Dissociation of pituitary glycoprotein response to releasing hormones in chronic renal failure

1980 ◽  
Vol 93 (3) ◽  
pp. 277-282 ◽  
Author(s):  
Derek LeRoith ◽  
Gabriel Danovitz ◽  
Stefan Trestian ◽  
Irving M. Spitz
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Clearance Rate ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Glycoprotein Hormone ◽  
The Third ◽  
Hormone Responses ◽  
Tsh Levels

Abstract. The LH, FSH and TSH response to LRH and TRH has been evaluated in patients with chronic renal failure. Basal gonadotrophins were elevated in 3 out of 6 males; one of 4 pre-menopausal females had increased basal LH. Exaggerated LH responses to LRH were noted in 4 out of 6 males and one of 4 females; FSH responses were increased in 3 of these males. One male and one female had attenuated LH and FSH responses to LRH. Both testosterone and oestradiol levels were reduced. In 5 out of 6 subjects tested both pre- and post-dialysis there was a greater LH and FSH response to LRH following dialysis. This suggests the presence of a dialysable toxin which is inhibiting the gonadotrophin response to LRH. Gonadotrophin levels remained elevated during 4 h of dialysis suggesting prolongation of the metabolic clearance rate. Despite low T3 levels, TSH response to TRH (200 μg) was only elicited in 2 of 6 cases. However, all 3 responded to 500 μg and 2 out of 3 to 1000 μg TRH, the third showing an attenuated response. TSH levels also remained persistently elevated in the responders. Dialysis however, failed to improve the relative TSH non-responsiveness to TRH. In conclusion the data has shown that there is a dissociation in glycoprotein hormone responses to releasing hormones in uraemia. Whereas the gonadotrophs retain their responsiveness to LRH, the thyrotrophs appear to be more effected by the uraemic process and demonstrate an impaired response to TRH.

Metabolic clearance rate of arginine vasopressin in severe chronic renal failure

1992 ◽  
Vol 83 (5) ◽  
pp. 583-587 ◽  
Author(s):  
Nicholas B. Argent ◽  
Robert Wilkinson ◽  
Peter H. Baylis
Keyword(s):  
Renal Failure ◽  
Steady State ◽  
Chronic Renal Failure ◽  
Arginine Vasopressin ◽  
Clearance Rate ◽  
Plasma Concentrations ◽  
Normal Subjects ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Plasma Arginine

1. The metabolic clearance rate of arginine vasopressin was determined using a constant infusion technique in normal subjects and patients with chronic renal failure immediately before commencing dialysis. Endogenous arginine vasopressin was suppressed in all subjects before the infusion with a water load. 2. Plasma arginine vasopressin concentrations were determined using a sensitive and specific radioimmunoassay after Florisil extraction. The detection limit of the assay was 0.3 pmol/l, and intra- and inter-assay coefficients of variation at 2 pmol/l were 9.7% and 15.3%, respectively. 3. In normal subjects, the metabolic clearance rate was determined at two infusion rates producing steady-state concentrations of arginine vasopressin of 1.3 and 4.4 pmol/l. In the patients with renal failure, a single infusion rate was used, producing a steady-state concentration of 1.5 pmol/l. 4. At comparable plasma arginine vasopressin concentrations, metabolic clearance rate was significantly reduced in patients with renal failure (normal 1168 ± 235 ml/min versus renal failure 584 ± 169 ml/min; means ± sd; P<0.001). 5. Free water clearance was significantly reduced in normal subjects during the arginine vasopressin infusion from 8.19 ± 2.61 to −1.41 ± 0.51 ml/min (P<0.001), but was unchanged in the patients with renal failure after attaining comparable plasma arginine vasopressin concentrations. 6. In normal subjects there was a small but significant fall in metabolic clearance rate at the higher steady-state arginine vasopressin concentration (1168 ± 235 ml/min at 1.3 pmol/l versus 1059 ± 269 ml/min at 4.4 pmol/l; P = 0.016). 7. Our results show that the metabolic clearance rate of arginine vasopressin is reduced by approximately 50% in severe chronic renal failure. This alone may account for the raised plasma concentrations of the hormone seen in this condition.

Mechanism of decreased calcitriol degradation in renal failure

1992 ◽  
Vol 262 (2) ◽  
pp. F192-F198 ◽  
Author(s):  
C. H. Hsu ◽  
S. R. Patel ◽  
E. W. Young
Keyword(s):  
Renal Failure ◽  
Binding Affinity ◽  
Clearance Rate ◽  
Uremic Toxins ◽  
Metabolic Clearance ◽  
Receptor Complex ◽  
Nuclear Chromatin ◽  
Disappearance Rate ◽  
Metabolic Clearance Rate ◽  
Plasma Ultrafiltrate

Metabolic clearance rate (MCR) of calcitriol is decreased in renal failure, and uremic toxins play a major role in the suppression of calcitriol degradation. In this experiment, we studied the effect of uremic toxins on renal 24- and 26-hydroxylase (HX) activities. Normal rats were infused for 20 h with 30 ml of normal or uremic plasma ultrafiltrates. At the end of infusion, renal enzymes activities were measured by the generations of 1,24,25- and 1,25,26-trihydroxyvitamin D3 10 min after the addition of 25 nM or 1 microM calcitriol. Renal 24-HX activity decreased approximately 50%, whereas 26-HX activity did not decrease in rats infused with uremic plasma ultrafiltrate. The induction of 24-HX activity by 100 ng calcitriol also decreased in rats infused with uremic ultrafiltrate. To examine whether uremic ultrafiltrate could directly inhibit the degradation enzymes, 24- and 26-HX activities were measured in kidney homogenates preincubated for 3 h with either normal or uremic ultrafiltrate. Uremic ultrafiltrate did not directly suppress 24- and 26-HX activities. Furthermore, the disappearance rate of calcitriol was similar for 90 min in kidney homogenates after they were preincubated for 3 h with uremic and normal ultrafiltrates. Because 24-HX synthesis is induced by the calcitriol-receptor complex binding to nuclear chromatin and activating genes coding for the enzyme, we studied the effect of uremic toxins on the binding affinity of calcitriol-receptor complex for DNA-cellulose. Uremic ultrafiltrate significantly reduced the binding affinity of the hormone receptor complex for DNA when the receptor was preincubated with the ultrafiltrate for 3 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma clearance and effects of alpha-hANP infused in patients with end-stage renal failure

1988 ◽  
Vol 254 (6) ◽  
pp. F895-F899 ◽  
Author(s):  
G. Tonolo ◽  
M. McMillan ◽  
J. Polonia ◽  
A. Pazzola ◽  
P. Montorsi ◽  
...  
Keyword(s):  
Renal Failure ◽  
Clearance Rate ◽  
Half Life ◽  
Study Phase ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
End Stage Renal Failure ◽  
Normal Volunteers ◽  
End Stage ◽  
Plasma Half Life

The effects and clearance of synthetic atrial natriuretic peptide (alpha-hANP) were investigated in eight patients with end-stage renal failure and six normal volunteers. ANP or vehicle was infused for 1 h at 10 pmol.kg-1.min-1 in random order on two separate occasions. During ANP infusions in end-stage renal patients, microhematocrit rose by 9.8 +/- 2% (P less than 0.005, n = 8), from base-line values of 0.24 +/- 0.02. Serum protein and albumin rose consistently. In contrast, during placebo infusions, no significant changes were seen. Blood pressure, heart rate, plasma renin concentration, serum creatinine, and electrolytes did not change significantly during either study phase. In end-stage renal failure patients, metabolic clearance rate of infused ANP was 1.04 +/- 0.095 l/min and its plasma half-life was 4 min 34 s. In normal volunteers, metabolic clearance rate was 2.6 l/min and its plasma half-life 3 min 30 s. The data suggest that ANP promotes contraction of plasma volume via a mechanism independent of renal function and also indicate that the kidney is not the only organ involved in the ANP metabolism.

Comparative metabolic clearance rate, volume of distribution and plasma half-life of human β-lipotropin and acth

Life Sciences ◽  
1978 ◽  
Vol 23 (23) ◽  
pp. 2323-2330 ◽  
Author(s):  
Anthony S. Liotta ◽  
Choh Hao Li ◽  
George C. Schussler ◽  
Dorothy T. Krieger
Keyword(s):  
Clearance Rate ◽  
Half Life ◽  
Volume Of Distribution ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Plasma Half Life

scholarly journals The Renin-Angiotensin System in Conscious Newborn Sheep: Metabolic Clearance Rate and Activity

2007 ◽  
Vol 61 (6) ◽  
pp. 681-686 ◽  
Author(s):  
Sithembiso C Velaphi ◽  
Kevin Despain ◽  
Timothy Roy ◽  
Charles R Rosenfeld
Keyword(s):  
Clearance Rate ◽  
Renin Angiotensin System ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Angiotensin System ◽  
Renin Angiotensin

Validation of a new method for determination of free fatty acid turnover

1987 ◽  
Vol 252 (3) ◽  
pp. E431-E438 ◽  
Author(s):  
J. M. Miles ◽  
M. G. Ellman ◽  
K. L. McClean ◽  
M. D. Jensen
Keyword(s):  
Steady State ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Clearance Rate ◽  
Experimental Period ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
State Equations ◽  
Tracer Methods

The accuracy of tracer methods for estimating free fatty acid (FFA) rate of appearance (Ra), either under steady-state conditions or under non-steady-state conditions, has not been previously investigated. In the present study, endogenous lipolysis (traced with 14C palmitate) was suppressed in six mongrel dogs with a high-carbohydrate meal 10 h before the experiment, together with infusions of glucose, propranolol, and nicotinic acid during the experimental period. Both steady-state and non-steady-state equations were used to determine oleate Ra ([3H]oleate) before, during, and after a stepwise infusion of an oleic acid emulsion. Palmitate Ra did not change during the experiment. Steady-state equations gave the best estimates of oleate inflow approximately 93% of the known oleate infusion rate overall, while errors in tracer estimates of inflow were obtained when non-steady-state equations were used. The metabolic clearance rate of oleate was inversely related to plasma concentration (P less than 0.01). In conclusion, accurate estimates of FFA inflow were obtained when steady-state equations were used, even under conditions of abrupt and recent changes in Ra. Non-steady-state equations, in contrast, may provide erroneous estimates of inflow. The decrease in metabolic clearance rate during exogenous infusion of oleate suggests that FFA transport may follow second-order kinetics.

Glucagon and insulin metabolism in a portal-hypertensive rat model

1987 ◽  
Vol 253 (2) ◽  
pp. G110-G115 ◽  
Author(s):  
E. Sikuler ◽  
J. Polio ◽  
R. J. Groszmann ◽  
R. Hendler
Keyword(s):  
Portal Vein ◽  
Rat Model ◽  
Clearance Rate ◽  
Portal Blood Flow ◽  
Portal System ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Insulin Metabolism ◽  
Portosystemic Shunting ◽  
Glucagon And Insulin

The role that portosystemic shunting plays in inducing the alterations of glucagon and insulin metabolism, which are observed in chronic liver disease, was studied in a rat model of prehepatic portal hypertension induced by portal vein constriction. Net splanchnic output of the hormones into the portal circulation was calculated from the difference between portal and systemic concentrations multiplied by portal plasma flow. Metabolic clearance rate was calculated as the ratio between output and systemic concentration. Portal blood flow was measured by the radioactive microsphere technique. Glucagon output in the portal vein-ligated rats was higher than in the sham-operated controls (5.9 +/- 1.5 vs. 2.0 +/- 0.2 ng/min, P less than 0.05). The metabolic clearance rate of glucagon was not significantly different between the two groups. Insulin output was not significantly different between the two groups; however, the metabolic clearance rate of insulin in the portal vein-ligated rats was reduced in comparison with the sham-operated group (9.5 +/- 1.5 vs. 18.4 +/- 3.3 ml/min, P less than 0.05). Our results indicate that portosystemic shunting per se is sufficient to cause an increased splanchnic output of glucagon into the portal system and a decreased metabolic clearance of insulin.

Production rate, metabolic clearance rate and blood concentration of progesterone in conscious and anaesthetized pregnant rats

1984 ◽  
Vol 102 (3) ◽  
pp. 357-363 ◽  
Author(s):  
B. J. Waddell ◽  
N. W. Bruce
Keyword(s):  
Production Rate ◽  
Clearance Rate ◽  
Blood Concentration ◽  
Constant Infusion ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Short Term ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Anaesthetized Rats

ABSTRACT Both production rate and metabolic clearance rate (MCR) of progesterone may vary rapidly and so effect short-term changes in blood concentration of the hormone. Here, a constant infusion and sampling technique was used to estimate these three characteristics of progesterone metabolism in seven conscious and ten anaesthetized rats on day 16 of pregnancy. After steady state was achieved, four samples were collected during a 1-h period from each rat. Mean values for production rate and MCR of progesterone in conscious rats were 14·0 ±1·4 μmol/day and 63·2 ± 6·2 litres/day respectively. Both values were substantially reduced in anaesthetized rats (8.6 ±0·8 μmol/ day and 39·4± 3·4 litres/day respectively) and so blood concentration was unchanged. The production rate was positively related to the total mass of luteal tissue (common correlation coefficient, r = 0·61, P <0·05). There were no consistent changes in the three characteristics with time but variation within rats was high. The estimated coefficients of variation for production rate, MCR and blood concentration within rats were 26, 18 and 17% in conscious and 27, 20 and 23% in anaesthetized rats respectively. Short-term changes in production rate and MCR generally were in the same direction (P <0·05). This reduced variation in blood concentration which would otherwise have occurred if production rate and MCR were unrelated. The pregnant rat is clearly capable of rapid shifts in production rate, MCR and blood concentration of progesterone and the positive relationship between production rate and MCR has a homeostatic effect on blood concentration. J. Endocr. (1984) 102, 357–363

Sign in / Sign up

Export Citation Format

Share Document