophylline after 4% saline was very marked but the trend suggested that the xanthine had a diuretic effect at the high dose. The diuretic responses to a xanthine, a mercurial, and a carbonic anhydrase inhibitor type of diuretic were compared in the male rat. Peak responses were smallest after the mercurial diuretic and greatest with the carbonic anhydrase inhibitor.

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.

Neuropharmacological analysis of the control of LH secretion in gonadectomized male and female rats: altered hypothalamic responses to inhibitory neurotransmitters in long-term castrated rats

1988 ◽  
Vol 119 (1) ◽  
pp. 15-21 ◽  
Author(s):  
O. F. X. Almeida ◽  
K. E. Nikolarakis ◽  
A. Herz
Keyword(s):  
Opioid Receptor ◽  
Female Rats ◽  
Male Rats ◽  
Dopaminergic Agonists ◽  
Male And Female ◽  
Opioid Agonists ◽  
Male And Female Rats ◽  
Lh Release ◽  
Lh Secretion

ABSTRACT The control of LHRH and LH by neurotransmitters and neuromodulators such as the endogenous opioid peptides is essentially the same in intact adult male and female rats: adrenergic and dopaminergic agonists stimulate LH release and opioid agonists inhibit it. Several weeks after gonadectomy, however, the contribution of the endogenous ligands of adrenergic, dopaminergic and opioidergic receptors to the control of LHRH is altered. A detailed pharmacological analysis in long-term ovariectomized females confirmed previous reports that adrenergic and dopaminergic agonists still enhance secretion of LHRH and LH and opioid receptor agonists still suppress it. A similar investigation in long-term castrated males also confirmed previous reports that opioid agonists fail to block LH secretion. In addition, we have found that while adrenergic and dopaminergic agonists cause increases in serum concentrations of LH, adrenoreceptor and dopamine receptor antagonists do not inhibit LH release in long-term castrates. Furthermore, the opioid antagonist naloxone does not raise serum LH levels in either sex after long-term gonadectomy. These observations therefore imply reduced opioidergic, dopaminergic and adrenergic transmission, in relation to LHRH release, after longterm castration. In addition, opioid receptor activity (assessed by responsiveness to an opioid receptor agonist) of female rats is maintained, whereas that of male rats is lost, after long-term gonadectomy. J. Endocr. (1988) 119, 15–21

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