Effects of Insulin, Metrazol, and Electroconvulsive Shocks upon Learning to Learn 30 Successive Reversal Problems by Rats

1970 ◽  
Vol 26 (2) ◽  
pp. 551-558 ◽  
Author(s):  
Loh Seng Tsai ◽  
Vernon J. Perez ◽  
Jefferson M. Koonce

To determine the relative effects of insulin, metrazol and electroconvulsive shocks upon learning to learn 30 successive reversal problems by rats, an enclosed square T-maze was used, with water as incentive after 23 hr. of deprivation. S had to achieve 9 correct out of 10 daily trials before a problem was reversed. 40 adult male rats were equally divided into a control and 3 differently shocked groups. Shocks were administered on 3 alternate days followed by 2 days of rest. Each time, Ss of the 4 groups received respectively 0.5 cc. of saline, 55 mg. of metrazol per kg. of body-weight, one unit of insulin per 20 gm. of body-weight, and an electric current of 50 ma. at 25 v for 150 msec. Convulsion in the insulin group was prevented by an injection of dextrose and potassium chloride. The control was significantly superior to the 3 shocked groups which were remarkably similar or practically identical in their performance during the initial 6 problems. Thereafter, both the non-convulsive (saline and insulin) groups did better than the 2 convulsive groups either in terms of error, day, or one-trial reversal score.

1995 ◽  
Vol 268 (4) ◽  
pp. E546-E550 ◽  
Author(s):  
C. N. Boozer ◽  
G. Schoenbach ◽  
R. L. Atkinson

This study examined the effects of increasing levels of dietary fat fed isocalorically on body weight, body composition, and adipose distribution. Adult male rats were weight matched into four groups. One group that was fed a low-fat diet (12%) served as reference controls. The other three groups were fed diets of 24, 36, or 48% fat in amounts to equal the energy intake of the control group. After 6 wk, body weights of the four groups were not significantly different. Intrascapular brown fat did not differ between groups. Total body fat and adipose depot weights, however, increased in proportion to the level of fat in the diet. Total body fat and retroperitoneal and mesenteric depot weights of the 48% fat group were greater than controls (P < 0.05). Mesenteric fat in this group was also significantly increased over all other groups (P < 0.05). These results show that high-fat diets fed to adult animals cause increased body fat in the absence of significant changes in body weight and that mesenteric fat is increased disproportionately.


2000 ◽  
pp. 406-410 ◽  
Author(s):  
M Tena-Sempere ◽  
L Pinilla ◽  
LC Gonzalez ◽  
J Navarro ◽  
C Dieguez ◽  
...  

The obese gene (ob) product, leptin, has recently emerged as a key element in body weight homeostasis, neuroendocrine function and fertility. Identification of biologically active, readily synthesized fragments of the leptin molecule has drawn considerable attention, as they may provide a powerful tool for detailed characterization of the biological actions of leptin in different experimental settings. Recently, a fragment of mouse leptin protein comprising amino acids 116-130, termed leptin(116-130) amide, was shown to mimic the effects of the native molecule in terms of body weight gain and food intake, and to elicit LH and prolactin (PRL) secretion in vivo. As a continuation of our previous experimental work, the present study reports on the effects of leptin(116-130) amide on basal and stimulated testosterone secretion by adult rat testis in vitro. In addition, a comparison of the effects of human recombinant leptin and leptin(116-130) amide at the pituitary level on the patterns of LH, FSH, PRL and GH secretion is presented. As reported previously by our group, human recombinant leptin(10(-9)-10(-7)M) significantly inhibited both basal and human chorionic gonadotrophin (hCG)-stimulated testosterone secretion in vitro. Similarly, incubation of testicular tissue in the presence of increasing concentrations of leptin(116-130) amide (10(-9)-10(-5)M) resulted in a dose-dependent inhibition of basal and hCG-stimulated testosterone secretion; a reduction that was significant from a dose of 10(-7)M upwards. In addition, leptin(116-130) amide, at all doses tested (10(-9)-10(-5)M), significantly decreased LH and FSH secretion by incubated hemi-pituitaries from adult male rats. In contrast, in the same experimental protocol, recombinant leptin(10(-9)-10(-7)M) was ineffective in modulating LH and FSH release. Finally, neither recombinant leptin nor leptin(116-130) amide were able to change basal PRL and GH secretion in vitro. Our results confirm the ability of leptin, acting at the testicular level, to inhibit testosterone secretion, and map the effect to a domain of the leptin molecule that lies between amino acid residues 116 and 130. In addition, we provide evidence for a direct inhibitory action of leptin(116-130) amide on pituitary LH and FSH secretion, a phenomenon not observed for the native leptin molecule, in the adult male rat.


1968 ◽  
Vol 46 (4) ◽  
pp. 697-700 ◽  
Author(s):  
K. Brown-Grant

The changes observed in the metabolism of radioiodide and radiophosphorus by the thyroid gland of intact adult male rats following a single injection of estradiol benzoate (4 μg/100 g body weight) are consistent with the suggestion (F. Labrie, G. Pelletier, and C. Fortier. Federation Proc. 26, 484 (1967). Abstr.) that at this dose level estrogen causes a hypersecretion of TSH in such animals.


2014 ◽  
Vol 11 (1) ◽  
pp. 36 ◽  
Author(s):  
Clare L Adam ◽  
Patricia A Williams ◽  
Matthew J Dalby ◽  
Karen Garden ◽  
Lynn M Thomson ◽  
...  

1977 ◽  
Vol 84 (4) ◽  
pp. 842-849 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes

ABSTRACT Effects of subcutaneous administration of various doses of different steroids on serum levels of LH and FSH in normal, adult male rats were investigated. Each steroid was injected daily during 7 days in doses of 50, 25, 12.5 or 6.25 μg per 100 g body weight. Ring A 5α-reduced testosterone metabolites exerted high activity in suppressing serum LH and FSH levels. 5α-Androstane-3β,17β-diol had in the doses tested, however, no such effects on serum gonadotrophins. Serum LH concentrations in normal rats appeared more sensitive to steroid treatment than serum FSH concentrations.


1987 ◽  
Vol 65 (2) ◽  
pp. 580-582 ◽  
Author(s):  
Loh Seng Tsai

30 adult male white rats were equally divided into control, scopolamine, and electroconvulsive shock groups to learn 20 successive reversal problems in an E-maze for water after 23 ½ hr. of deprivation. The noncorrection method was used. After 1 mo. of preliminary training, each scopolamine animal received an intraperitoneal injection of 1 mgm of scopolamine hydro-bromide per kgm of body weight while each in the shock group was given an ECS of 35 mA for .2 sec. at the end of every 10 daily trials. When a rat obtained 9 correct of 10 trials, the goal was switched to the opposite side of the maze. Controls were much superior to both experimental groups. While scopolamine animals experienced more detrimental effects initially, they caught up with the shock group and finally became superior. This shift is interpreted in terms of building tolerance to scopolamine and increasing anxiety to shock as effects of differential treatments accumulated.


2000 ◽  
pp. 517-523 ◽  
Author(s):  
MA Rol De Lama ◽  
A Perez-Romero ◽  
JA Tresguerres ◽  
M Hermanussen ◽  
C Ariznavarreta

OBJECTIVE: A novel non-invasive technique termed microknemometry, which allows daily leg length measurement, was used to investigate the growth promoting effect of growth hormone (GH) on peripubertal rats. We compared the effect of different patterns of recombinant human (rh) GH administration to peripubertal male rats with the effect produced by two daily administrations of the same amount of rhGH to peripubertal female rats or adult male rats. Another group of peripubertal male rats was also submitted to a 3-day period of starvation, in order to study catch-up growth during refeeding and to determine whether this process could be stimulated by exogenous GH administration. RESULTS: GH treatment was unable to stimulate tibial growth or weight gain in peripubertal males, whereas a clear growth promoting effect was observed in female rats and also in adult male rats. Starvation caused a dramatic body weight loss, and a reduction in tibial growth rate. Peripubertal male rats gained body weight faster than unstarved animals during refeeding, although recovery was not complete after nine days. Tibial growth, however, was resumed at the same speed as in normally fed males. This means that no catch-up effect was observed after refeeding in animals either with or without GH treatment. CONCLUSIONS: During peripuberty, normal male rats grow at a maximal speed that cannot be further increased by exogenous GH treatment, whereas age-matched female rats or older males grow at a slower rate than peripubertal males. Thus, exogenous rhGH administration is capable of enhancing growth velocity.


2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Herrera-Pérez José Jaime ◽  
Benítez-Coronel Venus ◽  
Jiménez-Rubio Graciela ◽  
Hernández-Hernández Olivia Tania ◽  
Martínez-Mota Lucía

In a previous study, we found that chronic mild stress (CMS) paradigm did not induce anhedonia in young-adult male rats but it reduced their body weight gain. These contrasting results encouraged us to explore other indicators of animal’s vulnerability to stress such as anxious-like behaviors, since stress is an etiologic factor also for anxiety. Thus, in this study, we evaluated the vulnerability of these animals to CMS using behavioral tests of depression or anxiety and measuring serum corticosterone. Male Wistar rats were exposed to four weeks of CMS; the animals’ body weight and sucrose preference (indicator of anhedonia) were assessed after three weeks, and, after the fourth week, some animals were evaluated in a behavioral battery (elevated plus maze, defensive burying behavior, and forced swimming tests); meanwhile, others were used to measure serum corticosterone. We found that CMS (1) did not affect sucrose preference, immobility behavior in the forced swimming test, or serum corticosterone; (2) decreased body weight gain; and (3) increased the rat’s entries into closed arms of the plus maze and the cumulative burying behavior. These data indicate that young male rats’ vulnerability to CMS is reflected as poor body weight gain and anxious-like instead of depressive-like behaviors.


1977 ◽  
Vol 37 (2) ◽  
pp. 259-268 ◽  
Author(s):  
R. J. Neale ◽  
J. C. Waterlow

1. The fractional rate of loss of 14C and body-weight was measured in adult male rats after giving 14C-labelled methionine or leucine and maintaining rats for 30 d on a low-protein or a specific methionine+cystine-free diet: carcasses were then analysed for protein and fat 14C radioactivity.2. The fractional loss of 14CO2 from [14C]methionine or [14C]leucine between day 20 and day 30 was always greater than the fractional loss of body-weight.3. Carcass protein 14C radioactivity after giving [14C]leucine was higher than after giving [14C]methionine, but fat 14C radioactivity after either 14C-labelled amino acid was only a small proportion of the total body 14C radioactivity.4. After correction of the fractional loss of 14CO2 for urinary 14C loss, but not body-weight loss, absolute amino acid loss was calculated using published values for methionine and leucine content of rats.5. The best estimates of endogenous amino acid loss obtained using 1-14C-labelled amino acids, expressed as mg/kg body-weight0.75 per day were leucine 79, methionine 38.


1990 ◽  
Vol 126 (3) ◽  
pp. 431-435 ◽  
Author(s):  
H. Mandal ◽  
P. K. Ghosh ◽  
N. M. Biswas

ABSTRACT Adult male rats were given s.c. injections of melatonin (400 μg/100 g body weight per day) for 14 days. On day 15, the weights of the testis and accessory sex organs were less, testicular 17β-hydroxysteroid dehydrogenase (17β-HSD) activity was inhibited, spermatogenesis was suppressed and serum levels of gonadotrophins, testosterone and α2u-globulin were decreased compared with control animals injected with vehicle. In a third group of rats given the same dose of melatonin for 14 days, administration of dihydrotestosterone (DHT) at a dose of 25 μg/100 g body weight per day on days 8–14 resulted in serum levels of α2u-globulin, FSH, LH and testosterone and testicular 17β-HSD activity similar to those seen in vehicle-injected control animals. Weights of the testes and accessory sex organs and spermatogenesis were normal after administration of DHT in melatonintreated rats. In another group of rats, the depressive effects of melatonin treatment on plasma gonadotrophins were reversed by the administration of α2u-globulin on days 8–14. It was concluded that treatment with DHT prevents the depressive action of melatonin on testicular function by inducing the synthesis of α2u-globulin. Journal of Endocrinology (1990) 126, 431–435


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