Metabolic actions of cortisol in a macropodid marsupial Thylogale billardierii

1988 ◽  
Vol 116 (1) ◽  
pp. 71-79 ◽  
Author(s):  
I. K. Martin ◽  
I. R. McDonald
Keyword(s):  
Food Intake ◽  
Urinary Excretion ◽  
Plasma Concentrations ◽  
Control Level ◽  
Amino Nitrogen ◽  
Metabolic Clearance ◽  
Control Value ◽  
Nitrogen Ratio ◽  
Mean Glucose ◽  
Urea Recycling

ABSTRACT In undisturbed pademelon wallabies (Thylogale billardierii) with indwelling jugular venous catheters, an increase in the plasma cortisol concentration from 0.25±0.05 to 1.35±0.15 (s.e.m.) μmol/l in 2 h, during i.v. infusion of cortisol at 1.0 mg/kg per h, caused no significant change in the plasma glucose concentration from the control value of 4.26±0.25 mmol/l. The rates of appearance (Ra) and metabolic clearance (MCR) of glucose, measured by steady-state isotope dilution, also did not change significantly from the control values of 14.9±0.7 μmol/kg per min and 3.52±0.19 ml/kg per min respectively. Twice-daily i.m. injections of 7 mg cortisol/kg for 7 days caused increases in plasma concentrations of cortisol, from 0.26±0.02 to 0.66±0.04 μmol/l on day 7, and glucose, from 5.1±0.1 to 7.2±0.6 mmol/l by day 5. The concentration of glycogen in the liver of wallabies fasted for 24 h increased from the control level of 1.17±0.56 to 5.92±1.14 g/100 g on day 7 (P<0.01), but mean glucose Ra and MCR did not change significantly. Plasma concentrations of α-amino nitrogen rose from 2.73±0.13 to 3.22±0.12 mmol/l on day 1 and remained at this level. Plasma concentrations of urea rose from 8.59±0.62 to 9.70±0.32 mmol/l on day 1, but then declined below the control level. Food intake and urinary excretion of nitrogen did not change in undisturbed animals. However, fasting followed by liver biopsy was accompanied by urinary excretion of nitrogen in excess of food intake, persisting until day 2 of treatment. The transient effect of cortisol on the plasma concentration of urea and lack of effect on urinary excretion of nitrogen could be explained by urea recycling, as indicated by a low urinary urea nitrogen: total nitrogen ratio and failure to excrete more than a mean of 26% of infused urea. It is concluded that cortisol has no short-term effect on carbohydrate metabolism in this marsupial. In the long term it can increase hepatic carbohydrate reserves through utilization of tissue amino nitrogen, the resulting urea being conserved by recycling. J. Endocr. (1988) 116, 71–79

Evidence that inhibin is an important factor in the regulation of FSH secretion during the mid-luteal phase in cows

1993 ◽  
Vol 136 (1) ◽  
pp. 35-41 ◽  
Author(s):  
H. Kaneko ◽  
Y. Nakanishi ◽  
K. Taya ◽  
H. Kishi ◽  
G. Watanabe ◽  
...  
Keyword(s):  
Luteal Phase ◽  
Plasma Concentrations ◽  
Control Level ◽  
Follicular Development ◽  
Abrupt Decrease ◽  
Control Value ◽  
Physiological Importance ◽  
Control Serum ◽  
High Concentrations ◽  
Inhibitory Regulation

ABSTRACT To investigate the physiological importance of inhibin in the regulation of FSH secretion in cows, seven cyclic cows were treated with an inhibin antiserum raised against bovine 32 kDa inhibin in a castrated goat. The same animals treated with a castrated goat serum (control serum) served as controls. On day 12 of the oestrous cycle (day 0 = day of oestrus), four of seven cows were injected with 100 ml inhibin antiserum first, and the remaining three cows with 100 ml control serum first. Twelve days after the second oestrus following the first serum injection (42–46 days after the first serum injection), the former four cows were injected with control serum and the latter three with inhibin antiserum. Follicular development after the injections of control serum or inhibin antiserum was assessed by daily ultrasonographic examination. Treatment with inhibin antiserum resulted in a marked increase (P < 0·01) in plasma concentrations of FSH and oestradiol-17β but not LH or progesterone, compared with those after treatment with control serum. Plasma concentrations of FSH increased significantly (P < 0·01) at 8 h after injection of antiinhibin serum when compared with the control value. Concentrations of FSH in the plasma remained high for 72 h, then declined to the control level by 84 h, concomitant with an abrupt decrease in the titre of free inhibin antibody in the plasma. High concentrations of oestradiol-17β were observed between 36 and 96 h after treatment. Treatment with inhibin antiserum markedly increased the number of small (≥ 4 < 7 mm in diameter), medium (≥ 7 < 10 mm) and large (≥ 10 mm) follicles by 48, 72 and 96 h after treatment when compared with the value before treatment. The number of large follicles returned to the pretreatment value at 168 h, whereas the number of small and medium follicles remained increased. The present results provide strong evidence that inhibin is an important factor in the inhibitory regulation of FSH secretion during the mid-luteal phase of cows, and demonstrate that an increase in endogenous FSH secretion after immunoneutralization of circulating inhibin stimulates the rapid growth of a large number of follicles. Journal of Endocrinology (1993) 136, 35–41

Comparison of Specific Antibody, D-Phe-Pro-Arg-CH2Cl and Aprotinin for Prevention of In Vitro Effects of Recombinant Tissue-Type Plasminogen Activator on Haemostasis Parameters

1987 ◽  
Vol 58 (03) ◽  
pp. 921-926 ◽  
Author(s):  
E Seifried ◽  
P Tanswell
Keyword(s):  
Specific Antibody ◽  
Plasma Concentrations ◽  
Fibrinolytic Therapy ◽  
Tissue Type ◽  
Control Value ◽  
Type Plasminogen Activator ◽  
In Vitro Effects ◽  
Fibrinolytic Parameters

SummaryIn vitro, concentration-dependent effects of rt-PA on a range of coagulation and fibrinolytic assays in thawed plasma samples were investigated. In absence of a fibrinolytic inhibitor, 2 μg rt-PA/ml blood (3.4 μg/ml plasma) caused prolongation of clotting time assays and decreases of plasminogen (to 44% of the control value), fibrinogen (to 27%), α2-antiplasmin (to 5%), FV (to 67%), FVIII (to 41%) and FXIII (to 16%).Of three inhibitors tested, a specific polyclonal anti-rt-PA antibody prevented interferences in all fibrinolytic and most clotting assays. D-Phe-Pro-Arg-CH2Cl (PPACK) enabled correct assays of fibrinogen and fibrinolytic parameters but interfered with coagulometric assays dependent on endogenous thrombin generation. Aprotinin was suitable only for a restricted range of both assay types.Most in vitro effects were observed only with rt-PA plasma concentrations in excess of therapeutic values. Nevertheless it is concluded that for clinical application, collection of blood samples on either specific antibody or PPACK is essential for a correct assessment of in vivo effects of rt-PA on the haemostatic system in patients undergoing fibrinolytic therapy.

ELIMINATION OF INFUSED ARGININE-VASOPRESSIN AND ITS LONG-ACTING DEAMINATED ANALOGUE IN RATS

1978 ◽  
Vol 78 (2) ◽  
pp. 179-186 ◽  
Author(s):  
DIANA GAZIS ◽  
W. H. SAWYER
Keyword(s):  
Arginine Vasopressin ◽  
Plasma Concentrations ◽  
Metabolic Clearance ◽  
Prolonged Infusion ◽  
Exponential Functions ◽  
Antidiuretic Effect ◽  
Long Acting ◽  
Deamino Arginine Vasopressin

SUMMARY Arginine-vasopressin (AVP) and deamino-arginine-vasopressin (dAVP) were infused into rats. When the concentrations of the two peptides were steady, the rate of clearance of AVP from the plasma was six times the rate of clearance of dAVP. Only 6% of the infused AVP was excreted unchanged in the urine, whereas approximately 100% of the dAVP was excreted. When the infusions were stopped, AVP disappeared from the plasma much more rapidly than dAVP. The plasma concentrations of the two peptides did not decay as simple exponential functions, suggesting that both AVP and dAVP entered a slowly exchanging compartment or compartments during prolonged infusion. These differences in the metabolic clearance of AVP and dAVP may well explain the prolonged antidiuretic effect of dAVP in rats.

Nutrient and bowel segment dependency of human intestinal control of gastric secretion

1982 ◽  
Vol 243 (5) ◽  
pp. G372-G376
Author(s):  
C. Owyang ◽  
L. J. Miller ◽  
J. R. Malagelada ◽  
V. L. Go
Keyword(s):  
Small Bowel ◽  
Acid Secretion ◽  
Control Level ◽  
Amino Nitrogen ◽  
Ileocecal Valve ◽  
Essential Amino Acids ◽  
Distal Segment ◽  
Nutrient Loads ◽  
Inhibited Acid ◽  
Different Levels

The gastric secretory effects of protein, fat, and carbohydrate infused at different levels of the small bowel were investigated in seven healthy subjects. Similar caloric loads (53.4 kcal) of protein (essential amino acids), lipid (oleic acid), and carbohydrate (glucose) in isomolar (280 mosmol/l) similar pH (7.4) solutions were infused into 60-cm segments of small bowel (isolated between two occlusive balloons), located distal to the ligament of Treitz (proximal), proximal to the ileocecal valve (distal), and between the two (middle). A submaximal gastric secretory background was provided by continuous intravenous pentagastrin. Protein stimulated acid secretion in the proximal (increase of 8.7 meq/h, representing 84 +/- 5% of control level) and middle (increase of 1.9 meq/h, representing 16 +/- 2% of control level) segments, while it inhibited acid secretion when infused into the distal segment (decrease of 3.7 meq/h, representing 33 +/- 4% of control level). In contrast, both lipid and carbohydrate inhibited acid secretion similarly (33-38% of control level) at all levels of the bowel. The different effects of protein at different levels of the bowel could not be explained by differences in serum gastrin, different degrees of absorption, or different postabsorptive levels of alpha-amino nitrogen. This suggests the presence of hormonal (nongastrin) or neural mechanisms in the proximal bowel to stimulate acid secretion and/or in the distal bowel to inhibit acid secretion. Thus, factors that determine specific nutrient loads to specific segments of bowel can have important physiological effects on gastric acid secretion.

ANDROGEN METABOLISM IN CONGENITAL ADRENAL HYPERPLASIA DUE TO 11 β-HYDROXYLASE DEFICIENCY

PEDIATRICS ◽  
1969 ◽  
Vol 44 (2) ◽  
pp. 201-208
Author(s):  
S. Douglas Frasier ◽  
Richard Horton ◽  
Robert A. Ulstrom
Keyword(s):  
Plasma Concentration ◽  
Urinary Excretion ◽  
Congenital Adrenal Hyperplasia ◽  
Conversion Ratio ◽  
Metabolic Clearance ◽  
Adrenal Hyperplasia ◽  
Metabolic Clearance Rate ◽  
Hydroxylase Deficiency ◽  
Glucocorticoid Administration

The plasma concentration of androstenedione and testosterone, metabolic clearance rate of androstenedione, and in vivo conversion ratio of androstenedione to testosterone have been studied in a normotensive 5-year-old female with congenital adrenal hyperplasia due to a deficiency of 11 β-hydroxylase. Prior to glucocorticoid administration, the urinary excretion of 17-ketosteroids varied from 2.2 to 4.9 mg/24 hours, urinary excretion of pregnanetriol varied from 0.7 to 2.2 mg/24 hours, and total 17-hydroxysteroid excretion varied from 1.2 to 7.5 mg/24 hours. Urinary tetrahydro-11-deoxy cortisol (TSH) was detected at a concentration of 550 µg/24 hours. The plasma concentration of androstenedione varied from 100 to 530 mµg/100 ml and the plasma concentration of testosterone varied from 40 to 90 mµg/100 ml. These values are significantly elevated when compared to those obtained in normal prepubertal females. Urinary steroid excretion and plasma androgen concentrations fell to normal in response to glucocorticoid administration. The metabolic clearance rate of androstenedione was 890 liters per day per M2 and the in vivo conversion ratio of androstenedione to testosterone was 11%. The calculated production rate of androstenedione was 4.7 mg per day per M2. Virilization in congenital adrenal hyperplasia due to 11 β-hydroxylase deficiency can be explained by an elevated plasma concentration of testosterone, which can be accounted for on the basis of conversion from androstenedione.

Cholecystokinin is a Satiety Hormone in Humans at Physiological Post-Prandial Plasma Concentrations

1995 ◽  
Vol 89 (4) ◽  
pp. 375-381 ◽  
Author(s):  
Anne Ballinger ◽  
Lorraine McLoughlin ◽  
Sami Medbak ◽  
Michael Clark
Keyword(s):  
Food Intake ◽  
Test Meal ◽  
Plasma Concentrations ◽  
Standard Test ◽  
Saline Infusion ◽  
Reduce Food Intake ◽  
Subsequent Test ◽  
Gut Hormone ◽  
Plasma Cholecystokinin ◽  
Satiety Hormone

1. Intravenous infusions of the brain/gut hormone, cholecystokinin, have been shown to reduce food intake in a subsequent test meal. However, in previous studies the doses administered were large and likely to have produced plasma concentrations far in excess of the normal post-prandial range. 2. In this study cholecystokinin-8 was infused intravenously to six healthy subjects in doses that reproduced physiological post-prandial concentrations. Plasma concentrations of cholecystokinin were measured using a novel sensitive and specific radioimmunoassay. The effect of cholecystokinin-8 infusion on subsequent food intake in a standard test meal was compared with the effect of saline infusion in the same subjects. 3. Food intake (mean ± SEM) was significantly less during cholecystokinin (5092 ± 665 kJ) than during saline infusion (6418 ± 723 kJ, P = 0.03). During cholecystokinin infusion, plasma concentrations increased from 0.45 ± 0.06 pmol/l to 7.28 ± 2.43 pmol/l immediately before the meal. With saline infusion there was no premeal increase in plasma cholecystokinin concentration. 4. This paper describes a novel radioimmunoassay for measurement of plasma concentrations of cholecystokinin. Using this assay we have demonstrated that cholecystokinin is important in control of satiety in humans.

scholarly journals Glucose-Induced Insulin Hypersecretion in Lipid-Infused Healthy Subjects Is Associated with a Decrease in Plasma Norepinephrine Concentration and Urinary Excretion

2001 ◽  
Vol 86 (10) ◽  
pp. 4901-4907 ◽  
Author(s):  
Christophe Magnan ◽  
Céline Cruciani ◽  
Laurence Clément ◽  
Pierre Adnot ◽  
Mylène Vincent ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Urinary Excretion ◽  
Healthy Subjects ◽  
Plasma Concentrations ◽  
Sympathetic Tone ◽  
Plasma Norepinephrine ◽  
C Peptide ◽  
Lipid Infusion ◽  
Hyperglycemic Clamp ◽  
Glucose Injection

We investigated the effect of a 48 h triglyceride infusion on the subsequent insulin secretion in response to glucose in healthy men. We measured the variations in plasma concentration and urinary excretion of catecholamines as an indirect estimation of sympathetic tone. For 48 h, 20 volunteers received a triglyceride/heparin or a saline solution, separated by a 1-month interval. At time 48 h, insulin secretion in response to glucose was investigated by a single iv glucose injection (0.5 g/kg−1) followed by an hyperglycemic clamp (10 mg·kg−1·min−1, during 50 min). The triglyceride infusion resulted in a 3-fold elevation in plasma free fatty acids and an increase in insulin and C-peptide plasma concentrations (1.5- and 2.5-fold, respectively, P &lt; 0.05), compared with saline. At time 48 h of lipid infusion, plasma norepinephrine (NE) concentration and urinary excretion levels were lowered compared with saline (plasma NE: 0.65 ± 0.08 vs. 0.42 ± 0.06 ng/ml, P &lt; 0.05; urinary excretion: 800 ± 70 vs. 620 ± 25 nmol/24 h, P &lt; 0.05). In response to glucose loading, insulin and C-peptide plasma concentrations were higher in lipid compared with saline infusion (plasma insulin: 600 ± 98 vs. 310 ± 45 pm, P &lt; 0.05; plasma C-peptide 3.5 ± 0.2 vs. 1.7 ± 0.2 nm, P &lt; 0.05). In conclusion, in healthy subjects, a 48-h lipid infusion induces basal hyperinsulinemia and exaggerated insulin secretion in response to glucose which may be partly related to a decrease in sympathetic tone.

Comparison of the feedback effect of magnesium and calcium on parathyroid hormone secretion in man

1987 ◽  
Vol 113 (1) ◽  
pp. 117-122 ◽  
Author(s):  
O. Ferment ◽  
P. E. Garnier ◽  
Y. Touitou
Keyword(s):  
Parathyroid Hormone ◽  
Urinary Excretion ◽  
Hormone Secretion ◽  
Plasma Concentrations ◽  
Magnesium Salt ◽  
Saline Injection ◽  
Molar Basis ◽  
Magnesium Salts ◽  
High Doses

ABSTRACT Administration of high doses of magnesium is known to produce a decrease in parathyroid hormone (PTH) secretion in human patients but the effect of magnesium on the secretion of PTH in healthy man is not known. We have looked at the effect of a relatively moderate i.v. dose of magnesium (7·08 mmol) in seven healthy men. In addition and for comparison the effect of calcium (4·25 mmol) was studied. Two magnesium salts were considered, magnesium sulphate (MgSO4) and magnesium pyrrolidone carboxylate (MgPC). Four i.v. injections were given at 08.00 h (MgPC, NaCl (control), MgSO4 and Ca gluconate), with an interval of 1 week between each injection. Whatever the magnesium salt the variations in plasma concentrations of magnesium were the same whereas no change in erythrocyte magnesium was observed. Plasma concentration of C-terminal PTH did not show significant variations after MgPC or saline injection. Both MgSO4 and Ca gluconate produced a statistically significant 30% decrease in plasma PTH levels 45 min after the injection. The effect was more sustained with calcium (2 h) than with magnesium (45 min). The urinary excretion of magnesium was significantly higher after injection of MgSO4 than after MgPC. These results suggest (1) that magnesium was, on a molar basis, less potent than calcium in regulating PTH secretion in vivo, (2) that the nature of the magnesium salt used must be kept in mind for the interpretation of the effect of magnesium on PTH secretion in vivo and (3) that the decrease in plasma PTH can partly explain the larger urinary excretion of magnesium after MgSO4 than after MgPC. J. Endocr. (1987) 113, 117–122

Metabolic clearance of angiotensin II in pregnant and nonpregnant sheep

1985 ◽  
Vol 249 (1) ◽  
pp. E49-E55 ◽  
Author(s):  
R. P. Naden ◽  
S. Coultrup ◽  
B. S. Arant ◽  
C. R. Rosenfeld
Keyword(s):  
Angiotensin Ii ◽  
Pressor Response ◽  
Plasma Concentrations ◽  
Metabolic Clearance ◽  
Ang Ii ◽  
Pressor Responses ◽  
Pregnant Sheep ◽  
Vascular Responsiveness ◽  
Arterial Plasma ◽  
In Pregnancy

Reduced vascular responsiveness to infused angiotensin II (ANG II) has been observed during pregnancy. It has been proposed that infusions produce lower circulating concentrations of ANG II in pregnancy, due to an increase in the metabolic clearance rate of ANG II (MCRangii). We have evaluated the MCRangii and the arterial plasma concentrations of ANG II during constant infusions of 1.15 micrograms ANG II/min into chronically instrumented pregnant (n = 6) and nonpregnant (n = 9) sheep. Although the pressor responses were significantly less in the pregnant than in the nonpregnant sheep (17.5 +/- 0.5 vs. 34.9 +/- 3.2 mmHg, P less than 0.001), the values for MCRangii were not different: 56.2 +/- 6.3 ml X min-1 X kg-1 in nonpregnant and 55.9 +/- 4.3 ml X min-1 X kg-1 in pregnant sheep. The steady-state plasma ANG II concentrations during the infusions were slightly less in pregnant than in nonpregnant sheep (388 +/- 36 vs. 454 +/- 36 pg/ml); however, this difference would be responsible for only a 2-mmHg reduction in the pressor response. We conclude that the reduced pressor response to infused ANG II in pregnancy is not due to an increase in MCRangii nor to lower plasma ANG II concentrations.

scholarly journals Effect of Lactic Acid Bacteria on the Pharmacokinetics and Metabolism of Ginsenosides in Mice

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1496
Author(s):  
Ji-Hyeon Jeon ◽  
Jaehyeok Lee ◽  
Jin-Hyang Park ◽  
Chul-Haeng Lee ◽  
Min-Koo Choi ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Formation Rate ◽  
Plasma Concentrations ◽  
Control Level ◽  
In Vitro Fermentation ◽  
Fecal Recovery ◽  
Fermentation Test

This study aims to investigate the effect of lactic acid bacteria (LAB) on in vitro and in vivo metabolism and the pharmacokinetics of ginsenosides in mice. When the in vitro fermentation test of RGE with LAB was carried out, protopanaxadiol (PPD) and protopanaxadiol (PPD), which are final metabolites of ginsenosides but not contained in RGE, were greatly increased. Compound K (CK), ginsenoside Rh1 (GRh1), and GRg3 also increased by about 30%. Other ginsenosides with a sugar number of more than 2 showed a gradual decrease by fermentation with LAB for 7 days, suggesting the involvement of LAB in the deglycosylation of ginsenosides. Incubation of single ginsenoside with LAB produced GRg3, CK, and PPD with the highest formation rate and GRd, GRh2, and GF with the lower rate among PPD-type ginsenosides. Among PPT-type ginsenosides, GRh1 and PPT had the highest formation rate. The amoxicillin pretreatment (20 mg/kg/day, twice a day for 3 days) resulted in a significant decrease in the fecal recovery of CK, PPD, and PPT through the blockade of deglycosylation of ginsenosides after single oral administrations of RGE (2 g/kg) in mice. The plasma concentrations of CK, PPD, and PPT were not detectable without change in GRb1, GRb2, and GRc in this group. LAB supplementation (1 billion CFU/2 g/kg/day for 1 week) after the amoxicillin treatment in mice restored the ginsenoside metabolism and the plasma concentrations of ginsenosides to the control level. In conclusion, the alterations in the gut microbiota environment could change the ginsenoside metabolism and plasma concentrations of ginsenosides. Therefore, the supplementation of LAB with oral administrations of RGE would help increase plasma concentrations of deglycosylated ginsenosides such as CK, PPD, and PPT.

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