Posterodorsal Medial Amygdala Mediates Tail‐Pinch Induced Food Intake in Female Rats

Background: Obesity is because of excessive fat accumulation that affects health adversely in the form of various diseases such as diabetes, hypertension, cardiovascular diseases, and many other disorders. Our Indian diet is rich in carbohydrates, and hence the sucrose-induced obesity is an apt model to mimic this. Ventromedial hypothalamus (VMH) is linked to the regulation of food intake in animals as well as humans. Purpose: To understand the role of VMHin sucrose-induced obesity on metabolic parameters. Methods: A total of 24 adult rats were made obese by feeding them on a 32% sucrose solution for 10 weeks. The VMH nucleus was ablated in the experimental group and sham lesions were made in the control group. Food intake, body weight, and biochemical parameters were compared before and after the lesion. Results: Male rats had a significant weight gain along with hyperphagia, whereas female rats did not have a significant weight gain inspite of hyperphagia. Insulin resistance and dyslipidemia were seen in both the experimental and control groups. Conclusion: A sucrose diet produces obesity which is similar to the metabolic syndrome with insulin resistance and dyslipidemia, and a VMH lesion further exaggerates it. Males are more prone to this exaggeration.

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The anorectic effect of fenfluramine is influenced by sex and stage of the estrous cycle in rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00779.2004 ◽

2005 ◽

Vol 288 (6) ◽

pp. R1486-R1491 ◽

Cited By ~ 24

Author(s):

Lisa A. Eckel ◽

Heidi M. Rivera ◽

Deann P. D. Atchley

Keyword(s):

Food Intake ◽

Estrous Cycle ◽

Female Rats ◽

Male Rats ◽

Gonadal Hormone ◽

Estrous Female ◽

Male And Female Rats ◽

Daily Food ◽

Hormone Status ◽

Anorectic Effect

The controls of food intake differ in male and female rats. Daily food intake is typically greater in male rats, relative to female rats, and a decrease in food intake, coincident with the estrous stage of the ovarian reproductive cycle, is well documented in female rats. This estrous-related decrease in food intake has been attributed to a transient increase in the female rat's sensitivity to satiety signals generated during feeding bouts. Here, we investigated whether sex or stage of the estrous cycle modulate the satiety signal generated by fenfluramine, a potent serotonin (5-HT) releasing agent. To examine this hypothesis, food intake was monitored in male, diestrous female, and estrous female rats after intraperitoneal injections of 0, 0.25, and 1.0 mg/kg d-fenfluramine. The lower dose of fenfluramine decreased food intake only in diestrous and estrous females, suggesting that the minimally effective anorectic dose of fenfluramine is lower in female rats, relative to male rats. Although the larger dose of fenfluramine decreased food intake in both sexes, the duration of anorexia was greater in diestrous and estrous female rats, relative to male rats. Moreover, the magnitude of the anorectic effect of the larger dose of fenfluramine was greatest in estrous rats, intermediate in diestrous rats, and least in male rats. Thus our findings indicate that the anorectic effect of fenfluramine is modulated by gonadal hormone status.

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Prolactin stimulates food intake in a dose-dependent manner

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1989.256.1.r276 ◽

1989 ◽

Vol 256 (1) ◽

pp. R276-R280 ◽

Cited By ~ 6

Author(s):

T. Gerardo-Gettens ◽

B. J. Moore ◽

J. S. Stern ◽

B. A. Horwitz

Keyword(s):

Food Intake ◽

Female Rats ◽

High Dose ◽

Dependent Manner ◽

Additional Control ◽

The Mean ◽

Ovine Prolactin ◽

Dose Dependent ◽

Medium Dose ◽

Cumulative Food Intake

Lactation in the rat is marked by pronounced hyperphagia and suppression of brown fat (BAT) thermogenic capacity. We previously examined the possibility that elevated prolactin levels mediate these changes. The present study evaluated the effect of varying prolactin levels on food intake, BAT mitochondrial GDP binding, and carcass adiposity. Female rats were injected daily for 10 days with ovine prolactin at one of three doses: high = 3.0, medium = 1.0, or low = 0.3 micrograms/g body wt. Controls were injected with 0.9% NaCl. A group of uninjected rats served as an additional control. Cumulative food intake was significantly elevated in a dose-dependent manner in the prolactin-treated animals relative to the saline-injected and uninjected controls. Compared with the saline controls, the mean cumulative food intake was greatest at the high dose (20% increase), intermediate at the medium dose (17%), and smallest at the low dose (12%). Prolactin-treated rats gained significantly more weight during the experiment than did controls. Despite the hyperphagia in the prolactin-treated rats, no significant differences in BAT mitochondrial GDP binding were observed among the five groups. These data indicate that elevated prolactin levels stimulate food intake in a dose-dependent manner and that this hyperphagia is not accompanied by an increase in BAT mitochondrial GDP binding.

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Effect of (-)-hydroxycitrate on development of obesity in the Zucker obese rat

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1981.240.1.e72 ◽

1981 ◽

Vol 240 (1) ◽

pp. E72-E78 ◽

Cited By ~ 5

Author(s):

M. R. Greenwood ◽

M. P. Cleary ◽

R. Gruen ◽

D. Blase ◽

J. S. Stern ◽

...

Keyword(s):

Body Weight ◽

Food Intake ◽

Cell Size ◽

Treatment Period ◽

Body Fat ◽

Substantial Reduction ◽

Female Rats ◽

Fat Cell ◽

Fat Cell Size ◽

Obese Rats

Young Zucker lean (Fa/-) and obese (fa/fa) female rats were fed the fatty acid synthesis inhibitor (-)-hydroxy-citrate as a dietary admixture for 39 days. In the lean rats, (-)-hydroxycitrate treatment decreased body weight, food intake, percent of body fat, and fat cell size. In the obese rat, food intake and body weight were reduced but the percent of body fat remained unchanged. Throughout the treatment period, obese rats maintained a fat cell size equivalent to their obese controls. Although a reduction in fat cell number in the obese rats occurred during the treatment period, marked hyperplasia was observed during the posttreatment period. The results of this study indicate that the obese rat, despite a substantial reduction in body weight produced by (-)-hydroxycitrate, still defends its obese body composition.

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BODY WEIGHT AND FOOD CONSUMPTION OF LACTATING RATS NURSING VARIOUS SIZES OF LITTERS

Journal of Endocrinology ◽

10.1677/joe.0.0380263 ◽

1967 ◽

Vol 38 (3) ◽

pp. 263-268 ◽

Cited By ~ 52

Author(s):

K. ÔTA ◽

A. YOKOYAMA

Keyword(s):

Body Weight ◽

Food Intake ◽

Food Consumption ◽

Ovarian Function ◽

Experimental Period ◽

Close Correlation ◽

Female Rats ◽

Linear Relationships ◽

Rate Of Increase ◽

Daily Gain

SUMMARY Changes in body weight and food consumption during lactation in rats nursing various sizes of litters were studied. The rate of increase in body weight of the mother rats during the experimental period (day 3–14 of lactation) was very similar in mothers with different numbers (2, 4, 8 and 12) of suckling pups/litter. It is suggested that the weight increase of adult female rats during lactation is related more closely to the alteration of ovarian function caused by the suckling stimulus than to the enhanced food intake during this period. Both the food intake of mother rats and the daily gain in weight of litters increased as the number of suckling pups/litter increased and as lactation advanced. Linear relationships were observed between the logarithm of the litter size and both the food intake of the mother rats and the weight gain of the litters. The presence of a close correlation between the food intake of mother rats and the quantity of milk produced by them is suggested.

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Impeded Eruption Rate of the Rat Maxillary Incisor During Exposure to Different Simulated Altitudes

Journal of Dental Research ◽

10.1177/00220345870660091501 ◽

1987 ◽

Vol 66 (9) ◽

pp. 1490-1492 ◽

Cited By ~ 6

Author(s):

M.J. Giglio ◽

A.M. Sanz ◽

A. Constanzo ◽

C.E. Bozzini

Keyword(s):

Body Weight ◽

Food Intake ◽

Sea Level ◽

Body Length ◽

Conclusive Evidence ◽

Female Rats ◽

Maxillary Incisor ◽

Eruption Rate ◽

Insight Into

Female rats weighing about 200 g each were separated into normoxic and hypoxic groups. The former were maintained at sea-level conditions. The hypoxic groups were placed in an altitude chamber and maintained at the equivalent of 1850 m, 4100 m, or 7100 m over a period of two weeks. Hematocrit, body weight, body length, and impeded eruption rate were recorded once a week. Food intake was recorded every day. Exposure to 1850 m did not significantly alter hematocrit, body weight and body length gains, food intake, and impeded eruption rate. Nevertheless, exposure to 4100 m and 7100 m decreased body weight and body length gains, food intake, and impeded eruption rate, and increased hematocrit value. These parameters varied as a function of altitude. In spite of the lack of conclusive evidence, this work affords further insight into the particular significance of polycythemia on the eruption rate.

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Excitotoxic Amino Acid Injections into the Medial Amygdala Facilitate Maternal Behavior in Virgin Female Rats

Hormones and Behavior ◽

10.1006/hbeh.1993.1005 ◽

1993 ◽

Vol 27 (1) ◽

pp. 56-81 ◽

Cited By ~ 72

Author(s):

Michael Numan ◽

Marilyn J. Numan ◽

Jeffrey B. English

Keyword(s):

Amino Acid ◽

Maternal Behavior ◽

Virgin Female ◽

Female Rats ◽

Medial Amygdala

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Effects of intragastric hyperalimentation on pair-fed rats with ventromedial hypothalamic lesions

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1985.248.2.r172 ◽

1985 ◽

Vol 248 (2) ◽

pp. R172-R180

Author(s):

M. C. Walgren ◽

T. L. Powley

Keyword(s):

Food Intake ◽

Energy Utilization ◽

Female Rats ◽

Metabolic Responses ◽

Compensatory Strategy ◽

The Face ◽

Energy Retention ◽

Identical Number ◽

Reducing Energy ◽

Intact Rats

The present study was undertaken to determine the relative contributions of altered metabolic responses and excess food intake to the obesity and hyperinsulinemia of the ventromedial hypothalamic (VMH) syndrome. This experiment, employing an intragastric hyperalimentation protocol, was also designed to address the related issue of whether altered energy utilization serves as a compensatory strategy for reducing energy retention in the face of excess intake. Separate groups of VMH-lesioned and sham-lesioned female rats were fed, either orally or intragastrically, up to 200% of the calories ingested by a normally feeding intact rat. Both VMH-lesioned and intact rats became obese and hyperinsulinemic when hyperalimented for 30 days, but rats with lesions deposited 25% more fat than intact animals receiving an identical number of calories. Estimates of total carcass energy indicated that rats with lesions required 11% less calories than intact rats to retain identical levels of energy. Furthermore, intact hyperalimented rats failed to evidence the caloric wastage that has been reported to occur in orally fed rats that overeat cafeteria diets.

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