Heterogeneous response to PTH in aging rats: evidence for skeletal PTH resistance

1991 ◽  
Vol 260 (6) ◽  
pp. E933-E937 ◽  
Author(s):  
J. Fox ◽  
M. B. Mathew
Keyword(s):  
Age Groups ◽  
Metabolic Clearance ◽  
Aged Rats ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Dihydroxyvitamin D3 ◽  
Sprague Dawley Rats ◽  
Steady State Levels ◽  
Pth Resistance ◽  
Immunoreactive Parathyroid Hormone

Plasma immunoreactive parathyroid hormone (irPTH) levels increase and renal responsiveness to pharmacological doses of PTH decreases with advancing age. This study tested whether 1) decreased irPTH clearance contributes to the elevated NH2-terminal irPTH levels seen in aged rats and 2) aged rats respond to physiological levels of rat PTH. Conscious adult (7-mo-old) and aged (25-mo-old) male Sprague-Dawley rats were infused for 2 h with rat PTH-(1-34) to achieve steady-state levels in plasma (110-120 pg/ml). Basal irPTH levels were 77% higher (P less than 0.01), and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] levels were 46% lower (P less than 0.05) in the aged rats. Renal function was not significantly different in these two groups. The metabolic clearance rate of irPTH was rapid and not different in adult and aged rats (99 +/- 8 vs. 111 +/- 7 ml.min-1.kg-1, respectively). After the PTH infusion, plasma ionized and total calcium and 1,25(OH)2D3 levels increased significantly in adult rats, whereas no changes were observed in aged rats. In contrast, a similar significant hypophosphatemic response (23-25% decrease) was seen in both age groups, but the hypophosphatemia was maintained for longer in aged rats. Thus the elevated plasma irPTH levels in aged rats are caused solely by increased secretion. Finally, there is a heterogeneity in the responses to PTH infusion in aged rats, suggesting that the aged rat skeleton, like the kidney, is PTH resistant.

Regulation of parathyroid hormone secretion by plasma calcium in aging rats

1991 ◽  
Vol 260 (2) ◽  
pp. E220-E225 ◽  
Author(s):  
J. Fox
Keyword(s):  
Parathyroid Hormone ◽  
Hormone Secretion ◽  
Fold Increase ◽  
Male Rats ◽  
Aged Rats ◽  
Adult Rats ◽  
Dihydroxyvitamin D3 ◽  
Set Point ◽  
Skeletal Resistance ◽  
Immunoreactive Parathyroid Hormone

Plasma immunoreactive parathyroid hormone (irPTH) levels increase with aging. This study determined 1) whether NH2-terminal irPTH secretory responses to induced hypocalcemia differ between adult (6-mo-old) and aged (24- to 26-mo-old) male rats and 2) whether a higher set point for irPTH release by Ca is responsible for the elevated irPTH levels with aging. Basal irPTH levels were 68% higher and 1,25-dihydroxyvitamin D3 levels were 44% lower in aged rats. An acutely induced, constant hypocalcemic stimulus [0.32 mM decrement in ionized Ca (Ca2+) for 2 h] was developed in catheterized conscious adult and aged rats by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) infusion using the Ca clamp technique. The initial irPTH secretory response to acute hypocalcemia (5-10 min) was reduced in aged rats (1.9- vs. 3.1-fold increase), suggesting reduced hormone stores. However, higher sustained irPTH levels (30 min to 2 h) were maintained in aged rats, indicating increased irPTH synthesis and release. The EGTA infusion rate necessary to maintain constant hypocalcemia was less in aged rats, suggesting skeletal resistance to PTH. Slow EGTA and Ca infusions were used to determine irPTH secretion at plasma Ca2+ levels from 0.7 to 1.5 mM. In aged rats, irPTH levels were higher at all Ca2+ concentrations, but the set point for irPTH release by Ca2+ was the same as in adult rats. Thus the elevated irPTH secretion in aged rats is not caused by a change in the set point for irPTH release but does result in decreased irPTH stores.

Kinetic impairment of nitrogen and muscle glutamine metabolisms in old glucocorticoid-treated rats

1999 ◽  
Vol 276 (3) ◽  
pp. E558-E564 ◽  
Author(s):  
Regine Minet-Quinard ◽  
Christophe Moinard ◽  
Françoise Villie ◽  
Stephane Walrand ◽  
Marie-Paule Vasson ◽  
...  
Keyword(s):  
Control Group ◽  
Synthetase Activity ◽  
Aged Rats ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Glucocorticoid Treatment ◽  
Sprague Dawley Rats ◽  
End Of Treatment ◽  
Catabolic State ◽  
Old Rats

Aged rats are more sensitive to injury, possibly through an impairment of nitrogen and glutamine (Gln) metabolisms mediated by glucocorticoids. We studied the metabolic kinetic response of adult and old rats during glucocorticoid treatment. The male Sprague-Dawley rats were 24 or 3 mo old. Both adult and old rats were divided into 7 groups. Groups labeled G3, G5, and G7 received, by intraperitoneal injection, 1.50 mg/kg of dexamethasone (Dex) for 3, 5, and 7 days, respectively. Groups labeled G3PF, G5PF, and G7PF were pair fed to the G3, G5, or G7 groups and were injected with an isovolumic solution of NaCl. One control group comprised healthy rats fed ad libitum. The response to aggression induced specifically by Dex (i.e., allowing for variations in pair-fed controls) appeared later in the aged rats (decrease in nitrogen balance from day 1 in adults but only from day 4 in old rats). The adult rats rapidly adapted to Dex treatment, whereas the catabolic state worsened until the end of treatment in the old rats. Gln homeostasis was not maintained in the aged rats; despite an early increase in muscular Gln synthetase activity, the Gln pool was depleted. These results suggest a kinetic impairment of both nitrogen and muscle Gln metabolisms in response to Dex with aging.

scholarly journals Age-related decline in the taurine content of the skin in rodents

Amino Acids ◽  
2021 ◽  
Author(s):  
Tomohisa Yoshimura ◽  
Yuki Inokuchi ◽  
Chikako Mutou ◽  
Takanobu Sakurai ◽  
Tohru Nagahama ◽  
...  
Keyword(s):  
High Performance ◽  
Age Groups ◽  
Immunohistochemical Analysis ◽  
Sprague Dawley ◽  
Taurine Supplementation ◽  
Hairless Mice ◽  
Age Related ◽  
Sprague Dawley Rats ◽  
High Concentrations ◽  
Effects Of Aging

AbstractTaurine, a sulfur-containing amino acid, occurs at high concentrations in the skin, and plays a role in maintaining the homeostasis of the skin. We investigated the effects of aging on the content and localization of taurine in the skin of mice and rats. Taurine was extracted from the skin samples of hairless mice and Sprague Dawley rats, and the taurine content of the skin was determined by high-performance liquid chromatography (HPLC). The results of the investigation revealed that the taurine content in both the dermis and epidermis of hairless mice declined significantly with age. Similar age-related decline in the skin taurine content was also observed in rats. In contrast, the taurine content in the sole remained unchanged with age. An immunohistochemical analysis also revealed a decreased skin taurine content in aged animals compared with younger animals, although no significant differences in the localization of taurine were observed between the two age groups. Supplementation of the drinking water of aged mice with 3% (w/v) taurine for 4 weeks increased the taurine content of the epidermis, but not the dermis. The present study showed for the first time that the taurine content of the skin decreased with age in mice and rats, which may be related to the impairment of the skin homeostasis observed with aging. The decreased taurine content of the epidermis in aged animals was able to be rescued by taurine supplementation.

scholarly journals Effects of adolescent caffeine consumption on cocaine self-administration and reinstatement of cocaine seeking

2018 ◽  
Vol 33 (1) ◽  
pp. 132-144
Author(s):  
Tracey A Larson ◽  
Casey E O’Neill ◽  
Michaela P Palumbo ◽  
Ryan K Bachtell
Keyword(s):  
Dose Response ◽  
Extinction Training ◽  
Schedules Of Reinforcement ◽  
Sprague Dawley ◽  
Self Administration ◽  
Caffeine Consumption ◽  
Adult Rats ◽  
Sprague Dawley Rats ◽  
Cocaine Seeking ◽  
Administration Procedure

Background: Caffeine consumption by children and adolescents has risen dramatically in recent years, yet the lasting effects of caffeine consumption during adolescence remain poorly understood. Aim: These experiments explore the effects of adolescent caffeine consumption on cocaine self-administration and seeking using a rodent model. Methods: Sprague-Dawley rats consumed caffeine for 28 days during the adolescent period. Following the caffeine consumption period, the caffeine solution was replaced with water for the remainder of the experiment. Age-matched control rats received water for the duration of the study. Behavioral testing in a cocaine self-administration procedure occurred during adulthood (postnatal days 62–82) to evaluate how adolescent caffeine exposure influenced the reinforcing properties of cocaine. Cocaine seeking was also tested during extinction training and reinstatement tests following cocaine self-administration. Results: Adolescent caffeine consumption increased the acquisition of cocaine self-administration and increased performance on different schedules of reinforcement. Consumption of caffeine in adult rats did not produce similar enhancements in cocaine self-administration. Adolescent caffeine consumption also produced an upward shift in the U-shaped dose response curve on cocaine self-administration maintained on a within-session dose-response procedure. Adolescent caffeine consumption had no effect on cocaine seeking during extinction training or reinstatement of cocaine seeking by cues or cocaine. Conclusions: These findings suggest that caffeine consumption during adolescence may enhance the reinforcing properties of cocaine, leading to enhanced acquisition that may contribute to increased addiction vulnerability.

scholarly journals Protective effects of dietary fibre against manganese-induced neurobehavioral aberrations in rats

2012 ◽  
Vol 63 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Xiu-Quan Shi ◽  
Wei Yan ◽  
Ke-Yue Wang ◽  
Qi-Yuan Fan ◽  
Yan Zou
Keyword(s):  
Cerebral Cortex ◽  
Animal Feed ◽  
Oral Exposure ◽  
Protective Effects ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Neurobehavioral Performance ◽  
Sprague Dawley Rats ◽  
Applied Dose ◽  
Mn Concentrations

We tested the hypothesis that dietary fi bre (DF) has protective effects against manganese (Mn)-induced neurotoxicity. Forty-eight one-month old Sprague-Dawley rats were randomly divided into six groups: control, 16 % DF, Mn (50 mg kg-1 body weight), Mn+ 4 % DF, Mn+ 8 % DF, and Mn+ 16 % DF. After oral administration of Mn (as MnCl2) by intragastric tube during one month, we determined Mn concentrations in the blood, liver, cerebral cortex, and stool and tested neurobehavioral functions. Administration of Mn was associated with increased Mn concentration in the blood, liver, and cerebral cortex and increased Mn excretion in the stool. Aberrations in neurobehavioral performance included increases in escape latency and number of errors and decrease in step-down latency. Irrespective of the applied dose, the addition of DF in forage decreased tissue Mn concentrations and increased Mn excretion rate in the stool by 20 % to 35 %. All neurobehavioral aberrations were also improved. Our fi ndings show that oral exposure to Mn may cause neurobehavioral abnormalities in adult rats that could be effi ciently alleviated by concomitant supplementation of DF in animal feed.

Distribution and metabolism of corticotropin-releasing factor in the rat

1986 ◽  
Vol 64 (6) ◽  
pp. 683-688 ◽  
Author(s):  
Bernard Candas ◽  
Josée Lalonde ◽  
Maurice Normand
Keyword(s):  
Time Course ◽  
Corticotropin Releasing Factor ◽  
Metabolic Clearance ◽  
Sprague Dawley ◽  
Rapid Injection ◽  
Sprague Dawley Rats ◽  
Significant Difference ◽  
The Mean ◽  
The Moment ◽  
The One

To develop a mathematical model of the distribution and metabolism of rat corticotropin-releasing factor (rCRF), the time course of 125I-labelled rCRF in plasma was measured in male Sprague–Dawley rats (i) following a rapid injection of 24 ng rCRF/100 g body weight (BW), or (ii) following a rapid injection of 424 ng rCRF/100 g BW, or (iii) during an infusion at a rate ranging from 0.28 to0.73 ng rCRF∙min−1∙100 g BW−1. The comparison of the one-, two-, and three-compartment models shows that the two-pool structure fits better to the dynamics of CRF in plasma as measured in each rat. Following a rapid injection the decay curve occurs in a biphasic manner; the early phase of disappearance is 25 times faster than the late one. There is no significant difference between the estimates of the metabolic clearance rate following both amplitudes of injection (0.40 ± 0.06 and 0.48 ± 0.05 mL∙min−1∙100 g BW−1). The volume of the first pool, 16.8 ± 1.1 mL/100 g BW, is four times larger than the plasma volume. It would thus appear that CRF is rapidly distributed from plasma into several tissues which are represented in the first pool of the model. The mean residence time of every CRF molecule in the second compartment, from the moment of secretion to its elimination, is from three to four times longer than in the first one. It stays, on average, between 140 min and 3 h in the system before an irreversible exit. At steady state, the disposal rate represents only 3% of the CRF mass of the first compartment every minute. These results could explain the prolonged effects of CRF on pituitary-adrenocortical secretion.

Long Term Cerebrovascular Dysfunction in the Offspring from Maternal Electronic Cigarette Use during Pregnancy

2021 ◽  
Author(s):  
E.N. Burrage ◽  
Eiman Aboaziza ◽  
Lance Hare ◽  
Sarah Reppert ◽  
Joshua Moore ◽  
...  
Keyword(s):  
Electronic Cigarettes ◽  
Vascular Dysfunction ◽  
Age Groups ◽  
Adult Life ◽  
Ambient Air ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Vasoconstrictor Response ◽  
Cerebrovascular Dysfunction ◽  
Old Adult

Electronic cigarettes (E-cigs) have been promoted as harm-free or less-risky than smoking, even for women during pregnancy. These claims are made largely on E-cig aerosol having fewer number of toxic chemicals compared to cigarette smoke. Given that even low levels of smoking are found to produce adverse birth outcomes, we sought to test the hypothesis that vaping during pregnancy (with or without nicotine) would not be harm-free, and would result in vascular dysfunction that would be evident in offspring during adolescent and/or adult life. Pregnant female Sprague Dawley rats were exposed to E-cig aerosol (1-hour/day, 5 days/week, starting on gestational day 2 until pups were weaned) using e-liquid with 0 mg/ml (E-cig0) or 18 mg/ml nicotine (E-cig18) and compared to ambient air exposed controls. Body mass at birth and at weaning were not different between groups. Assessment of middle cerebral artery (MCA) reactivity revealed a 51-56% reduction in endothelial-dependent dilation response to acetylcholine (ACh) for both E-cig0 and E-cig18 in 1-month, 3-month (adolescent), and 7-month old (adult) offspring (p<0.05 compared to air, all time points). MCA response to sodium nitroprusside (SNP) and myogenic tone were not different across groups suggesting that endothelial-independent responses were not altered. The MCA vasoconstrictor response (5-hydroxytryptamine, 5-HT) was also not different across treatment and age groups. These data demonstrate that maternal vaping during pregnancy is not harm-free and confers significant cerebrovascular health risk/dysfunction to offspring that persists into adult life.

scholarly journals Synergistic toxicity in an in vivo model of neurodegeneration through the co-expression of human TDP-43M337V and tauT175D protein

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Alexander J. Moszczynski ◽  
Madeline Harvey ◽  
Niveen Fulcher ◽  
Cleusa de Oliveira ◽  
Patrick McCunn ◽  
...  
Keyword(s):  
Tau Protein ◽  
Sensorimotor Gating ◽  
In Vivo Model ◽  
Motor Deficits ◽  
Sprague Dawley ◽  
Tau Pathology ◽  
Adult Rats ◽  
Sprague Dawley Rats ◽  
Somatic Gene Transfer

Abstract Although it has been suggested that the co-expression of multiple pathological proteins associated with neurodegeneration may act synergistically to induce more widespread neuropathology, experimental evidence of this is sparse. We have previously shown that the expression of Thr175Asp-tau (tauT175D) using somatic gene transfer with a stereotaxically-injected recombinant adeno-associated virus (rAAV9) vector induces tau pathology in rat hippocampus. In this study, we have examined whether the co-expression of human tauT175D with mutant human TDP-43 (TDP-43M337V) will act synergistically. Transgenic female Sprague-Dawley rats that inducibly express mutant human TDP-43M337V using the choline acetyltransferase (ChAT) tetracycline response element (TRE) driver with activity modulating tetracycline-controlled transactivator (tTA) were utilized in these studies. Adult rats were injected with GFP-tagged tau protein constructs in a rAAV9 vector through bilateral stereotaxic injection into the hippocampus. Injected tau constructs were: wild-type GFP-tagged 2N4R human tau (tauWT; n = 8), GFP-tagged tauT175D 2N4R human tau (tauT175D, pseudophosphorylated, toxic variant, n = 8), and GFP (control, n = 8). Six months post-injection, mutant TDP-43M337V expression was induced for 30 days. Behaviour testing identified motor deficits within 3 weeks after TDP-43 expression irrespective of tau expression, though social behaviour and sensorimotor gating remained unchanged. Increased tau pathology was observed in the hippocampus of both tauWT and tauT175D expressing rats and tauT175D pathology was increased in the presence of cholinergic neuronal expression of human TDP-43M337V. These data indicate that co-expression of pathological TDP-43 and tau protein exacerbate the pathology associated with either individual protein.

scholarly journals Cerebral cortex does not modulate “regulated” decrease in core temperature during hypoxemia in rats

1998 ◽  
Vol 274 (4) ◽  
pp. R1158-R1161
Author(s):  
Evvi-Lynn M. Rollins ◽  
James E. Fewell
Keyword(s):  
Cerebral Cortex ◽  
Core Temperature ◽  
Cortical Spreading Depression ◽  
Spreading Depression ◽  
Temperature Response ◽  
Sprague Dawley ◽  
Adult Rats ◽  
The Core ◽  
Sprague Dawley Rats ◽  
Before And After

In newborns and adults of a number of species including humans, exposure to acute hypoxemia produces a “regulated” decease in core temperature, the mechanism of which is unknown. Considering that various cortical areas participate in autonomic regulation including thermoregulation, the present experiments were carried out to test the hypothesis that the cerebral cortex plays a role in modulating the regulated decrease in core temperature during acute hypoxemia. This hypothesis was tested by determining the core temperature response to acute hypoxemia in chronically instrumented adult Sprague-Dawley rats before and after cortical spreading depression (i.e., functional decortication) was produced by the local application of potassium chloride to the dura overlying the cerebral hemispheres. There was no effect of cortical spreading depression on baseline core temperature. Core temperature decreased during acute hypoxemia in a similar fashion when the cerebral cortex was intact as well as during functional decortication. Thus our data do not support the hypothesis that the cerebral cortex modulates the regulated decrease in core temperature that occurs in adult rats during acute hypoxemia.

ULTRAMORPHOMETRIC STUDIES OF THE ADRENAL CORTEX OF ADULT RATS AFTER NEONATAL ADMINISTRATION OF SEX STEROIDS

1976 ◽  
Vol 81 (2) ◽  
pp. 537-547 ◽  
Author(s):  
E. Mäusle ◽  
G. Fickinger
Keyword(s):  
Sex Steroids ◽  
Smooth Endoplasmic Reticulum ◽  
Zona Fasciculata ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Sprague Dawley Rats ◽  
Neonatal Administration ◽  
The Individual ◽  
Increased Activity ◽  
Functional Reaction

ABSTRACT The outer zona fasciculata of 28 Sprague-Dawley rats, 8 weeks old, was studied by means of ultramorphometry. Four males and 4 females each received 1250 μg of testosterone proprionate (TP) or 300 μg oestradiol benzoate (OeB) on the second day of life. Four males and 4 females in oestrus or dioestrus served as controls. The controls showed both sex and cyclic differences: in comparison to the males, females displayed a finely dispersed lipoid pattern; enlargement of the nucleus and an increase in the amount of smooth endoplasmic reticulum (SER) indicated an increased stimulation of the cortex during oestrus. Neonatal administration of TP in females causes a distinct enlargement of cells with an increase in the volumes of nucleus, mitochondria, liposomes, SER and liposomes. The mitochondria and liposomes show a small-dispersed pattern of distribution. All these function-specific morphometric parameters point to an increased activity of the individual cell. The changes are less pronounced after OeB than after TP. In the male, neonatal administration of sex steroids results in an alteration of the sizes of the mitochondria and liposomes. The liposomes are distributed finely dispersed. At the same time there is an increase in the lipoid content. According to these parameters, fasciculata cells fulfil the morphological conditions that are a prerequisite for an elevated functional reaction. This change is more marked following OeB than TP. Sex dimorphism is preserved following neonatal application of sex steroids since the alterations are much more pronounced in females than in males.

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