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

EFFECT OF SMALL DOSES OF OESTRADIOL BENZOATE ON PITUITARY PRODUCTION AND RELEASE OF I. C. S. H. IN GONADECTOMIZED MALE AND FEMALE RATS

1962 ◽  
Vol 39 (2) ◽  
pp. 245-252 ◽  
Author(s):  
E. Gans ◽  
G. P. van Rees
Keyword(s):  
Term Treatment ◽  
Female Rats ◽  
Male Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Long Term Treatment ◽  
Oestradiol Benzoate ◽  
Small Doses ◽  
Higher Doses

ABSTRACT The influence on the I. C. S. H.-content of the pituitary gland and the blood serum of long-term treatment of gonadectomized male and female rats with several low doses of oestradiol benzoate was investigated. It was found that only in females treatment with 0.1 and 0.2 μg of oestradiol benzoate daily results in an increase of the pituitary I. C. S. H.-content, whereas in the serum content a (non-significant) decrease was observed. In male rats the pituitary I. C. S. H.-content was not influenced by treatment with these doses, but the serum content decreased. Higher doses of oestradiol (0.5 and 2.0 μg daily) caused, both in males and in females, a decrease of the I. C. S. H.-content in the hypophysis as well as in the serum. It is assumed that oestrogen, if chronically administered, exerts two different actions on pituitary I. C. S. H.: it depresses the production of I. C. S. H. and inhibits the release. In females, these two effects have different threshold levels, that for the release being the lower one. In males the threshold for the inhibition of production has to be lower.

Effects of long- and short-term gonadectomy on the hypothalamo-hypophysial (LH-releasing hormone–LH) system in oestrogen-treated male and female rats

1986 ◽  
Vol 110 (2) ◽  
pp. 367-373 ◽  
Author(s):  
N. G. Weiland ◽  
C. A. Barraclough ◽  
K. J. Catt
Keyword(s):  
Female Rats ◽  
Short Term ◽  
Male And Female ◽  
Oestradiol Treatment ◽  
Male And Female Rats ◽  
Serum Lh ◽  
Lh Release ◽  
Males And Females ◽  
Lh Releasing Hormone

ABSTRACT Considerable differences have previously been found in the hypothalamo-hypophysial responsiveness to oestrogen, depending upon the time between gonad removal and exposure to oestrogen. In the present study a detailed analysis was made of some of the differences which may exist in pituitary LH-releasing hormone (LHRH) receptors and the amount of LH released in response to electrochemical depolarization of the medial preoptic area after 2 or 7 days of oestradiol treatment of long- and short-term gonadectomized male and female rats. The pituitary glands of long-term gonadectomized males and females secreted more LH in response to two pulse injections of LHRH than did short-term gonadectomized rats. The amount of LH released on day 2, however, was equivalent to that secreted after 7 days of oestradiol treatment. Moreover, long-term gonadectomized males and females had equivalent LHRH receptor concentrations, which were greater than those of short-term gonadectomized animals. Peak serum LH concentrations observed after preoptic stimulation were equivalent in short- and long-term castrated rats after 2 days of oestrogen exposure. Serum LH concentrations following preoptic stimulation in short-term gonadectomized males and females were significantly greater on day 7 than on day 2 of oestradiol treatment, whereas in long-term gonadectomized animals the stimulated release of LH was equivalent both in magnitude and time of peak release on both days. These studies demonstrate that the differential effects of oestradiol on LH release on day 2 (no negative feedback) compared with day 7 (both negative and positive feedback exist) are not due to differences in the ability of the pituitary gland to release LH in response to LHRH, nor in the releasable pools of hypothalamic LHRH in long-term gonadectomized rats. Rather, they seem to be due to a refractoriness in some unidentified central nervous process which regulates tonic LH release in gonadectomized rats. J. Endocr. (1986) 110, 367–373

Distribution of nickel in body fluids and organs of rats chronically exposed to nickel sulphate

1995 ◽  
Vol 14 (12) ◽  
pp. 955-958 ◽  
Author(s):  
J. Severa ◽  
A. Vyskocil ◽  
Z. Fiala ◽  
M. Cizkova
Keyword(s):  
Blood Serum ◽  
Whole Blood ◽  
Absorbed Dose ◽  
Body Fluids ◽  
Female Rats ◽  
Male Rats ◽  
Nickel Sulphate ◽  
Male And Female ◽  
Male And Female Rats

1 Male and female rats were given 100 mg Ni L-1 (as nick el sulphate) in drinking water for 6 months. 2 The feeding of nickel was associated with an increased concentration of nickel in body fluids and organs. The highest concentrations of nickel were found in the liver of both male and female rats. In male rats nickel levels decreased in the order: liver > kidney = whole blood = serum > testes > urine. In female rats the decreasing order was similar: liver > kidney = whole blood = serum = plasma > urine > ovaries. 3 No significant differences were found between nickel concentrations in organs (except ovaries), blood and urine of rats exposed for 3 months and those exposed for 6 months indicating the reaching of a steady state of nickel in the rat during long-term exposure. 4 The urinary excretion of the orally administered nickel was only 2% of absorbed dose (supposing 1% Ni absorp tion).

INDUCTION OF GOITRE BY PTU OR KClO4 IN MALE AND FEMALE RATS. EFFECT OF GONADECTOMY

1973 ◽  
Vol 74 (1) ◽  
pp. 88-104 ◽  
Author(s):  
T. Jolín ◽  
M. J. Tarin ◽  
M. D. Garcia
Keyword(s):  
Iodine Content ◽  
High Plasma ◽  
Disc Electrophoresis ◽  
Female Rats ◽  
Male Rats ◽  
Adult Rats ◽  
Male And Female ◽  
Glucose Levels ◽  
Male And Female Rats ◽  
Tsh Levels

ABSTRACT Male and female rats of varying ages were placad on a low iodine diet (LID) plus KClO4 or 6-propyl-2-thiouracil (PTU) or on the same diet supplemented with I (control rats). Goitrogenesis was also induced with LID plus PTU in gonadectomized animals of both sexes. The weight of the control and goitrogen treated animals, and the weight and iodine content of their thyroids were determined, as well as the plasma PBI, TSH, insulin and glucose levels. The pituitary GH-like protein content was assessed by disc electrophoresis on polyacrylamide gels. If goitrogenesis was induced in young rats of both sexes starting with rats of the same age, body weight (B.W.) and pituitary growth hormone (GH) content, it was found that both the males and females developed goitres of the same size. On the contrary, when goitrogenesis was induced in adult animals, it was found that male rats, that had larger B.W. and pituitary GH content than age-paired females, developed larger goitres. However, both male and female rats were in a hypothyroid condition of comparable degree as judged by the thyroidal iodine content and the plasma PBI and TSH levels. When all the data on the PTU or KClO4-treated male and female rats of varying age and B.W. were considered together, it was observed that the weights of the thyroids increased proportionally to B.W. However, a difference in the slope of the regression of the thyroid weight over B.W. was found between male and female rats, due to the fact that adult male rats develop larger goitres than female animals. In addition, in the male rats treated with PTU, gonadectomy decreased the B.W., pituitary content of GH-like protein and, concomitantly, the size of the goitre decreased; an opposite effect was induced by ovariectomy on the female animals. However, when goitrogenesis was induced in weight-paired adult rats of both sexes, the male animals still developed larger goitres than the females. Among all the parameters studied here, the only ones which appeared to bear a consistent relationship with the size of the goitres in rats of different sexes, treated with a given goitrogen, were the rate of body growth and the amount of a pituitary GH-like protein found before the onset of the goitrogen treatment. Moreover, though the pituitary content of the GH-like protein decreased as a consequence of goitrogen treatment, it was still somewhat higher in male that in female animals. The present results suggest that GH may somehow be involved in the mechanism by which male and female rats on goitrogens develop goitres of different sizes, despite equally high plasma TSH levels.

scholarly journals Analysis of sex differences in dietary copper-fructose interaction-induced alterations of gut microbial activity in relation to hepatic steatosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ming Song ◽  
Fang Yuan ◽  
Xiaohong Li ◽  
Xipeng Ma ◽  
Xinmin Yin ◽  
...  
Keyword(s):  
Sex Differences ◽  
Microbial Activity ◽  
Hepatic Steatosis ◽  
Female Rats ◽  
Male Rats ◽  
Calorie Intake ◽  
Dietary Copper ◽  
Male And Female ◽  
Male And Female Rats ◽  
Rrna Sequencing

Abstract Background Inadequate copper intake and increased fructose consumption represent two important nutritional problems in the USA. Dietary copper-fructose interactions alter gut microbial activity and contribute to the development of nonalcoholic fatty liver disease (NAFLD). The aim of this study is to determine whether dietary copper-fructose interactions alter gut microbial activity in a sex-differential manner and whether sex differences in gut microbial activity are associated with sex differences in hepatic steatosis. Methods Male and female weanling Sprague-Dawley (SD) rats were fed ad libitum with an AIN-93G purified rodent diet with defined copper content for 8 weeks. The copper content is 6 mg/kg and 1.5 mg/kg in adequate copper diet (CuA) and marginal copper diet (CuM), respectively. Animals had free access to either deionized water or deionized water containing 10% fructose (F) (w/v) as the only drink during the experiment. Body weight, calorie intake, plasma alanine aminotransferase, aspartate aminotransferase, and liver histology as well as liver triglyceride were evaluated. Fecal microbial contents were analyzed by 16S ribosomal RNA (16S rRNA) sequencing. Fecal and cecal short-chain fatty acids (SCFAs) were determined by gas chromatography-mass spectrometry (GC-MS). Results Male and female rats exhibit similar trends of changes in the body weight gain and calorie intake in response to dietary copper and fructose, with a generally higher level in male rats. Several female rats in the CuAF group developed mild steatosis, while no obvious steatosis was observed in male rats fed with CuAF or CuMF diets. Fecal 16S rRNA sequencing analysis revealed distinct alterations of the gut microbiome in male and female rats. Linear discriminant analysis (LDA) effect size (LEfSe) identified sex-specific abundant taxa in different groups. Further, total SCFAs, as well as, butyrate were decreased in a more pronounced manner in female CuMF rats than in male rats. Of note, the decreased SCFAs are concomitant with the reduced SCFA producers, but not correlated to hepatic steatosis. Conclusions Our data demonstrated sex differences in the alterations of gut microbial abundance, activities, and hepatic steatosis in response to dietary copper-fructose interaction in rats. The correlation between sex differences in metabolic phenotypes and alterations of gut microbial activities remains elusive.

scholarly journals κ-opioid receptor antagonism reverses heroin withdrawal-induced hyperalgesia in male and female rats

2021 ◽  
pp. 100325
Author(s):  
Renata C.N. Marchette ◽  
Adriana Gregory-Flores ◽  
Brendan J. Tunstall ◽  
Erika R. Carlson ◽  
Shelley N. Jackson ◽  
...  
Keyword(s):  
Opioid Receptor ◽  
Female Rats ◽  
Male And Female ◽  
Receptor Antagonism ◽  
Male And Female Rats

scholarly journals Sex Differences in Escalated Methamphetamine Self-Administration and Altered Gene Expression Associated With Incubation of Methamphetamine Seeking

2019 ◽  
Vol 22 (11) ◽  
pp. 710-723 ◽  
Author(s):  
Atul P Daiwile ◽  
Subramaniam Jayanthi ◽  
Bruce Ladenheim ◽  
Michael T McCoy ◽  
Christie Brannock ◽  
...  
Keyword(s):  
Sex Differences ◽  
Nucleus Accumbens ◽  
Fixed Ratio ◽  
Female Rats ◽  
Male Rats ◽  
Mrna Levels ◽  
Self Administration ◽  
Male And Female ◽  
Orexin Receptors ◽  
Male And Female Rats

Abstract Background Methamphetamine (METH) use disorder is prevalent worldwide. There are reports of sex differences in quantities of drug used and relapses to drug use among individuals with METH use disorder. However, the molecular neurobiology of these potential sex differences remains unknown. Methods We trained rats to self-administer METH (0. 1 mg/kg/infusion, i.v.) on an fixed-ratio-1 schedule for 20 days using two 3-hour daily METH sessions separated by 30-minute breaks. At the end of self-administration training, rats underwent tests of cue-induced METH seeking on withdrawal days 3 and 30. Twenty-four hours later, nucleus accumbens was dissected and then used to measure neuropeptide mRNA levels. Results Behavioral results show that male rats increased the number of METH infusions earlier during self-administration training and took more METH than females. Both male and female rats could be further divided into 2 phenotypes labeled high and low takers based on the degree of escalation that they exhibited during the course of the METH self-administration experiment. Both males and females exhibited incubation of METH seeking after 30 days of forced withdrawal. Females had higher basal mRNA levels of dynorphin and hypocretin/orexin receptors than males, whereas males expressed higher vasopressin mRNA levels than females under saline and METH conditions. Unexpectedly, only males showed increased expression of nucleus accumbens dynorphin after METH self-administration. Moreover, there were significant correlations between nucleus accumbens Hcrtr1, Hcrtr2, Crhr2, and Avpr1b mRNA levels and cue-induced METH seeking only in female rats. Conclusion Our results identify some behavioral and molecular differences between male and female rats that had self-administered METH. Sexual dimorphism in responses to METH exposure should be considered when developing potential therapeutic agents against METH use disorder.

scholarly journals The Preventive Effects of Diminazene Aceturate in Renal Ischemia/Reperfusion Injury in Male and Female Rats

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Maryam Malek ◽  
Mehdi Nematbakhsh
Keyword(s):  
Angiotensin Ii ◽  
Angiotensin Converting Enzyme ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Female Rats ◽  
Male Rats ◽  
Converting Enzyme ◽  
Diminazene Aceturate ◽  
Male And Female ◽  
Male And Female Rats

Background. Angiotensin-converting enzyme 2/angiotensin (1-7)/Mas receptor (ACE2/Ang-1-7/MasR) appears to counteract most of the deleterious actions of angiotensin-converting enzyme/angiotensin II/angiotensin II receptor 1 (ACE/Ang II/AT1R) in renal ischemia/reperfusion (I/R) injury but ACE2 activity and its levels are sexually dimorphic in the kidney. This study was designed to evaluate the effects of activation endogenous ACE2 using the diminazene aceturate (DIZE) in renal I/R injury in male and female rats.Methods. 36 Wistar rats were divided into two groups of male and female and each group distinct to three subgroups (n=6). I/R group was subjected to 45 min of bilateral ischemia and 24 h of reperfusion, while treatment group received DIZE (15 mg/kg/day) for three days before the induction of I/R. The other group was assigned as the sham-operated group.Results. DIZE treatment in male rats caused a significant decrease in blood urea nitrogen (BUN), creatinine, liver functional indices, serum malondialdehyde (MDA), and increase kidney nitrite levels (P<0.05), and in female rats a significant increase in creatinine and decrease serum nitrite levels compared to the I/R group (P<0.05).Conclusions. DIZE may protect the male kidney from renal I/RI through antioxidant activity and elevation of circulating nitrite level.

Gender-based differences in the effect of dietary cholesterol in rats

2012 ◽  
Vol 7 (6) ◽  
pp. 980-986 ◽  
Author(s):  
Milan Marounek ◽  
Zdeněk Volek ◽  
Eva Skřivanová ◽  
Marian Czauderna
Keyword(s):  
Dietary Cholesterol ◽  
Female Rats ◽  
Male Rats ◽  
Cholesterol Concentration ◽  
Hepatic Cholesterol ◽  
Bile Acid Concentration ◽  
Male And Female ◽  
Relative Expression ◽  
Male And Female Rats ◽  
Cholesterol Supplementation

AbstractMale and female rats were fed diets supplemented with cholesterol and palm fat at 10 and 50 g/kg, respectively; serum, hepatic tissue and faeces were analysed. Cholesterol supplementation significantly increased serum and hepatic cholesterol both in male and female rats. Male and female rats fed the cholesterol-containing diet differed significantly in serum cholesterol concentration (2.48 µmol/mL vs 2.92 µmol/mL), concentration of serum triacylglycerols, but not in hepatic cholesterol concentration. The serum and hepatic cholesterol concentrations correlated non-significantly in male rats (r=0.491; P=0.063) and significantly in female rats (r=0.818; P<0.001). Cholesterol supplementation non-significantly decreased relative expression of the hepatic LDL receptor gene and significantly increased relative expression of the hepatic cholesterol 7α-hydroxylase gene in rats of both genders. The faeces of control rats contained similar amounts of cholesterol and bile acids. Cholesterol supplementation increased cholesterol concentration 10 times in the faeces of male rats and 12 times in faeces of female rats. The corresponding increases of bile acid concentration were much lower (83% in male rats and 108% in female rats). It can be concluded that the effects of cholesterol supplementation were more pronounced in female than in male rats.

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