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.

INFLUENCE OF GONADAL HORMONES ON THE ACTION OF CALCITONIN IN THE RAT

1971 ◽  
Vol 68 (3) ◽  
pp. 585-596 ◽  
Author(s):  
O. Helmer Serensen ◽  
Inge Hindberg
Keyword(s):  
Serum Calcium ◽  
Thyroid Tissue ◽  
Gonadal Hormones ◽  
Term Treatment ◽  
Female Rats ◽  
Short Term ◽  
Oestrogen Treatment ◽  
Male And Female Rats ◽  
Long Term Treatment

ABSTRACT The influence of short-term and long-term treatment with gonadal hormones on the response to calcitonin was investigated in the rat. Oestrogen-treatment, short-term as well as long-term, resulted in a reduced responsiveness to calcitonin. Long-term treatment with androgens enhanced the hypocalcaemic effect of calcitonin in castrated rats of either sex, but reduced the effect in intact animals. No sex differences could be registered in the sensitivity to calcitonin, when intact animals were compared according to age, while marked differences were observed, when the animals were compared according to weight. There was a linear decrease in the response to calcitonin with increasing age in rats of both sexes. An intraperitoneal calcium load was followed by an acute rise in the serum calcium levels. The adult animals counteracted the hypercalcaemia more slowly than the young ones. Significant differences also occurred between male and female rats, the rise in the serum calcium concentration being much more pronounced in the latter group. The hypocalcaemic activity of thyroid tissue from rats of both sexes and of various ages showed considerable variations, but no differences correlated to age or sex.

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

Effects of short-term and long-term androgen treatment on the diaphragm in male and female rats

1993 ◽  
Vol 75 (3) ◽  
pp. 1140-1149 ◽  
Author(s):  
D. J. Prezant ◽  
D. E. Valentine ◽  
E. I. Gentry ◽  
B. Richner ◽  
J. Cahill ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Fiber Type ◽  
Female Rats ◽  
Short Term ◽  
Male And Female ◽  
Testosterone Treatment ◽  
Male And Female Rats ◽  
Long Term Treatment ◽  
Significant Difference

The effects of short-term (2.5 wk) and long-term (10 wk) testosterone propionate (2.5 mg/day; 5 days/wk) treatment on diaphragm contractility, fatigue resistance, 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 direct stimulation at 37 degrees C. The fatigue paradigm consisted of 30 trains/min at 5 Hz (50% duty cycle) for 10 min. Fatigue resistance indexes were calculated as postfatigue divided by baseline forces. In females but not males, testosterone treatment produced significant increases in body weight, costal diaphragm weight, and contractility and significant decreases in fatigue resistance indexes. The interaction between testosterone treatment and the duration of treatment was significant, with the increase in contractility (females) being significant after short-term but not long-term treatment. No significant difference in fiber type proportions or areas was observed, regardless of treatment duration or the preexperimental, basal circulating level of androgen.

THE INFLUENCE OF A SINGLE HIGH DOSE OF OESTRADIOL BENZOATE ON THE ICSH-CONTENT IN THE SERUM OF GONADECTOMIZED MALE AND FEMALE RATS

1965 ◽  
Vol 49 (2) ◽  
pp. 231-238 ◽  
Author(s):  
T. Swelheim
Keyword(s):  
Anterior Pituitary ◽  
Single Injection ◽  
Female Rats ◽  
Male Rats ◽  
Ventral Prostate ◽  
High Dose ◽  
Male And Female ◽  
Single High Dose ◽  
Male And Female Rats ◽  
Oestradiol Benzoate

ABSTRACT A single injection of 50 μg oestradiol benzoate, administered at 11 a.m. to adult female rats which had been spayed 14 days previously and had since been treated with 0.5 μg oestradiol benzoate daily, led to an increase in the ICSH-content of the serum, which was determined 29 hours after the injection. In an identical experimental design a decrease in the ICSH-content of the serum was found in adult male rats. ICSH-determinations were carried out by the ventral prostate assay. A stimulating effect upon the ventral prostate of oestrogen present in the serum used for the above determinations was excluded. At the time when the changes in the serum were established, there were no demonstrable changes in the ICSH-content of the anterior pituitary gland in both sexes. The existence of a fundamental sex difference in the response to a single high dose of oestrogen is suggested.

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.

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