Corticotropin responses to hypoglycemia and hypotension during ovine pregnancy

1994 ◽  
Vol 266 (1) ◽  
pp. R180-R187
Author(s):  
M. Keller-Wood
Keyword(s):  
Adrenocorticotropic Hormone ◽  
Regular Insulin ◽  
Plasma Acth ◽  
Specific Effects ◽  
Arterial Blood ◽  
Multiple Stimulus ◽  
The Mean ◽  
Pregnant State ◽  
The Right ◽  
Pituitary Adrenal Axis

The adrenocorticotropic hormone (ACTH) responses to hypoglycemia and to hypotension were compared in pregnant and nonpregnant ewes. In the first study pregnant and nonpregnant ewes were each subjected to hypoglycemia induced by injection of 0.05, 0.10, or 0.25 U regular insulin/kg body wt or to saline infused as a control. In the second study pregnant and nonpregnant ewes were subjected to hypotension induced by the infusion of 2.5, 5.0, or 10.0 micrograms nitroprusside.kg-1.min-1 or to dextrose infused as a control. ACTH responses to hypoglycemia were significantly increased in the pregnant ewes, and the relation between plasma glucose and plasma ACTH was shifted to the right, indicating greater ACTH responses for a given level of hypoglycemia in the pregnant state. The mean ACTH response to infusion of nitroprusside was reduced during pregnancy, despite significantly lower mean arterial blood pressure in the pregnant ewes. When the relation between mean arterial pressure and ACTH was compared in the two groups of ewes, the relation was significantly shifted to the left in the pregnant ewes, indicating lower ACTH responses to a given level of pressure during pregnancy. The results suggest that pregnancy does not uniformly alter ACTH responses to stimuli, suggesting multiple, stimulus-specific effects of pregnancy on the hypothalamo-pituitary-adrenal axis.

scholarly journals Effect of delayed plasma centrifugation on equine adrenocorticotropic hormone concentration

2019 ◽  
Vol 31 (4) ◽  
pp. 585-587 ◽  
Author(s):  
Kayla N. Shepard ◽  
John C. Haffner ◽  
Dwana L. Neal ◽  
Steven T. Grubbs ◽  
Greg L. Pearce
Keyword(s):  
Whole Blood ◽  
Adrenocorticotropic Hormone ◽  
Animal Health ◽  
Pars Intermedia ◽  
Plasma Acth ◽  
Cornell University ◽  
Diagnostic Center ◽  
Acth Concentration ◽  
Baseline Values ◽  
The Mean

Plasma adrenocorticotropic hormone (ACTH) concentration is used in the diagnosis of pituitary pars intermedia dysfunction (PPID) in horses. We enrolled 10 horses, 5 PPID-positive and 5 PPID-negative, in our study, September 20–22, 2016. On day 0, 5 mL of whole blood was collected into each of 6 EDTA tubes and immediately placed in a refrigerator at 7°C. One tube was centrifuged within 15 min of collection, followed by centrifugation of one tube from each horse at 4, 8, 12, 24, and 36 h following collection. At each time, centrifuged plasma was pipetted into 1.5-mL polypropylene tubes and stored at −80°C. None of the plasma samples were turbid, hemolyzed, or icteric. Plasma was shipped frozen with cold packs overnight to the Animal Health Diagnostic Center of Cornell University (Ithaca, NY) for analysis. The percent change from baseline (PCFB) was reported to standardize the data given that baseline values differed. The mean PCFB was 2.8 (95% confidence interval: –2.9%, 7.0%). Neither refrigeration of whole blood for up to 36 h prior to centrifugation nor freezing affected plasma ACTH concentrations significantly.

Vasopressin response to hyperosmolality and hypotension during ovine pregnancy

1994 ◽  
Vol 266 (1) ◽  
pp. R188-R193 ◽  
Author(s):  
M. Keller-Wood
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Arginine Vasopressin ◽  
Sodium Concentration ◽  
Plasma Sodium ◽  
Arterial Blood ◽  
Plasma Sodium Concentration ◽  
Blood Pressures ◽  
The Mean ◽  
Pregnant State

The arginine vasopressin (AVP) responses to hyperosmolality and to hypotension were compared in pregnant and nonpregnant ewes. When the responses to infusion of normal or hypertonic saline were compared, plasma AVP and Na+ concentrations were lower in pregnant ewes than nonpregnant ewes, but the relation between plasma AVP and Na+ concentrations was not altered in the pregnant state. In a second study the AVP response to hypotension, induced by the infusion of 2.5, 5.0, or 10.0 micrograms nitroprusside.kg-1.min-1, was compared in pregnant and nonpregnant ewes. Despite significantly lower mean arterial blood pressures in the pregnant ewes, the mean plasma AVP concentration after infusion of nitroprusside was not increased during pregnancy. Therefore, the relation between mean arterial pressure and AVP was significantly shifted to the left in the pregnant ewes, indicating lower AVP concentrations for a given level of arterial pressure during pregnancy. The results suggest that pregnancy alters the regulation of AVP by arterial pressure but does not affect the regulation of AVP by plasma sodium concentration in the ewe.

Effect of systemic hypotension on cerebral energy metabolism during chronic cerebral vasospasm in primates

1993 ◽  
Vol 78 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Yuji Handa ◽  
Tetsuya Kubota ◽  
Akira Tsuchida ◽  
Masanori Kaneko ◽  
Hakan Caner ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Cerebral Vasospasm ◽  
Mr Spectroscopy ◽  
High Energy ◽  
Cerebral Energy Metabolism ◽  
Systemic Hypotension ◽  
Arterial Blood ◽  
The Mean ◽  
The Right ◽  
Chronic Cerebral Vasospasm

✓ The influence of systemic hypotension on cerebral blood flow (CBF) and energy metabolism during chronic cerebral vasospasm after subarachnoid hemorrhage was studied in 15 monkeys. Changes in the phosphorus spectrum, as demonstrated by in vivo phosphorus-31 (31P) magnetic resonance (MR) spectroscopy, or in regional CBF were measured in the parietal cortex during graded hypotension. Sequential changes in the phosphorus spectrum were observed during moderate hypotension in the animals 7 days after the introduction of an autologous blood clot around the right middle cerebral artery (MCA). Angiograms revealed a reduction in vessel caliber by approximately 50% in the right MCA. The mean CBF in the spasm side decreased in parallel with a decrease in the mean arterial blood pressure (MABP) from 120 to 40 mm Hg, indicating the abolition of autoregulation. There were no significant differences in the mean percentage totals of inorganic phosphate (Pi), phosphocreatine (PCr), adenosine triphosphate (ATP), and pH between the hemispheres at baseline MABP before hypotension. The values of PCr, ATP, and pH decreased significantly (p < 0.05) and Pi increased significantly (p < 0.05) at an MABP of less than 60 mm Hg in the involved hemisphere. The ratio of PCr:Pi decreased in parallel with a decrease in MABP. The ATP showed a stepwise decrease during moderate hypotension (MABP 60 mm Hg) and was reduced significantly 20 minutes after the beginning of hypotension (p < 0.05). The results indicate that, during chronic vasospasm, changes in cerebral energy metabolism are coupled with changes in CBF in the state of impaired autoregulation. There exists a critical level for ischemia below which high-energy phosphorus metabolites become markedly depleted. It is suggested that 31P MR spectroscopy may be useful to evaluate the ischemic vulnerability of brain tissue in order to prevent delayed neurological deficit during cerebral vasospasm.

scholarly journals Captopril Partially Decreases the Effect of H2S on Rat Blood Pressure and Inhibits H2S-Induced Nitric Oxide Release From S-Nitrosoglutathione

2015 ◽  
pp. 479-486 ◽  
Author(s):  
M. DROBNÁ ◽  
A. MISAK ◽  
T. HOLLAND ◽  
F. KRISTEK ◽  
M. GRMAN ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Biological Activities ◽  
Renin Angiotensin System ◽  
Bolus Administration ◽  
Angiotensin System ◽  
Nitric Oxide Release ◽  
Arterial Blood ◽  
Biphasic Effect ◽  
The Mean ◽  
The Right

We studied the effects of the H2S donor Na2S on the mean arterial blood pressure (MAP) and heart and breathing rates of anesthetized Wistar rats in the presence and absence of captopril. Bolus administration of Na2S (1-4 µmol/kg) into the right jugular vein transiently decreased heart and increased breathing rates; at 8-30 µmol/kg, Na2S had a biphasic effect, transiently decreasing and increasing MAP, while transiently decreasing heart rate and increasing and decreasing breathing rate. These results may indicate independent mechanisms by which H2S influences MAP and heart and breathing rates. The effect of Na2S in decreasing MAP was less pronounced in the presence of captopril (2 µmol/l), which may indicate that the renin-angiotensin system is partially involved in the Na2S effect. Captopril decreased H2S-induced NO release from S-nitrosoglutathione, which may be related to some biological activities of H2S. These results contribute to the understanding of the effects of H2S on the cardiovascular system.

Control of canine ACTH by corticosteroids: an integral feedback effect of steroids

1989 ◽  
Vol 257 (2) ◽  
pp. R427-R430 ◽  
Author(s):  
M. Keller-Wood
Keyword(s):  
Time Domain ◽  
Adrenocorticotropic Hormone ◽  
Corticosteroid Treatment ◽  
Steroid Treatment ◽  
Feedback Signal ◽  
Plasma Acth ◽  
Corticosteroid Dose ◽  
Treatment Changes ◽  
The Mean ◽  
Total Interval

These experiments were designed to test whether the pattern of change in plasma corticosteroid or the total corticosteroid dose is important in determining the degree of inhibition of adrenocorticotropic hormone (ACTH) responses to stress by corticosteroid intermediate-delayed feedback. Five conscious dogs were studied. The ACTH response to induced hypoglycemia was measured after no prior corticosteroid feedback signal or after a corticosteroid feedback signal produced by infusion, two bolus injections, or three bolus injections of cortisol and corticosterone. The total corticosteroid dose (45 micrograms/kg) and the total interval of steroid treatment (60-30 min before hypoglycemia) were the same in all three cases of corticosteroid treatment. Changes in plasma glucose concentration during induced hypoglycemia were not altered by corticosteroid treatment. The plasma ACTH response to hypoglycemia was inhibited by all three patterns of treatment with corticosteroids. The inhibition of ACTH response was not significantly altered among the patterns of treatment with corticosteroids. The data suggest that the integrated (total) or the mean change in plasma corticosteroid concentration over time determines the degree of inhibition of stimulated ACTH in this time domain.

Relationship of blood flow and myocardial Rb86 clearance in right and left ventricles

1963 ◽  
Vol 205 (2) ◽  
pp. 382-384 ◽  
Author(s):  
William D. Love ◽  
Lawrence P. O'Meallie
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Venous Blood ◽  
Percentage Error ◽  
Fick Principle ◽  
Mean Error ◽  
Arterial Blood ◽  
The Mean ◽  
The Right ◽  
Relationship Of

The rate of myocardial clearance of Rb86 from arterial blood and the rate of coronary blood flow were studied simultaneously during a 10-min period of isotope infusion in dogs. In order to measure blood flow to the right and left ventricles separately using the Fick principle, venous blood was obtained from an anterior cardiac vein and from the coronary sinus. The relationship of myocardial blood flow and Rb86 clearance was not detectably different in the right and left ventricles. The percentage error in predicting flow from clearance rose as the values increased. At rates of flow below 6 ml/g 10 min the mean error was 4.7%. From 6 to 12 ml/g 10 min the mean error was 10.0% in controls and 14.4% in a group with pulmonary embolism or obstruction of the pulmonary artery. Since the clearance technique does not require catheterization of a cardiac vein, this method can be used to study coronary blood flow under conditions approximating the undisturbed state.

2 Hz Electro-Acupuncture at Yinlingquan (SP9) and Ququan (LR8) Acupoints Induces Changes in Blood Flow in the Liver and Spleen

2012 ◽  
Vol 40 (01) ◽  
pp. 75-84 ◽  
Author(s):  
Wen-Cheng Chou ◽  
Hsu-Jan Liu ◽  
Yi-Wen Lin ◽  
Chin-Yi Cheng ◽  
Tsai-Chung Li ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
The Body ◽  
Arterial Blood ◽  
Flow Perfusion ◽  
Significant Difference ◽  
Specific Organ ◽  
The Mean ◽  
The Right ◽  
Measurement Period

According to the principles of traditional Chinese medicine, channels and collaterals within the body provide pathways through which qi and blood travel, and each channel or collateral is linked with a specific organ. The Yinlingquan (spleen 9, SP9) and Ququan (liver 8, LR8) acupoints represent the sea points of the spleen and liver meridians, respectively, from which qi and blood flow into their specific visceral organs. The purpose of this study was to investigate the changes in blood flow/perfusion in the liver and spleen resulting from the application of 2 Hz electro-acupuncture (EA) to the Yinlingquan (SP9) or Ququan (LR8) acupoints. A total of 18 Spragrue-Dawley rats were randomly divided into three groups of six rats each as follows: sham group receiving sham EA; Yinlingquan (SP9) group receiving 2 Hz EA, applied at bilateral Yinlingquan (SP9) acupoints; and Ququan (LR8) groups receiving 2 Hz EA, applied at bilateral Ququan (LR8) acupoints. The mean blood flow/perfusion of the spleen and liver was recorded using a laser Doppler blood flow monitor prior to EA (representing the baseline), during EA, and post-EA. Each measurement period lasted ten minutes. Nitric oxide levels were also measured from the right femoral arterial blood, following the conclusion of each series of blood flow/perfusion recordings. The results indicate that the sham EA did not increase the mean blood flow/perfusion in the liver or spleen; 2 Hz EA at bilateral Yinlingquan (SP9) acupoints increased the mean blood flow/perfusion in the spleen, but not in the liver. In contrast, 2 Hz EA at bilateral Ququan (LR8) acupoints increased the mean blood flow/perfusion in the liver, but not in the spleen. Nitric oxide levels showed no significant difference between any of the groups at any stage of the measurements. According to the results, we conclude that EA at the Yinlingquan (SP9) and Ququan (LR8) acupoints can increase the blood flow in the spleen and liver, respectively.

Effects of Isoproterenol, Diazoxide, Ethacrynic Acid, and Furosemide on Skeletal Muscle Vascular Resistance

1973 ◽  
Vol 51 (3) ◽  
pp. 183-189 ◽  
Author(s):  
P. Larochelle ◽  
E. Mikulic ◽  
R. I. Ogilvie
Keyword(s):  
Skeletal Muscle ◽  
Ethacrynic Acid ◽  
Perfusion Pressure ◽  
Gracilis Muscle ◽  
Maximal Effect ◽  
Vasodilator Response ◽  
Arterial Blood ◽  
Constant Rate ◽  
The Mean ◽  
The Right

The vasodilator properties of isoproterenol, diazoxide, ethacrynic acid, and furosemide were compared in the isolated canine gracilis muscle perfused with arterial blood at a constant rate. Isoproterenol was the most potent agent with a steep vasodilator response to 10−8–10−6 M infusions and a maximal decrease in perfusion pressure of 45.5 ± 2.9% at the 10−6 M concentration. The dose – vasodilator responses for diazoxide and ethacrynic acid were parallel to that for isoproterenol but shifted three log doses to the right. The dose–response for furosemide was almost flat with a maximal vasodilator response of 15.5 ± 2.3% at the 10−2 M concentration. The maximal effect of isoproterenol was noted within 5 min of starting the infusion whereas for diazoxide and furosemide it was noted after 10 min and for ethacrynic acid after 20 min. The mean ratio of venous to arterial resistance was unaltered during isoproterenol infusions, decreased with 10−3 M diazoxide, and increased with 10−3 M ethacrynic acid; however, none of these changes were statistically significant. Capillary hydrostatic pressure was significantly decreased only with higher concentrations of isoproterenol and diazoxide, an average of 6 mm Hg with 10−7 M isoproterenol, 8 mm Hg with 10−6 M isoproterenol, and 9 mm Hg with 10−3 M diazoxide. No significant changes in capillary pressure were noted during infusion of ethacrynic acid or furosemide. The results clearly differentiate these agents on the basis of potency, onset, and characteristics of vasodilator effect on sequential segments of a skeletal muscle vascular bed.

scholarly journals The Value of Adrenal Androgens for Correcting Cortisol Lateralization in Adrenal Venous Sampling in Patients with Normal Cortisol Secretion

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Wenjing Zhang ◽  
Keying Zhu ◽  
Hongyun Li ◽  
Yan Zhang ◽  
Dalong Zhu ◽  
...  
Keyword(s):  
Adrenocorticotropic Hormone ◽  
Adrenal Venous Sampling ◽  
Cortisol Secretion ◽  
Venous Sampling ◽  
Adrenal Androgens ◽  
Wide Range ◽  
Adrenal Masses ◽  
The Mean ◽  
Positive Correlations ◽  
The Right

The management of patients with adrenocorticotropic hormone-independent Cushing’s syndrome and bilateral adrenal masses is challenging. Adrenal venous sampling (AVS) has been used to identify functional lesions in previous studies, but it is not always reliable. The present study aims to address the variability of cortisol in the adrenal veins of patients without excessive cortisol secretion and investigate the use of adrenal androgens to correct the cortisol lateralization ratio in AVS. Thirty-seven patients with primary aldosteronism underwent successful AVS. Patients with normal cortisol secretion exhibited a wide range of cortisol concentrations in the right (601-89, 400 nmol/l) and left (331-35, 300 nmol/l) adrenal veins. The median cortisol gradients between adrenal venous and peripheral venous samples were 15.25 and 10.14 in the right and left sides, respectively, and the cortisol lateralization ratio (high side to low side) was as high as 9.49 (median 1.54). The mean plasma levels of cortisol in the adrenal venous and peripheral venous samples decreased from t-15 to t0. Significant positive correlations were observed between the cortisol concentrations and both androstenedione and dehydroepiandrosterone concentrations in the right and left adrenal veins. After correcting for androstenedione or dehydroepiandrosterone levels, the cortisol lateralization ratio was less than 2 in most adrenal venous samples. The present study demonstrated the wide variation in cortisol concentrations in the adrenal veins of patients with normal cortisol secretion. The adrenal androgens might be ideal analytes used as normalizers when assessing the cortisol lateralization of AVS in normal or hypercortisolism cases.

Pituitary Adrenal Responsiveness to Corticotropin-Releasing Hormone in Chronic Uremic Patients

1990 ◽  
Vol 10 (2) ◽  
pp. 153-156 ◽  
Author(s):  
Kostas C. Siamopoulos ◽  
Mathew Dardamanis ◽  
Despina Kyriaki ◽  
Michael Pappas ◽  
George Sferopoulos ◽  
...  
Keyword(s):  
Chronic Stress ◽  
Adrenocorticotropic Hormone ◽  
Acute Administration ◽  
Cortisol Response ◽  
Corticotropin Releasing Hormone ◽  
Plasma Acth ◽  
Normal Response ◽  
Releasing Hormone ◽  
Uremic Patients ◽  
Pituitary Adrenal Axis

We investigated the effect of exogenous ovine corticotropin-releasing hormone (oCRH) on plasma levels of adrenocorticotropic hormone (ACTH) and cortisol in 24 chronic renal failure patients: 8 nondialysis (NDCRF), 8 on hemodialysis (HD), and 8 on continuous ambulatory peritoneal dialysis (CAPD). In all groups the acute administration of oCRH caused a further increase (less pronounced in NDCRF patients) in the already elevated levels of cortisol. Following oCRH administration, plasma ACTH rose significantly in CAPD patients, but there was a blunted response of the hormone in the NDCRF and HD groups. The patterns of the ACTH and cortisol response in the last two groups, resemble those observed in chronic stress. We conclude that the hypothalamic-pituitary-adrenal axis in chronic uremic patients, retains the ability to respond to exogenous oCRH. Patients on CAPD, however, display a better, identical to normal response, which can be due to less chronic stress andlor to the more effective clearance of uremic toxins.

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