PHOSPHORUS METABOLISM IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 2209-2214
Author(s):  
John R. Beaton

Male rats weighing 207 ± 2.38 g were exposed to cold (2–3 °C) for a period of 7 days during which urine and faeces were collected daily and analyzed for phosphorus. As a consequence of cold exposure, urinary excretion of phosphorus is increased. With free access to food, the increased food (and hence phosphorus) intake of the animals compensates for the increased urinary excretion and a normal phosphorus balance results. Cold exposure was without significant effect upon blood concentrations of acid-soluble, inorganic, organic, or lipid phosphorus. Increased inorganic and decreased organic, non-lipid phosphorus levels were observed in livers of cold-exposed rats. These observations suggest the breakdown of organic phosphates (e.g. hexose and triose phosphates, adenosine phosphates, phosphocreatine) to inorganic phosphorus.


1963 ◽  
Vol 41 (11) ◽  
pp. 2209-2214 ◽  
Author(s):  
John R. Beaton

Male rats weighing 207 ± 2.38 g were exposed to cold (2–3 °C) for a period of 7 days during which urine and faeces were collected daily and analyzed for phosphorus. As a consequence of cold exposure, urinary excretion of phosphorus is increased. With free access to food, the increased food (and hence phosphorus) intake of the animals compensates for the increased urinary excretion and a normal phosphorus balance results. Cold exposure was without significant effect upon blood concentrations of acid-soluble, inorganic, organic, or lipid phosphorus. Increased inorganic and decreased organic, non-lipid phosphorus levels were observed in livers of cold-exposed rats. These observations suggest the breakdown of organic phosphates (e.g. hexose and triose phosphates, adenosine phosphates, phosphocreatine) to inorganic phosphorus.



1959 ◽  
Vol 196 (5) ◽  
pp. 965-968 ◽  
Author(s):  
Clarence Cohn ◽  
Dorothy Joseph

Normal young adult male rats were either force-fed or allowed to eat ad libitum a moderate carbohydrate diet for 3–4 weeks. The force-fed animals were given either the amount of diet consumed by the animals eating ad libitum (pair-fed) or 80% of this amount (underfed). After a 2-week period of observation, we found that the rats eating ad libitum gained 65 gm of body weight, the pair-fed, force-fed 62 gm and the underfed, force-fed 40 gm. On the basis of the water, fat and protein content of the skin, viscera and carcass of control animals killed at the beginning of the feeding regimen and of similar constituents of the experimental animals after 2 weeks of feeding, the composition of the newly formed tissues of the various groups of animals consisted of the following: a) the rat with free access to food—water = 67.8%, fat = 7.8% and protein = 22.4%; b) the pair-fed, force-fed animal—water = 55.5%, fat = 23.6% and protein = 17.7%; c) the underfed, force-fed animal—water = 64.4%, fat = 7.9% and protein = 20.0%. The ratio of calories retained in newly formed tissue to the calories ingested over the 2-week period was 11.9% for the animals eating ad libitum, 20.6% for the pair-fed, force-fed animals and 9.5% for the underfed, force-fed rats. Force feeding appears to change intermediary metabolic pathways in the direction of increased ‘efficiency’ with resultant greater fat deposition.



1969 ◽  
Vol 9 (36) ◽  
pp. 63
Author(s):  
RJW Gartner ◽  
JG Morris ◽  
Patricia M Pepper

The concentrations of urea, inorganic phosphorus, haemoglobin, plasma chloride, sodium, and potassium and the packed cell volume were determined on samples of blood from 70 Hereford steers that had been intensively finished on high-grain rations based on either wheat, barley, or sorghum grain. Oaten chaff was used as the roughage and half the steers had free access to sodium chloride. The inorganic phosphorus levels of 6.5 to 7.1 mg/100 m1 of blood were higher than those recorded in grazing cattle and were significantly different for the grain types. Blood urea levels were affected by roughage level, grain types, and access to sodium chloride. Plasma sodium but not chloride was affected by the type of grain and by sodium chloride.



2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jay H. Williams ◽  
Timothy W. Batts ◽  
Simon Lees

This investigation examined the effects of reduced muscle glycogen on exercise performance and muscle fatigue. Male rats were assigned to a low glycogen group (LG) that participated in a protocol of exercise and fasting, a high glycogen group (HG) that exercised but were allowed free access to food, or control group (CON) that did not exercise but were allowed free access to food. Following the protocol, muscle glycogen content of the LG animals was reduced by 45%. The LG animals also performed 79 and 81% less voluntary treadmill exercise than the HG and CON groups. At exhaustion, the LG group had lower blood glucose than HG and CON but exhibited no reduction in sarcoplasmic reticulum (SR) function. During 30 min of in situ stimulation, the rates and magnitudes of muscle fatigue were not significantly different between groups, and fatigue-induced reductions in SR function were similar between groups. The results indicate that reduced muscle glycogen markedly impairs voluntary exercise performance but does not appreciably affect isolated muscle function. It is likely that exercise exhaustion due to reduced muscle glycogen is due, in large part, to hypoglycemia and central fatigue as opposed to peripheral mechanisms.



2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
A. O. Ibitayo ◽  
O. B. Afolabi ◽  
A. J. Akinyemi ◽  
T. I. Ojiezeh ◽  
K. O. Adekoya ◽  
...  

The advent of Wi-Fi connected high technology devices in executing day-to-day activities is fast evolving especially in developing countries of the world and hence the need to assess its safety among others. The present study was conducted to investigate the injurious effect of radiofrequency emissions from installed Wi-Fi devices in brains of young male rats. Animals were divided into four equal groups; group 1 served as control while groups 2, 3, and 4 were exposed to 2.5 Ghz at intervals of 30, 45, and 60 consecutive days with free access to food and water ad libitum. Alterations in harvested brain tissues were confirmed by histopathological analyses which showed vascular congestion and DNA damage in the brain was assayed using agarose gel electrophoresis. Histomorphometry analyses of their brain tissues showed perivascular congestion and tissue damage as well.



1949 ◽  
Vol 27e (3) ◽  
pp. 202-209 ◽  
Author(s):  
Jules Tuba ◽  
Donald B. Baker ◽  
Max M. Cantor

Castration produces a fall in serum inorganic phosphorus values in adult male rats but not in adult female rats. The alterations of phosphorus levels that occur following castration in male rats and after the injection of some hormones into normal and castrated rats of both sexes may be accounted for by corresponding alterations in metabolic requirements. Neither castration nor hormone injection produces any significant change in serum acid phosphatase activity in male or in female rats. A fall of about 30% to levels approaching values for normal female rats is found in serum alkaline phosphatase of castrated male rats in about eight weeks. There is no change in the enzyme values in castrated females. In those instances where injections of a sex hormone into castrated or normal rats produce alterations in alkaline serum phosphatase values such changes may be accounted for on the basis of altered food intake. The sole exception to this finding is the very marked decrease in the activity of the enzyme produced by progesterone after oestrogen in normal male rats.



2003 ◽  
Vol 285 (5) ◽  
pp. R1055-R1065 ◽  
Author(s):  
John D. Wilson ◽  
Danielle M. Nicklous ◽  
Vincent J. Aloyo ◽  
Kenny J. Simansky

The pontine parabrachial nucleus (PBN) has been implicated in regulating ingestion and contains opioids that promote feeding elsewhere in the brain. We tested the actions of the selective μ-opioid receptor (μ-OR) agonist [d-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (DAMGO) in the PBN on feeding in male rats with free access to food. Infusing DAMGO (0.5-4.0 nmol/0.5 μl) into the lateral parabrachial region (LPBN) increased food intake. The hyperphagic effect was anatomically specific to infusions within the LPBN, dose and time related, and selective for ingestion of chow compared with (nonnutritive) kaolin. The nonselective opioid antagonist naloxone (0.1-10.0 nmol intra-PBN) antagonized DAMGO-induced feeding, with complete blockade by 1.0 nmol and no effect on baseline. The highly selective μ-opioid antagonist d-Phe-Cys-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP; 1.0 nmol) also prevented this action of DAMGO, but the κ-antagonist nor-binaltorphimine did not. Naloxone and CTAP (10.0 nmol) decreased intake during scheduled feeding. Thus stimulating μ-ORs in the LPBN increases feeding, whereas antagonizing these sites inhibits feeding. Together, our results implicate μ-ORs in the LPBN in the normal regulation of food intake.



1961 ◽  
Vol 39 (8) ◽  
pp. 1267-1275 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme

Further observations on the increase in blood levels of inorganic phosphorus and lactic acid in hypothermic rats are reported. Progressive increase in blood inorganic phosphorus levels with continued cooling to a rectal temperature of 5 °C appears to be a consequence of catabolism of organic, non-lipid phosphorus. With continued cooling, blood lactic acid is progressively increased; liver lactic acid increases initially, returning, at 5 °C, to control values; muscle lactic acid increases initially and thereafter remains relatively constant. Progressive increases in blood levels of inorganic phosphorus and lactic acid with continued cooling appear to be related to the depth, rather than duration, of hypothermia. Rewarming hypothermic (15 °C) rats to 37 °C rectal temperature with artificial ventilation reduces lactic acid levels of blood, liver, and muscle to less than control values. Rewarming alone was found to reduce blood lactic acid levels to less than control values. Elevation of blood lactic acid levels consequent upon hypothermia was prevented by provision of oxygen during cooling but not by pentobarbital anesthesia. These observations are consistent with the hypothesis that, in the hypothermic rat, the available oxygen is insufficient to meet even the reduced metabolic requirements.



Author(s):  
А.С. Казицкая ◽  
Т.К. Ядыкина ◽  
М.С. Бугаева ◽  
А.Г. Жукова ◽  
Н.Н. Михайлова ◽  
...  

В условиях непрерывного воздействия неблагоприятных факторов окружающей и производственной среды на человека особую актуальность приобретает изучение механизмов, поддерживающих гомеостаз организма. Длительное поступление фторидов в организм приводит к формированию хронической фтористой интоксикации, патогенез которой вызывает многочисленные споры и дискуссии. До сих пор недостаточно внимания уделяется изучению висцеральной патологии, обусловленной нарушениями иммунного статуса в условиях воздействия на организм соединений фтора. Практически отсутствуют исследования по изучению иммунной реактивности, определяющей морфофункциональный характер ответной реакции печени на ранних стадиях развития фтористой интоксикации. Цель работы - изучение действий патофизиологических механизмов иммунной реактивности печени при субхроническом действии на организм соединений фтора. Методика. Опыты проведены на 210 лабораторных крысах-самцах массой 180-220 г., разделенных на 2 группы: контрольную (n=80) и группу животных с субхроническим действием фторида натрия (n=130). Экспериментальные животные в течение 12 нед имели свободный доступ к водному раствору фторида натрия (концентрация 10 мг/л, что составляет суточную дозу фтора 1,2 мг/кг массы тела). Для изучения иммунологических и биохимических показателей забирали кровь из хвостовой вены через 1, 3, 6, 9, 12 нед от начала эксперимента. Для оценки состояния гуморального звена иммунитета определяли уровень сывороточных иммуноглобулинов (IgA, IgG, IgM) иммуноферментным анализом с помощью наборов реактивов ЗАО «Вектор-Бест» (Новосибирск). Уровень сывороточных цитокинов: TNF-α, IL-1β, 2, 4, 6, 10 определяли на анализаторе Multiskan EX методом иммуноферментного анализа с использованием наборов «Вектор Бест» (Новосибирск). Подсчет общего количества лейкоцитов произведен классическим способом в камере Горяева, анализ лейкоцитарной формулы - в окрашенных мазках периферической крови. Метаболические изменения оценивали по активности ферментов в ткани печени: щелочной фосфатазы (ЩФ), аланин- и аспартатаминотрансфераз (АЛТ, АСТ), лактатдегидрогеназы (ЛДГ), гаммаглутамилтранспептидазы (γ-ГТ). Активность ферментов определяли унифицированными методами с помощью наборов реактивов ЗАО «Вектор-Бест» (Новосибирск) на фотометре PM-750 (Германия). Гистологические исследования печени осуществляли после декапитации крыс, проводимой под эфирным наркозом. Результаты. Показано, что субхроническое воздействие фторида натрия сопровождается формированием внутриклеточных и внутрисосудистых повреждений печени. Активация медиаторов воспаления и развитие иммунологических нарушений в динамике эксперимента способствуют формированию системной воспалительной реакции, которая приводит к появлению стойких морфологических нарушений в печени и изменению активности ферментов основных метаболических путей. Заключение. Полученные результаты могут быть использованы при разработке и проведении профилактических мероприятий в условиях воздействия на организм высоких концентраций фтора с последовательным применением детоксикационной, иммуномодуляторной и органопротекторной коррекции. Studying mechanisms, which maintain the body homeostasis, is particularly important in the conditions of continuous impact of adverse environmental and manufacturing factors. Long-term exposure to fluorides leads to chronic fluoric intoxication, the pathogenesis of which is a subject of multiple controversy and discussions. Not enough attention is still paid to elucidating the visceral pathology associated with fluorine-induced immune disorders. There are virtually no studies of immune reactions that define the morphofunctional nature of the liver response to early stages of fluoric intoxication. Aim. To study pathophysiological mechanisms of hepatic immune reactivity in subchronic exposure of the body to fluorine compounds. Methods. Experiments were performed on 210 male rats weighing 180-220 g. The animals were divided into two groups: 1) control (n=80) and 2) subchronic exposure to sodium fluoride (n=130). The rats had free access to a 10 mg/l aqueous solution of sodium fluoride (daily dose, 1.2 mg/kg body weight) for 12 weeks. Blood was withdrawn from the caudal vein at 1, 3, 6, 9, and 12 weeks of the experiment for immunological and biochemical tests. Histological study of the liver was performed after decapitation of rats under ether anesthesia. Results. The subchronic exposure to sodium fluoride was associated with intracellular and intravascular damage of the liver. Activation of inflammatory mediators and development of immunological disorders during the experiment contributed to a systemic inflammatory reaction, which resulted in persistent morphological injuries of the liver and changes in enzyme activities in major metabolic pathways. Conclusion. The study results can be used for development and implementation of preventive measures against the effects of high fluorine concentrations, which would include a successive use of detoxification, immunomodulation and organ protection.



Author(s):  
Ewa Zwierzyńska ◽  
Agata Krupa-Burtnik ◽  
Bogusława Pietrzak

Abstract Background Retigabine belongs to the novel generation of antiepileptic drugs but its complex mechanism of action causes that the drug might be effective in other diseases, for instance, alcohol dependence. It is known that ethanol abuse impaired the function of brain structures associated with memory and learning such as the hippocampus. In our previous study, retigabine reduced hippocampal changes induced by ethanol in the EEG rhythms in rabbits. This study is focused on the impact of retigabine on memory processes in male rats receiving alcohol. Methods Memory was evaluated in various experimental models: Morris water maze, Contextual, and Cued Fear Conditioning tests. Retigabine was administered for 3 weeks directly to the stomach via oral gavage at a dose of 10 mg/kg. Rats received also 20% ethanol (5 g/kg/day in two doses) via oral gavage for 3 weeks and had free access to 5% ethanol in the afternoon and at night. Morris water maze was performed after 1 and 3 weeks of ethanol administration and after 1 week from the discontinuation of ethanol administration. Contextual and Cued Fear Conditioning tests were carried out after 24 h and 72 h of alcohol discontinuation. Results The drug significantly decreased ethanol-induced memory disturbances during alcohol administration as well as slightly improved learning processes after the discontinuation of ethanol administration. Conclusions This beneficial effect of retigabine-ethanol interaction on memory may be a relevant element of the drug’s impact on the development of addiction.



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