Effects of cold exposure on inhibition by isoproterenol of release of alanine in the rat

1988 ◽  
Vol 64 (3) ◽  
pp. 906-912 ◽  
Author(s):  
T. Yamada ◽  
M. Shiota ◽  
T. Sugano
Keyword(s):  
Cold Exposure ◽  
Complex Medium ◽  
Control Group ◽  
Bicarbonate Buffer ◽  
Exposure To Cold ◽  
Flow Through

The effects of isoproterenol on the release of alanine during perfusion with pyruvate and valine were studied in perfused hindlimbs from rats that had been kept for 5 or 20 days at 4 degrees C. In hindlimbs perfused with Krebs bicarbonate buffer in a flow-through mode, the rate of release of alanine during perfusion with 2 mM pyruvate plus 5 mM valine was 250 nmol.min-1.leg-1, a rate that is comparable with that reported in hindlimbs perfused with complex medium. Neither the pyruvate-stimulated nor valine plus pyruvate-stimulated rates of release of alanine changed after 20 days of exposure to cold. Isoproterenol inhibited the release of alanine during perfusion with pyruvate, with valine, and with valine plus pyruvate in hindlimbs from a control group of rats. However, in hindlimbs from cold-exposed groups, isoproterenol failed to inhibit the release of alanine during perfusion with valine plus pyruvate and stimulated the release of alanine during perfusion with valine. Aminooxyacetate inhibited the effects of valine, pyruvate, and isoproterenol. The results obtained suggested that cold exposure decreases the responses to isoproterenol of the mechanism of alanine release and causes an increased supply of alanine to the liver.

Tolerance of estrogen-treated rats to acute cold exposure

1979 ◽  
Vol 47 (1) ◽  
pp. 59-66 ◽  
Author(s):  
M. J. Fregly ◽  
D. L. Kelleher ◽  
D. J. Black
Keyword(s):  
Oxygen Consumption ◽  
Cold Exposure ◽  
Previous Experiment ◽  
Female Rats ◽  
Control Group ◽  
Maximal Rate ◽  
Acute Cold Exposure ◽  
Exposure To Cold ◽  
Rate Of Oxygen Consumption ◽  
Rate Of Cooling

Female rats treated chronically with ethynylestradiol (36 micrograms/kg per day) alone, and in combination with the progestational agent, norethynodrel (253 micrograms/kg per day), cooled significantly faster than controls when lightly restrained and exposed to air at 5 degrees C. Rate of cooling of rats given only norethynodrel was similar to that of the control group. In other studies, rate of oxygen consumption was determined for all groups during acute exposure to cold (14 degrees C). All estrogen-treated groups achieved the same maximal rate of oxygen consumption as control and norethynodrel-treated groups during cold exposure, but cooled significantly faster. Two groups of female rats were treated chronically with ethynylestradiol at two separate doses (36 and 61 micrograms/kg per day). An untreated group served as controls. Rate of oxygen consumption of all animals were measured during restraint and exposure to cold (18 degrees C). The estrogen-treated groups again achieved the same maximal rate of oxygen consumption as the control group, but also cooled significantly faster despite the fact that the cold stress was less severe than in the previous experiment. That estrogen-treated rats cooled faster than controls in both studies despite achieving a maximal rate of heat production which did not differ from controls suggests that reduced cold tolerance of estrogen-treated rats may be related to increased heat loss.

scholarly journals Osteocyte Apoptosis Contributes to Cold Exposure-induced Bone Loss

2021 ◽  
Vol 9 ◽  
Author(s):  
Jingke Du ◽  
Zihao He ◽  
Junqi Cui ◽  
Hanjun Li ◽  
Mingming Xu ◽  
...  
Keyword(s):  
Bone Mass ◽  
Bone Remodeling ◽  
Cold Exposure ◽  
Volume Fraction ◽  
Cold Temperature ◽  
Brown Adipocyte ◽  
Control Group ◽  
Dependent Manner ◽  
Bone Volume Fraction ◽  
Exposure To Cold

Emerging evidence indicates that bone mass is regulated by systemic energy balance. Temperature variations have profound effects on energy metabolism in animals, which will affect bone remodeling. But the mechanism remains unclear. 2-month-old C57BL/6J male mice were exposed to cold (4°C) and normal (23°C) temperatures for 28 days and the effects of cold exposure on bone mass was investigated. Micro-computed tomography results showed that bone volume fraction was significantly reduced after 14 days of exposure to cold temperature, and it was recovered after 28 days. Ploton silver staining and immunohistochemical results further revealed that exposure to cold decreased canalicular length, number of E11-and MMP13-positive osteocytes after 14 days, but they returned to the baseline levels after 28 days, different from the normal temperature control group. In addition, change of Caspase-3 indicated that exposure to cold temperature augmented apoptosis of osteocytes. In vitro results confirmed the positive effect of brown adipocytes on osteocyte‘s dendrites and E11 expression. In conclusion, our findings indicate that cold exposure can influence bone mass in a time-dependent manner, with bone mass decreasing and recovering at 2 and 4 weeks respectively. The change of bone mass may be caused by the apoptosis osteocytes. Brown adipocyte tissue could influence bone remodeling through affecting osteocyte.

Effect of different substrates on survival and growth of juveniles of the freshwater narrow-clawed crayfish Astacus leptodactylus Eschscholtz, 1823 (Decapoda, Astacidae)

Crustaceana ◽  
2017 ◽  
Vol 90 (11-12) ◽  
pp. 1289-1302 ◽  
Author(s):  
Yavuz Mazlum ◽  
Ozlem Guner Gurlek ◽  
Sinem Sirin
Keyword(s):  
Survival Rate ◽  
Treatment Group ◽  
Total Yield ◽  
Control Group ◽  
Astacus Leptodactylus ◽  
Growth Increase ◽  
Key Factor ◽  
Flow Through ◽  
Survival And Growth ◽  
Intermediate Value

Substrate is a key factor for successful crayfish culture, and it can be used to increase the survival rate. The effects of substrate on the survival and growth ofAstacus leptodactylusEschscholtz, 1823 were evaluated in flow-through compartments, divided into three sections and with two different substrates, over a period of 90 days. The three treatments used in the study were: artificial ropes, small stones, and a control group that received no substrate. The survival rate was highest in the small-stones treatment group (77.3%) and was lowest in the without-substrate treatment group (41.3%), while the artificial-ropes group showed an intermediate value (65.3%). Total yield was lower in the control group, 22.46% (25.0 g) as compared to the small-stones treatment group, with 42.3% (51.3 g) and the artificial-ropes treatment with 35.51% (55.8 g). In addition, cheliped injuries were found in higher proportion in the group without cover, and the artificial ropes yielded better results compared to the small-stones and no-substrate group in regard of the growth-increase rate.

EFFECT OF THE EXPOSURE TO COLD ON THE EXTRATHYROIDAL CONVERSION OF L-THYROXINE TO TRIIODO-L-THYRONINE, AND ON INTRAMITOCHONDRIAL α-GLYCEROPHOSPHATE DEHYDROGENASE ACTIVITY IN THYROIDECTOMIZED RATS ON L-THYROXINE

1975 ◽  
Vol 78 (3) ◽  
pp. 481-492 ◽  
Author(s):  
J. Bernal ◽  
F. Escobar del Rey
Keyword(s):  
Dehydrogenase Activity ◽  
Paper Chromatography ◽  
Cold Exposure ◽  
Isotopic Equilibrium ◽  
Glycerophosphate Dehydrogenase ◽  
Exposure To Cold ◽  
Constant Dose ◽  
And Control

ABSTRACT Thyroidectomized rats have been injected daily with 125I labelled L-thyroxine (T4*) and, once isotopic equilibrium was attained, divided into cold-exposed (4–10°C) and control (21–24°C) groups, the daily T4* administration being continued till the end of the experiment. Fourteen days after onset of cold exposure, the total I* of different organs and of the carcass was determined and the tissues submitted to extraction and paper chromatography for the separation of T4 and T4-derived I-containing compounds. The activity of intramitochondrial α-glycerophosphate dehydrogenase (α-GPD) was measured in kidneys and liver. It was found that the total amount of I* was intensely decreased in all samples from cold-exposed animals. The proportion of this I* which was non-extractable was the same, in all tissues, for cold-exposed and control rats. The % of extractable tissue radioactivity in the form of T4 was decreased, and that found as T4-derived T3 was increased, in all samples from cold-exposed animals. The T3/T4 ratio was increased more than two-fold in all tissues studied. The concentration of T4 decreased significantly in all tissues, whereas the concentration of T3 in tissues of cold-exposed rats did not decrease. It actually increased in kidneys and lungs, and remained the same in liver and carcass. Despite the decrease in the concentration of T4 in the kidneys, α-GPD activity was increased in this tissue, where the concentration of T3 was increased. No change in the α-GPD activity was found for the liver, where the concentration of T3 was the same for cold-exposed and control rats. Thus, it appears likely that the conversion of T4 to T3 is increased by the exposure to cold of thyroidectomized rats on a constant dose of T4. α-GPD activity in a given tissue appears to be more closely related to the concentration of T3, than to that of T4.

Thermal balance and biogenic amine excretion in Gaspé fishermen exposed to cold

1964 ◽  
Vol 19 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Jacques Leblanc ◽  
M. Pouliot ◽  
S. Rheaume
Keyword(s):  
Body Temperature ◽  
Cold Stress ◽  
Skin Temperature ◽  
Biogenic Amine ◽  
Heat Production ◽  
Cold Exposure ◽  
Technical Assistance ◽  
Control Group ◽  
Catecholamine Excretion ◽  
Adrenergic Response

Previous studies have shown a decreased response in fishermen to cold applied locally. In the present study, the same subjects, when exposed naked for 1 hr at 60 F maintained a higher skin temperature than a control group. If these findings indicate a decreased vasoconstriction, all results obtained to date on these fishermen would indicate a decreased adrenergic response. Evidence of gross shivering was much more pronounced in the fishermen but this was not reflected by greater heat production. Both groups excreted more hydroxycortisone in the cold, and the excretion was higher in the control subjects. Cold exposure did not increase the catecholamine excretion in either group. Note: (With the Technical Assistance of P. Tousignant) acclimatization; body temperature; skin temperature; vasomotor adaptation; shivering; adrenergic response in cold habituation; hydroxycortisone excretion in cold stress Submitted on June 17, 1963

Effect of gonadotrophin-releasing hormone (GnRH) and GnRH agonists upon accumulation of progesterone, cAMP and prostaglandin in isolated preovulatory rat follicles

1982 ◽  
Vol 101 (4) ◽  
pp. 603-610 ◽  
Author(s):  
Torbjörn Hillensjö ◽  
William J. LeMaire ◽  
Martin R. Clark ◽  
Kurt Ahrén
Keyword(s):  
Phosphodiesterase Inhibitor ◽  
Fold Increase ◽  
Control Group ◽  
Prostaglandin E ◽  
Gnrh Agonists ◽  
Bicarbonate Buffer ◽  
Preovulatory Follicles ◽  
Camp Levels ◽  
Dose Dependent ◽  
Stimulation Of

Abstract. To study the acute and direct effects of GnRH agonists preovulatory follicles were isolated from PMSG-treated immature rats and incubated for 15–360 min in modified Kreb's bicarbonate buffer. The levels of cAMP, prostaglandin E, and progesterone were analysed in the tissue and/or incubation media. GnRH and two GnRH agonists produced a dose-dependent stimulation of progesterone production with maximal levels 5–6-fold higher than the control group. As compared to LH the magnitude of this effect was small and was detected only after 240–360 min of incubation. GnRH also stimulated prostaglandin E accumulation and this effect was as pronounced as for LH. There were no detectable changes in cAMP levels for any concentration of GnRH when the incubation time varied between 15 and 120 min whether or not a phosphodiesterase inhibitor was present, but after 240 min of incubation a 2-fold incease in cAMP was found. Consistent with previous results, LH caused a pronouced (40–50-fold) increase in follicular cAMP which was already detectable after 15 min of incubation. Indomethacin abolished the rise in prostaglandin E induced either by GnRH or LH but did not affect the response in terms of cAMP or progesterone, and did not affect the stimulation of meiotic maturation of the follicle-enclosed oocytes caused by the hormones. It is concluded that GnRH can exert acute and LH-like stimulatory effects on the preovulatory rat follicle but that the mechanism of GnRH action is different from that of LH.

Cold-Induced Skin Disorders

1996 ◽  
Vol 1 (2) ◽  
pp. 119-130
Author(s):  
H.L. Kim ◽  
Y. Bo-Abbas ◽  
Lyn C. Guenther
Keyword(s):  
Cold Exposure ◽  
Clinical Presentation ◽  
Heterogeneous Group ◽  
Current Understanding ◽  
Cold Climates ◽  
Skin Disorders ◽  
Cold Temperatures ◽  
Exposure To Cold

Background: Humans are commonly exposed to extremes in temperature. Fortunately, our skin behaves as an anatomic and physiologic barrier during these periods. Exposure to cold temperatures may result in a variety of symptoms and disorders. Objective: Our current understanding of the pathophysiology, clinical presentation, and therapies of cold-induced skin disorders are reviewed. Methods: Studies, reviews, and book chapters that contained information on cold-induced skin disorders were reviewed. Conclusion: Cold-induced skin disorders are a heterogeneous group of disorders that cause great morbidity, particularly in cold climates. These entities can be classified as physiologic or pathologic responses to freezing or nonfreezing cold exposure.

scholarly journals Changes in rat pituitary POMC mRNA after exposure to cold or a novel environment, detected by in situ hybridization.

1991 ◽  
Vol 39 (6) ◽  
pp. 843-852 ◽  
Author(s):  
P Wu ◽  
G V Childs
Keyword(s):  
Cold Exposure ◽  
Color Image ◽  
Fold Increase ◽  
Male Rats ◽  
Image Analysis System ◽  
Frozen Sections ◽  
Novel Environment ◽  
Pomc Mrna ◽  
Exposure To Cold

Plasma adrenocorticotropin (ACTH) levels increase after acute cold exposure. The purpose of this study was to determine if there were parallel changes in pituitary proopiomelanocortin (POMC) mRNA. Male rats were exposed to cold (3-5 degrees C) or a novel environment for 15 or 30 min. Others were unstressed. POMC mRNAs in frozen sections or dissociated cells were hybridized with a photobiotinylated oligonucleotide probe which was detected in situ by streptavidin-alkaline phosphatase. The percentage of area labeled for POMC mRNA was quantified by the Cue-3 color image analysis system. In frozen sections, 24-fold increases in the percentage of area labeled for POMC mRNA were evident in intermediate lobes (IL) 30 min after stress. No change was seen in anterior lobes (AL). If the ALs were dissociated, a 66-99% increase in percentage of labeled cells was detected 2-3 hr after the cold exposure. Fifteen min of cold stress (CS) also caused a 117% increase in the area of label for POMC mRNA per corticotrope. No change was seen after 30 min. Exposure to a novel environment caused a 73% increase in the percentage of area labeled for POMC mRNA per AL corticotrope and an 11-fold increase in the IL. These results indicate that both AL corticotropes and IL melanotropes are stimulated by acute exposure to cold and novel environments.

The effect of bundle of warmth care for patients with advanced colorectal cancer undergoing chemotherapy on reduction of oxaliplatin-related peripheral sensory neuropathy.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e15031-e15031
Author(s):  
Jin-Xiang Lin ◽  
Zhan-hong Chen ◽  
Xiang-Wei Chen ◽  
Zu-Yan Fan ◽  
Xiu-Yan Huang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Advanced Colorectal Cancer ◽  
Intervention Group ◽  
Sensory Neuropathy ◽  
Warm Water ◽  
Control Group ◽  
Peripheral Sensory Neuropathy ◽  
Exposure To Cold ◽  
Hands And Feet ◽  
Peripheral Sensory

e15031 Background: FOLFOX is the one of the most selected chemotherapy regimens for advanced colorectal carcinoma (aCC) patients, which includes oxaliplatin, 5-fu and leucovorin. However, oxaliplatin often causes chemotherapy-induced peripheral sensory neuropathy (CIPN) which is a common treatment-related adverse effect and affects long- term quality of life. The aim of the study is to observe the effect of warmth intervention on patients with advanced colorectal cancer undergoing chemotherapy. Methods: A total of 60 aCC patients were recruited. They were randomized into an intervention group (30 patients) and a control group (30 patients). The intervention group accepted the bundle of warmth care which included wearing cotton gloves and socks, washing hands and taking a bath with warm water, soaking hands and feet before sleep with warm water, reducing exposure to cold and avoiding cold food. The control group was treated with conventional health education which including how to reduce exposure to cold. CTCAE-4.0 was used to evaluate patient, s peripheral sensory neuropathy at baseline, 3 months, 6 months and 6 months after chemotherapy terminate. Results: At baseline, there was no peripheral sensory neuropathy in two groups. In 3 months, incidence of peripheral sensory neuropathy of intervention group and control group were 26.67%(Ⅰ:20.00%,Ⅱ:6.67%) VS 83.34% (Ⅰ:46.67%,Ⅱ:30.00%,Ⅲ:6.67%)(χ2= 22.289,p = 0.000). In 6 months, incidence of peripheral sensory neuropathy of two group were 36.67% (Ⅰ: 26.67%,Ⅱ: 10.00%) VS 93.34%(Ⅰ:46.67%,Ⅱ:30.00%,Ⅲ:16.67%) (χ2= 23.398,p = 0.000). 6 months after chemotherapy terminate, incidence of peripheral sensory nerve damage of two group were 13.33%(Ⅰ:10.00%,Ⅱ:3.33%) VS 33.34%(Ⅰ:6.67%,Ⅱ:10.00%,Ⅲ:6.67%) (χ2= 4.283,p = 0.233). Conclusions: Bundle of warmth care reduced oxaliplatin-related peripheral sensory neuropathy on patients with advanced colorectal cancer undergoing chemotherapy.

RNAi inhibition of mineralocorticoid receptors prevents the development of cold-induced hypertension

2008 ◽  
Vol 294 (4) ◽  
pp. H1880-H1887 ◽  
Author(s):  
Zhongjie Sun ◽  
Mahajoub Bello-Roufai ◽  
Xiuqing Wang
Keyword(s):  
Plasma Level ◽  
Critical Role ◽  
Control Level ◽  
Plasma Renin ◽  
Control Group ◽  
Renal Hypertrophy ◽  
Effective Prevention ◽  
Small Interference Rna ◽  
Exposure To Cold ◽  
Induced Hypertension

The objective was to determine whether the mineralocorticoid receptor (MR) plays a role in the initiation and development of cold-induced hypertension (CIH) by testing the hypothesis that the RNA interference (RNAi) inhibition of the MR attenuates CIH. The recombinant adeno-associated virus (AAV) carrying a short-hairpin small-interference RNA for MR (MRshRNA) or a scrambled sequence (ControlshRNA) was constructed. Six groups of albino mice were used (6 mice/group). Three groups were exposed to cold (6.7°C), whereas the remaining three groups were kept at room temperature (RT; warm) as controls. In each temperature condition, three groups received an intravenous injection of MRshRNA, ControlshRNA, or virus-free PBS, respectively, before exposure to cold. The viral complexes (0.35 × 1011 particles/mouse, 0.5 ml) or PBS (0.5 ml) was delivered into the circulation via the tail vein. The blood pressure (BP) of the mice treated with ControlshRNA or PBS increased significantly during exposure to cold, whereas the BP of the cold-exposed MRshRNA-treated mice did not increase and remained at the level of the control group kept at RT. Thus AAV delivery of MRshRNA prevented the initiation of CIH. MRshRNA significantly attenuated cardiac and renal hypertrophy. MRshRNA decreased the cold-induced increase in MR protein expression to the control level in the hypothalamus, kidneys, and heart, indicating an effective prevention of the cold-induced upregulation of MR. RNAi inhibition of MR resulted in significant decreases in the plasma level of norepinephrine, plasma renin activity, and plasma level of aldosterone in cold-exposed mice. MR played a critical role in the initiation and development of CIH. AAV delivery of MRshRNA may serve as a new approach for the prevention of cold-induced hypertension.

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