scholarly journals Oestrogenic effects of neonatal administration of raloxifene on hypothalamic-pituitary-gonadal axis in male and female rats

Reproduction ◽  
2001 ◽  
pp. 915-924 ◽  
Author(s):  
L Pinilla ◽  
LC Gonzalez ◽  
F Gaytan ◽  
M Tena-Sempere ◽  
E Aguilar

Selective oestrogen receptor modulators constitute a family of drugs that are used increasingly in the management of oestrogen-associated pathology. Raloxifene is a selective oestrogen receptor modulator that is used to treat and prevent osteoporosis in post-menopausal women. The actions of raloxifene on bone, breast, uterus and serum cholesterol concentrations have been widely analysed, but very few studies have investigated the possible actions of this drug on the central nervous system. The central nervous system of the newborn rat is very sensitive to oestrogen action. In this study a series of experiments was conducted to analyse the effects of different doses of raloxifene (50, 100, 250 or 500 microg per rat per day) administered to neonatal rats on days 1-5 of age. Female rats treated with raloxifene showed decreased gonadotrophin secretion, hyperprolactinaemia, advanced vaginal opening, decreased body weight, persistent presence of cornified epithelial cells in vaginal smears, anovulation, inhibition of positive feedback between oestradiol and LH, and infertility. Male rats showed delayed balanopreputial separation, reduced body weight and hyperprolactinaemia. All these changes resemble those obtained after neonatal administration of oestradiol benzoate, thus indicating, for the first time, that raloxifene exerts an oestrogenic action on the hypothalamic-pituitary structures controlling reproductive function in rats.

1951 ◽  
Vol 7 (3) ◽  
pp. 271-279 ◽  
Author(s):  
J. T. EAYRS

The growth of the body and central nervous system and the emergence of stereotyped behaviour have been studied in male and female rats during the first 24 days of life. The effects of daily injections of equine gonadotrophin on these measures have also been investigated. The weight of the body and of the central nervous system was significantly less in the female than in the male. The daily administration of 10 i.u. of equine gonadotrophin was without effect on either. The movements of the trunk and limbs concerned in the body-righting reflex became coordinated more slowly in the gonadotrophin-injected animals than in their litter-mate controls. At 15 days old, male rats were able to right in mid-air more successfully than litter-mate females. The placing reflex appeared earlier in the male than in the female. Its appearance was accelerated in the females given gonadotrophin, but not in the males. In the ventral funiculus of the spinal cord of 24-day-old experimental animals, the axis cylinders occupied more space relative to that occupied by myelin than did those of the controls. The total amount of myelin present was unchanged. There was no sex difference in the progress of myelination in the spinal cord. The significance of these findings in relation to the secretion of sex hormones is discussed. It is suggested that the secretion of androgen may be responsible for an acceleration of nervous maturation.


2018 ◽  
Vol 66 (3) ◽  
pp. 462-473
Author(s):  
Lucía López ◽  
María José Zuluaga ◽  
Patricia Lagos ◽  
Daniella Agrati ◽  
Gabriela Bedó

1986 ◽  
Vol 61 (2) ◽  
pp. 780-784 ◽  
Author(s):  
E. H. Schlenker ◽  
M. Goldman

In this study ventilation was evaluated in 12-mo-old male and female rats who had received large doses of aspartic acid neonatally. Rats of both sexes treated with aspartic acid were obese, stunted, and exhibited hypogonadism. Although metabolic rates of the aspartic acid-treated rats were not different compared with sex-matched controls, ventilatory patterns were different. Aspartic acid-treated females breathed with a smaller tidal volume (VT), higher frequency (f), and similar minute ventilation (VE) compared with control females. This pattern is commonly observed in many patients who are obese. The aspartic acid-treated females responded to hypercapnic and hypoxic challenges by increasing f more than VT. Tissue pocket gases (PCO2 and PO2) of aspartic acid-treated females were normal. In contrast, aspartic acid-treated males hypoventilated compared with control males. Tissue pocket gas values suggested that aspartic acid-treated males were hypoxemic and hypercapnic. Moreover, the response of aspartic acid-treated males to hypercapnia was parallel to but was less than that of control male rats. The ventilatory response of aspartic acid-treated male rats to hypoxia was blunted. This study has shown that neonatal administration of aspartic acid causes a decreased ventilation and blunted response to hypoxia in adult male but not female rats.


2014 ◽  
Vol 2 (4) ◽  
pp. e00282 ◽  
Author(s):  
Heather E. Held ◽  
Raffaele Pilla ◽  
Geoffrey E. Ciarlone ◽  
Carol S. Landon ◽  
Jay B. Dean

2008 ◽  
Vol 100 (6) ◽  
pp. 1192-1199 ◽  
Author(s):  
Pascale Rozan ◽  
Amine Nejdi ◽  
Sophie Hidalgo ◽  
Jean-François Bisson ◽  
Didier Desor ◽  
...  

Ageing is associated with changes in physiology and morphology; nutritional strategies to decrease morbidity and to prolong life are of high interest. The aim of the study was to investigate the effects of lifelong supplementation with an oligofructose-enriched inulin on morphological and biological markers and lifespan in male and female rats. Male and female rats, age 3 months, were randomised into two groups to receive either a diet with 10 % of an oligofructose-enriched inulin (Synergy1) or a standard diet (control) for 27 months. The rats were weighed every 2 weeks and their food intake was evaluated on four successive days every 4–6 weeks. Samples were taken at 12, 18 and 24 months of age. During the whole intervention period, male rats receiving Synergy1 (SYN1-M) displayed lower body weight, cholesterol and plasma triacylglycerolaemia compared with the controls (Cont-M). The survival rate at 24 months of age of SYN1-M rats was 35·3 % greater than that of Cont-M rats. In female rats, the Synergy1 supplementation (SYN1-F) group also reduced body weight, cholesterol and triacylglycerolaemia levels, but results were less consistent over the experiment. The survival rate at 24 months of age in SYN1-F rats was 33·3 % greater compared with that of the control (Cont-F) group. To conclude, lifelong intervention with Synergy1 improved biological markers during ageing and survival rate (lifespan) of rats.


1987 ◽  
Vol 414 (1) ◽  
pp. 133-137 ◽  
Author(s):  
Andy M. Hughes ◽  
Barry J. Everitt ◽  
Stafford L. Lightman ◽  
Kathryn Todd

2000 ◽  
Vol 19 (3) ◽  
pp. 185-192 ◽  
Author(s):  
B I Ghanayem ◽  
S M Ward ◽  
B Chanas ◽  
A Nyska

Administration of 2-butoxyethanol (BE) to rodents causes acute hemolytic anemia, and metabolic activation of BE to butoxyacetic acid (BAA) is required for the development of this effect. Recent studies have shown that female rats treated with BE exhibit a variety of histopathologic lesions that are absent in males and many of these lesions are attributed to the hemolytic effects of BE. Current studies were designed to compare the acute hematotoxicity of BE in male and female F344 rats. Rats were treated with 250 mg BE/kg body weight or water (control; 5 ml/kg) by gavage. At 4, 8, or 24 h after dosing, rats were anesthetized, blood was collected by cardiac puncture, and various blood parameters were measured. BE resulted in a time-dependent swelling of erythrocytes as evidenced by an early increase in hematocrit (Hct) and mean cell volume (MCV) in male rats. In contrast, increased Hct in female rats did not accompany an increase in MCV. It is likely that hemolysis was so severe at 4 h that Hct exhibited a decline in female rats at that time point. Subsequently, red blood cell (RBCs), hemoglobin concentration (Hgb), and Hct declined as hemolysis progressed. However, the onset of BE-induced hemolysis was faster in female compared to male rats. These effects were also associated with a significant increase in the spleen weight to body weight ratio. Blood smears were also prepared and morphological changes evaluated by light microscopy included stomatocytosis, spherocytosis, and schistocytosis. Furthermore, aggregation of RBCs in female rats as evidenced by increased formation of rouleaux was observed at 24 h after BE administration. These effects were observed earlier and more frequently in female rats. No differences in the sensitivity of RBCs obtained from male and female rats and exposed to butoxyacetic acid (BAA) in vitro was observed as determined by measuring the packed cell volume. In conclusion, these data suggest that female rats are more sensitive to hemolysis and morphological alterations of erythrocytes induced by BE during the first 24 h after exposure compared to males. It is likely that the greater sensitivity of female rats to BE effects on RBCs may account for the reported development of thrombosis and tissue infarction in female rats.


1985 ◽  
Vol 42 (5) ◽  
pp. 1063-1071 ◽  
Author(s):  
S C Woods ◽  
D Porte ◽  
E Bobbioni ◽  
E Ionescu ◽  
J F Sauter ◽  
...  

1995 ◽  
Vol 14 (2) ◽  
pp. 119-128 ◽  
Author(s):  
A. M. Hoberman ◽  
M. S. Christian ◽  
R. Roth ◽  
S. Lovre ◽  
F. Koschier

Clarified slurry oil (CSO, CAS #64741–62-4; also termed carbon black oil), a residual product from the fluidized catalytic cracker in petroleum refining, has the potential to be absorbed through the skin. The reproductive toxicity of CSO in male and female rats was evaluated by the topical route of exposure. CSO was administered dermally to male rats at dosages of 0 (vehicle), 0.1, 1, 10, 50, and 250 mg/kg/day for 70 days before a cohabitation period with untreated female rats. CSO was administered also to female rats at the same dosages for 14 days prior to a 7-day cohabitation period and continuing until Day 0 of gestation (day spermatozoa was present in a smear of the vaginal contents or a copulatory plug was observed in situ). The dosage volume in both experiments was 1 ml/kg, adjusted on each day of dosage based on individual body weights recorded immediately before application of CSO. Under the conditions of these experiments, the paternal no-observable-adverse-effect-level (NOAEL) for CSO administered dermally was 1 mg/kg/day. The 10, 50, and 250 mg/kg/day dosages of CSO caused body weight losses and/or decreased body weight gains and reduced feed consumption. The 50- and 250-mg/kg/day dosages also caused adverse clinical effects. No mating, fertility, or testicular end points in male rats were affected by the highest dosages tested; therefore, the reproductive NOAEL for male rats is <250 mg/kg/day. The maternal NOAEL for CSO administered dermally was 10 mg/kg/day. The 50-and 250-mg/kg/day dosages of CSO reduced body weight gains; 250 mg/kg/day also reduced feed consumption. There were no adverse effects on gonadal function, estrous cycles, mating behavior, conception rates, or reproductive organ weights; therefore, the reproductive NOAEL for female rats administered CSO dermally is at least 250 mg/kg/day.


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