Pathophysiology characteristics of the experimental model of obesity in female rats induced neonatal administration of monosodium glutamate

The pineal gland synthesizes melatonin exclusively at night, which gives melatonin the characteristic of a temporal synchronizer of the physiological systems. Melatonin is a regulator of insulin activities centrally and also peripherally and its synthesis is reduced in diabetes. Since monosodium glutamate (MSG) is often used to induce the type 2 diabetic and metabolic syndrome in animal models, the purpose of this work is to evaluate the potential effects of MSG given to neonates on the pineal melatonin synthesis in different aged male and female rats. Wistar rats were subcutaneously injected with MSG (4mg/g/day) or saline solution (0.9%) from the second to eighth post-natal day. The circadian profiles both melatonin levels and AANAT activity were monitored at different ages. Body weight, naso-anal length, adipose tissues weight, GTT, ITT and serum insulin levels were also evaluated. Typical obesity with the neonatal MSG treatment was observed, indicated by a great increase in adipose depots without a concurrent increase in body weight. MSG treatment did not cause hyperglycemia or glucose intolerance, but induced insulin resistance. An increase of melatonin synthesis at ZT 15 with phase advance was observed in in some animals. The AANAT activity was positively parallel to the melatonin circadian profile. It seems that MSG causes hypothalamic obesity which may increase AANAT activity and melatonin production in pineal gland. These effects were not temporally correlated with insulin resistance and hyperinsulinemia indicating the hypothalamic lesions, particularly in arcuate nucleus induced by MSG in early age, as the principal cause of the increase in melatonin production.

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Electron microscopic changes of lymph nodes during correction of sodium glutamate action by melatonin

Reports of Morphology ◽

10.31393/morphology-journal-2020-26(1)-09 ◽

2020 ◽

Vol 26 (1) ◽

pp. 59-64 ◽

Cited By ~ 1

Author(s):

T.V. Harapko

Keyword(s):

Lymph Nodes ◽

Monosodium Glutamate ◽

Reproductive Age ◽

Female Rats ◽

Mesenteric Lymph Nodes ◽

Electron Microscopic ◽

Male And Female ◽

White Rats ◽

Mesenteric Lymph ◽

Male And Female Rats

The effect of monosodium glutamate on lymphoid organs remains insufficiently studied. Also, no less relevant is the issue of correction of changes caused by the action of monosodium glutamate. The aim of the study was to study the electron microscopic changes in the parenchyma of the lymph nodes of rats under the action of monosodium glutamate for six weeks and during correction with melatonin. The experimental study was performed on 66 white male and female rats of reproductive age. The structure of mesenteric lymph nodes of white rats under the conditions of physiological norm at the electron microscopic level was studied in 10 intact animals. Experimental animals were divided into 4 groups, each with 10 animals. The control was 16 white rats, which instead of a high-calorie diet (HCD) received a standard diet of vivarium. HCD was achieved by adding to the diet of monosodium glutamate at a dose of 0.07 g/kg body weight of rats. The dose of melatonin was 10 mg/kg body weight of rats, administered orally daily at the same time in the afternoon. The electron microscopic structure of the mesenteric lymph nodes of male and female rats of reproductive age of the intact and control groups corresponds to the species norm. The study showed that monosodium glutamate causes changes in the parenchyma of the lymph nodes as in alimentary obesity. After six weeks of HCD, the number of apoptically altered lymphocytes increases. That part of lymphocytes, which has no signs of karyorrhexis or karyolysis, has a karyolemma with deep intussusception, the cytoplasm is enlightened, the tubules of the granular endoplasmic reticulum in cells with signs of edema, dilated, mitochondrial ridges swollen, damaged. There are profound destructive changes in the cellular composition of the organ and violations at the level of all parts of the vascular bed. After six weeks of melatonin correction, the number of macrophages and plasma cells decreased, in some lymphocytes the nucleolus is not clearly expressed, the karyolemma is uneven, the cytoplasm is enlightened, the number of osmophilic (fatty) inclusions decreases both in the intercellular space and in the cytoplasm of the cell. Therefore, the introduction of melatonin led to a significant restoration of the structural organization, and hence the function of this organ.

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Aspartic acid administered neonatally affects ventilation of male and female rats differently

Journal of Applied Physiology ◽

10.1152/jappl.1986.61.2.780 ◽

1986 ◽

Vol 61 (2) ◽

pp. 780-784 ◽

Cited By ~ 16

Author(s):

E. H. Schlenker ◽

M. Goldman

Keyword(s):

Aspartic Acid ◽

Ventilatory Response ◽

Minute Ventilation ◽

Female Rats ◽

Male Rats ◽

Metabolic Rates ◽

Control Male ◽

Male And Female ◽

Male And Female Rats ◽

Neonatal Administration

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.

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Ontogeny of GH mRNA and GH secretion in male and female rats: regulation by GH-releasing hormone

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1993.265.2.e236 ◽

1993 ◽

Vol 265 (2) ◽

pp. E236-E242 ◽

Cited By ~ 1

Author(s):

Z. Hu ◽

R. D. Friberg ◽

A. L. Barkan

Keyword(s):

Growth Rate ◽

Monosodium Glutamate ◽

Somatic Growth ◽

Female Rats ◽

Growth Spurt ◽

Pubertal Growth Spurt ◽

Releasing Hormone ◽

Pubertal Growth ◽

Igf I ◽

Mrna Content

Growth hormone-releasing hormone (GHRH) has been shown in vitro to increase proliferation of pituitary somatotrophs, to increase transcription of the GH gene, to promote accumulation of GH mRNA, and to stimulate GH release. The in vivo involvement of hypothalamic GHRH in regulating GH mRNA content had never been clearly documented. We studied pituitary GH mRNA and GH contents and serum concentrations of GH and insulin-like growth factor I (IGF-I) in rats of both sexes during pubertal growth spurt and investigated the effects of GHRH deficiency (brought about by neonatal administration of monosodium glutamate, MSG) and exogenous GHRH administration on these parameters. In both sexes, GH mRNA content increased three- to fourfold between 4 and 12 wk of life and declined thereafter toward 33 wk of life. This was accompanied by virtually parallel changes in pituitary GH content and in serum IGF-I. Neonatal MSG abolished the pubertal increases in GH mRNA, pituitary GH, and serum IGF-I and severely impaired growth rate. Exogenous GHRH (25 micrograms/kg sc every 8 h for 7 days) given to intact animals between 6 and 7 wk of life significantly augmented pituitary GH mRNA content but was less effective in MSG-treated rats. We conclude that 1) pubertal growth spurt in both sexes is associated with rising pituitary GH mRNA content; 2) GHRH deficiency abolishes the puberty-associated increase in GH synthesis and secretion and attenuates somatic growth rate; and 3) exogenous GHRH augments GH mRNA content. Thus puberty-associated augmentation of GHRH secretion is an important mechanism of somatic growth.

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Chronic toxicity of low dose monosodium glutamate in albino Wistar rats

BMC Research Notes ◽

10.1186/s13104-019-4611-7 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 3

Author(s):

Josiah Okwudili Nnadozie ◽

Udunma Olive Chijioke ◽

Okechukwu Charles Okafor ◽

Daniel Bankole Olusina ◽

Angus Nnamdi Oli ◽

...

Keyword(s):

Wistar Rats ◽

Low Dose ◽

Monosodium Glutamate ◽

Significant Rise ◽

Female Rats ◽

Fasting Serum ◽

Organ Function ◽

Function Tests ◽

Major Organ ◽

Renal Function Tests

Abstract Objective The objective of this study was to observe the effects of chronic dosing with monosodium glutamate on mortality, fertility, major organ functions and histology in albino Wistar rats. Results 6 male and 6 female rats (age 6 weeks) were bred in a cage, feeding on standard growers’ mash, with monosodium glutamate added (120 mg/kg/day). 12 corresponding breeding rats (on standard feed without MSG) were controls. Chronic dosing with monosodium glutamate in albino Wistar rats (at a dose consistent with the human ADI) led to increased mortality, fertility impairment, and significant changes in major organ function tests and histology. 23 deaths were recorded in the rats fed with MSG additive, while mortality was zero in the control animals. Fertility was lower in rats on MSG (48 births) than in controls (117 births). The weight gain of the MSG rats was higher than in controls. Biochemical parameters and organ histology remained normal in control animals. In MSG-treated rats however, liver/renal function tests, fasting serum cholesterol and triglyceride, serum uric acid showed a significant rise at trimestrial time-points. Histology showed mild portal inflammation in MSG rats, with periglomerular fibrosis and interstitial nephritis in two rats, at 6–12 months.

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Hormonal and Behavioral Characteristics of Prenatally Stressed Female Rats in an Experimental Model of Depression

Neuroscience and Behavioral Physiology ◽

10.1007/s11055-019-00772-6 ◽

2019 ◽

Vol 49 (5) ◽

pp. 573-579

Author(s):

N. E. Ordyan ◽

S. G. Pivina ◽

V. I. Mironova ◽

V. K. Akulova ◽

V. V. Rakitskaya

Keyword(s):

Experimental Model ◽

Female Rats ◽

Behavioral Characteristics ◽

Stressed Female ◽

Prenatally Stressed

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Effects of frovatriptan and almotriptan on locomotor activity in female rats with experimental model of migraine

European Neuropsychopharmacology ◽

10.1016/j.euroneuro.2018.11.423 ◽

2019 ◽

Vol 29 ◽

pp. S266-S267 ◽

Cited By ~ 1

Author(s):

K. Saracheva ◽

L. Vasileva ◽

D. Getova

Keyword(s):

Locomotor Activity ◽

Experimental Model ◽

Female Rats

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

Reproduction ◽

10.1530/rep.0.1210915 ◽

2001 ◽

pp. 915-924 ◽

Cited By ~ 10

Author(s):

L Pinilla ◽

LC Gonzalez ◽

F Gaytan ◽

M Tena-Sempere ◽

E Aguilar

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Body Weight ◽

Oestrogen Receptor ◽

Female Rats ◽

Male Rats ◽

Selective Oestrogen Receptor Modulators ◽

Male And Female Rats ◽

The Central Nervous System ◽

Neonatal Administration

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.

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