scholarly journals Body weight ratio of male and female rats reared on various diets in relation to food efficiency ratio and longevity

1969 ◽  
Vol 3 (2) ◽  
pp. 119-127 ◽  
Author(s):  
L. M. Dalderup
Keyword(s):  
Age Groups ◽  
Weight Ratio ◽  
Later Life ◽  
Female Rats ◽  
Efficiency Ratio ◽  
Male And Female ◽  
Food Efficiency ◽  
Male And Female Rats ◽  
Younger Age ◽  
Food Efficiency Ratio

The ratio of the bodyweights of male and female rats, together with the weight of the females, seems to give valuable information as to the biological value of an experimental food as a whole and to the lifespan expectancy. Extremes of the bodyweight ratios are 0.9 and 2.0, the lower ratios applying to younger age groups and to old animals, the higher ratios to the ages in between. There is evidence that diets which are most favourable with regard to longevity give rise to maximum ratios between 1.5 and 1.6, which are maintained during later life. The females give always less response to dietary measures and are less disturbed by very bad quality rations than the males. Their lifespan is often longer than that of the males. The bodyweight ratio has within reasonable limits the same numerical value as the ratio of food efficiencies of male and female animals; the weight ratio is always very simple to obtain, whereas measurement of food-efficiency ratio requires much more work.

Comparison of the acute hematotoxicity of 2-butoxyethanol in male and female F344 rats

2000 ◽  
Vol 19 (3) ◽  
pp. 185-192 ◽  
Author(s):  
B I Ghanayem ◽  
S M Ward ◽  
B Chanas ◽  
A Nyska
Keyword(s):  
Body Weight ◽  
Cell Volume ◽  
Weight Ratio ◽  
Female Rats ◽  
Male Rats ◽  
Mean Cell Volume ◽  
Male And Female ◽  
Male And Female Rats ◽  
Butoxyacetic Acid ◽  
F344 Rats

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.

CIRCADIAN FLUCTUATIONS OF SERUM HORMONE LEVELS IN PREPUBERTAL MALE AND FEMALE RATS

1976 ◽  
Vol 83 (2) ◽  
pp. 269-279 ◽  
Author(s):  
K. D. Döhler ◽  
W. Wuttke
Keyword(s):  
Age Groups ◽  
Serum Testosterone ◽  
Female Rats ◽  
Serum Prolactin ◽  
Male And Female ◽  
Hormone Levels ◽  
Male And Female Rats ◽  
Serum Lh ◽  
Serum Hormone ◽  
Old Females

ABSTRACT Diurnal variations in serum hormone levels during 2 different stages of prepubertal development were investigated in male and female rats. Groups of 13 to 18 and 25 to 30 day old male and female rats were decapitated at 4-hour by intervals during a period of 24 h. Their blood was collected and hormones were measured by radio-immunoassay. FSH levels were constantly high in 13 to 18, but low in 25 to 30 day old females. FSH was low in younger males, and significantly higher but without diurnal fluctuations in the older males. Serum LH was low in approximately 40% of the 13 to 18 day old females, while 40% had moderately high levels, and the remaining females extremely high levels of the hormone. Most of the extremely high LH peaks were found at 15.00 h and some at 03.00 h. Older females and males of both age groups had constantly low serum LH levels. Serum oestradiol was high in males and females during days 13 to 18, but it was lower in the 25 to 30 day old animals. In the young females prolactin was slightly elevated between 15.00 h and 19.00 h, while in the males the serum prolactin fluctuations were not significant. Serum testosterone was low in females at all times. The 13 to 18 day old males had higher testosterone levels than the 25 to 30 day old males. Both groups showed slight, but insignificant fluctuations in serum testosterone. These results confirm result published previously and furthermore they demonstrate the existence of circasemedian or circadian rhythms for both the gonadotrophins and gonadal steroids. These results, also suggest that the maturation of the positive feedback action of oestradiol on gonadotrophin release in female rats occurs between day 10 and 20.

THE EFFECTS OF AN ALPHA ADRENERGIC BLOCKER ON THYROCALCITONIN ACTIVITY IN MALE AND FEMALE RATS

1973 ◽  
Vol 73 (1) ◽  
pp. 64-68
Author(s):  
G. N. Currie ◽  
D. L. Black
Keyword(s):  
Serum Calcium ◽  
Age Groups ◽  
Blocking Agent ◽  
Female Rats ◽  
Male Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Adrenergic Blocker ◽  
Effective Level ◽  
Adrenergic Blocking

ABSTRACT When an alpha adrenergic blocking agent, phenoxybenzamine, was given to rats prior to the administration of a non-effective level of thyrocalcitonin (TC) there resulted a significant fall in serum calcium one hour following TC treatment. This response was observed in two different age groups of female rats but did not occur in male rats.

Maternal age, reproduction and chromosomal aberrations in Wistar derived rats

1994 ◽  
Vol 28 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Adolf Niggeschulze ◽  
Alexander Kast
Keyword(s):  
Risk Assessment ◽  
Bone Marrow ◽  
Maternal Age ◽  
Age Groups ◽  
Female Rats ◽  
Age Group ◽  
Male And Female ◽  
Male And Female Rats ◽  
Copulation Rate ◽  
New Compounds

The fertility of rats ranges from one to 18 months. In standard teratogenicity testing young, mature females are used which may not reflect the situation in women above 35 years old. Reproduction among different age groups of Wistar ats (strain Chbb : THOM) was compared at 3, 6, 9, 12, 15 and 18 months. At least 20 virgin females were inseminated per age group. The copulation rate did not differ between the groups. From the maternal age of 12 months, the pregnancy rate was significantly decreased, from the age of 9 months, the litter values were significantly lowered and the resorption rates were increased. Maternal age did not influence the incidence of fetal variations and malformations. Additionally, the chromosomal aberration rate in the bone marrow was evaluated in male and female rats. Twelve animals of each sex were scheduled per group, and studied at the age of 1, 3, 6, 12, 15, 18, 21 or 24 months. In males, the aberration rate increased continuously from 0.18 through 3%, while in females the increase continued from 0.33 to 2.29% at 15 months old when a plateau was reached. When testing new compounds for embryotoxicity or genotoxicity in female rats, the animals should be of comparable age to man in order to avoid a misinterpretation of spontaneous abnormalities. From these studies, however, it was concluded that the use of higher age groups of female rats in teratogenicity studies would not improve the risk assessment.

scholarly journals Gender differences in doublecortin expression in the dentate gyrus of the Wistar rat during development

2020 ◽  
Vol 14 (2) ◽  
pp. 111-116
Author(s):  
Özlem Tuğçe Çilingir Kaya ◽  
Sercan Doğukan Yıldız ◽  
Nisva Hilal Levent ◽  
Esra Bihter Gürler ◽  
Ümit Süleyman Şehirli ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Developmental Process ◽  
Age Groups ◽  
Wistar Rat ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Female Wistar Rats ◽  
Male Wistar Rats ◽  
Males And Females

Objectives: Neurogenesis is the formation process of functional neurons from progenitor cells which continues during lifetime. Alterations in neurogenesis is associated with neurodegenerative disorders (ND). Different mechanisms underlie the ND in males and females which may be related to neurogenesis. In this study, we aimed to investigate the developmental process of neurogenesis in the hippocampus of male and female rats at different ages and shed light on the effect of gender difference on ND. Methods: Brains were obtained from 7, 14, 21 days and 3-month-old male and female Wistar rats following intracardiac perfusion and processed for immunohistochemical and immunoflorescence staining. Doublecortin protein (DCX) was used as a marker of newly-born neuroblasts to determine neurogenesis. Results: DCX immunoreactive (-ir) cells were dispersed throughout the granular and subgranular layers of DG in 7-days-old group in both genders. However, in the 14 and 21 days old groups, DCX-ir cells were observed only in the subgranular zone in the sections labelled with both immunohistochemistry (IHC) and immunoflourescent (IF) methods. In all age groups, female rats had a tendency to increase in DCX immunoreactivity when compared to that of male Wistar rats. Conclusion: DCX-ir cells may be localized in different parts of DG during development. The number of newly born neurons showed a tendency to increase in female rats in all groups. Further studies are needed to understand the reason for differences in the normal developmental neurogenesis process between two genders.

THE PITUITARY AND ADRENAL RESPONSES TO ADMINISTRATION OF OESTRIOL IN GONADECTOMIZED RATS

1961 ◽  
Vol 38 (1) ◽  
pp. 50-58 ◽  
Author(s):  
N. E. Borglin ◽  
L. Bjersing
Keyword(s):  
Pituitary Gland ◽  
Adrenal Cortex ◽  
Clinical Experience ◽  
Uterine Cervix ◽  
Morphological Changes ◽  
Physiological Significance ◽  
Female Rats ◽  
Experimental Conditions ◽  
Male And Female ◽  
Male And Female Rats

ABSTRACT Oestriol (oestra-1,3,5(10)-triene-3,16α,17β-triol) is a weakly oestrogenic substance which, however, in contrast to what was formerly believed, is of physiological significance. Its effect is localized largely to the uterine cervix and vagina. Clinical experience argues both for and against an effect on the pituitary gland. This investigation is concerned with the morphological changes in the pituitary gland and adrenal cortex of gonadectomized male and female rats after the injection of oestriol. It was found that oestriol has the same type of action on these glands as other oestrogens, but under the experimental conditions used, this effect proved much weaker than that produced by oestradiol (oestra-1,3,5(10)-triene-3,17β-diol).

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.

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