Adrenal gland 5′deiodinase activity (AG-5′d). Kinetic characterization and fractional turnover rate (FTr)

Endocrine ◽  
1995 ◽  
Vol 3 (5) ◽  
pp. 361-366 ◽  
Author(s):  
M. Luna ◽  
B. Anguiano ◽  
C. Valverde-R
Keyword(s):  
Adrenal Gland ◽  
Turnover Rate ◽  
Kinetic Characterization ◽  
Deiodinase Activity ◽  
Fractional Turnover

Glycerol metabolism in rabbits

1968 ◽  
Vol 46 (9) ◽  
pp. 1107-1114 ◽  
Author(s):  
Jean Himms-Hagen
Keyword(s):  
Turnover Rate ◽  
Glycerol Kinase ◽  
Rabbit Liver ◽  
Constant Infusion ◽  
Glycerol Dehydrogenase ◽  
Glycerol Metabolism ◽  
Utilization Rate ◽  
Glycerol Concentration ◽  
Glycerol Utilization ◽  
Fractional Turnover

The endogenous rate of glycerol production in rabbits was measured by several techniques: constant infusion of 1,3-14C-glycerol or 2-3H-glycerol or unlabeled glycerol; single injection of 1,3-14C-glycerol or 2-3H-glycerol or unlabeled glycerol. The rate was 5.5–11.6 μmoles/kg per minute (9 rabbits). The mean fractional turnover rate was 0.0585 ± 0.0052. During infusion of noradrenaline together with 3H-glycerol, the fractional turnover rate was no different from that in the absence of noradrenaline. The maximum utilization rate of glycerol was 28.1 ± 1.40 μmoles/kg per minute. The glycerol space was 58.1% of body weight. The relationship of glycerol concentration to rate of glycerol utilization in the intact rabbit suggests the existence of an enzyme with a KM for glycerol of 0.33 × 10−3 M; the glycerol kinase of rabbit liver was found to have a KM for glycerol of 0.29 × 10−3 M. This enzyme could account for the disappearance of glycerol in the intact animal except that its Vmax is only 4% of that expected. Possible reasons for this are discussed. A glycerol dehydrogenase with a Vmax similar to that of the glycerol kinase also exists in rabbit liver; its KM for glycerol is so high (0.5 M) that it is unlikely to play a significant role in glycerol metabolism in the normal rabbit.

scholarly journals GAMMA GLOBULIN TURNOVER IN RABBITS BEFORE AND DURING HYPERIMMUNIZATION

1964 ◽  
Vol 119 (4) ◽  
pp. 537-546 ◽  
Author(s):  
Stig Bryde Andersen ◽  
Mogens Bjørneboe
Keyword(s):  
Turnover Rate ◽  
Gamma Globulin ◽  
Order Process ◽  
First Order ◽  
Plasma Pool ◽  
Fractional Turnover

The turnover of 131I-labeled gamma globulin has been determined in rabbits before and during (8 weeks later) hyperimmunization with pneumococcic vaccine, which increased the gamma globulin concentration 5 to 10 times. Before immunization fractional turnover rate was an average of 36 per cent of the plasma pool per day, and the rate of catabolism was 133 mg/kg/day. During hyperimmunization fractional turnover rate was an average of 37 per cent per day, and the rate of catabolism was 1160 mg/kg/day. The observation that the fractional turnover rate is independent of the concentration suggests that the rate of breakdown should have the characteristic of a first order process.

A theory for the quantification of transcapillary exchange by tracer-dilution curves

1964 ◽  
Vol 207 (1) ◽  
pp. 162-168 ◽  
Author(s):  
Pablo Martin ◽  
David Yudilevich
Keyword(s):  
Experimental Data ◽  
Turnover Rate ◽  
Mathematical Formulation ◽  
Indicator Dilution ◽  
Capillary Barrier ◽  
Dog Heart ◽  
Tracer Dilution ◽  
Isolated Dog Heart ◽  
Fractional Turnover ◽  
Dilution Curves

A mathematical formulation of the simultaneously obtained indicator-dilution curves of two tracers: one confined to plasma and another diffusible through the capillary barrier, is made. The procedure allows the estimation for the permeable substance of the fractional extraction from the blood, and the interstitial fractional turnover rate and compartment size. The experimental data is obtained in 3–4 min in isolated perfused organs. Na22 (NaCl) and siderophilin-Fe59 first circulation dilution curves obtained in the isolated dog heart are used to exemplify the procedure.

Dietary iodine and accumulation of radioiodine in thyroids of chickens.

1978 ◽  
Vol 234 (2) ◽  
pp. E168 ◽  
Author(s):  
W S Newcomer
Keyword(s):  
Growth Rates ◽  
Half Life ◽  
Trichloroacetic Acid ◽  
Turnover Rate ◽  
Iodine Content ◽  
White Leghorn ◽  
General Terms ◽  
Binding Rate ◽  
Wide Range ◽  
Fractional Turnover

Groups of hatchling white leghorn cockerels were fed a basic, semisynthetic low-iodine diet to which various amounts of iodide were added: 0 up to 100 microgram I/g feed. Growth rates were unaffected by the range of dietary iodine content. A transitory goiter occurred only in the group fed the basic low-I diet. Half-life of 131I in the thyroid increased directly and fractional turnover rate inversely with increase of dietary iodine. Trichloroacetic acid-soluble iodine in serum did not accurately reflect variation of dietary iodine. However, effective clearance and binding rate constants did decrease proportionally to dietary iodine increase beyond the first 3-5 days. Concentration of iodine in thyroid was directly proportional to dietary iodine after 10 days. There was no consistent correlation between thyroxine or triiodothyronine and dietary iodine except in general terms of high and low dietary iodine groups. The avian thyroid exhibits great lability in adjusting functionally to a wide range of dietary iodine contents.

Studies of human zinc kinetics using the stable isotope 70Zn

1993 ◽  
Vol 84 (1) ◽  
pp. 113-117 ◽  
Author(s):  
N. M. Lowe ◽  
A. Green ◽  
J. M. Rhodes ◽  
M. Lombard ◽  
R. Jalan ◽  
...  
Keyword(s):  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Turnover Rate ◽  
Kinetic Studies ◽  
Normal Subjects ◽  
Short Term ◽  
Control Subjects ◽  
Two Component ◽  
Kinetics Of ◽  
Fractional Turnover

1. The short-term (120 min) kinetics of Zn turnover has been studied in control subjects and patients with alcoholic liver disease after intravenous injection of 0.5 mg of 96.5% enriched 70ZnCl2. 2. The 70Zn enrichment of plasma was found closely to obey two-compartment kinetics and the derived two-component decay equation has been used to calculate the size and turnover of the initial two rapidly exchanging pools of body Zn. 3. In normal subjects isotopic Zn appears initially to equilibrate with the whole of the plasma Zn which comprises the first metabolic compartment, pool a. This has a size of 0.72 ± 0.1 μmol/kg. 70Zn equilibration then occurs with a second compartment, pool b, consistent with a rapidly exchanging liver Zn pool of size 3.60 ± 0.93 μmol/kg. The fractional turnover rate of pool b was found to be fivefold slower than that of pool a. 4. In the alcoholic group an expansion of pool a was observed (1.63 ± 0.39 μmol/kg), but the size of the second pool was not significantly different from that of control subjects (5.55 ± 1.0 μmol/kg), although its fractional turnover was significantly increased (Kab: control subjects, 0.018 ± 0.002 min−1, alcoholic patients, 0.031 ± 0.006 min−1). 5. These data therefore demonstrate that kinetic studies using stable isotopes of Zn can provide novel information on exchangeable Zn pools in man, but provide no support for the possibility of an underlying Zn depletion in patients with alcoholic liver disease.

Neuroendocrine regulation of adrenal gland and hypothalamus 5'deiodinase activity. II. Effects of splanchnicotomy and hypophysectomy.

Endocrinology ◽  
1995 ◽  
Vol 136 (8) ◽  
pp. 3346-3352 ◽  
Author(s):  
B Anguiano ◽  
A Quintanar ◽  
M Luna ◽  
L Navarro ◽  
A Ramírez del Angel ◽  
...  
Keyword(s):  
Adrenal Gland ◽  
Neuroendocrine Regulation ◽  
Deiodinase Activity

75SeHCAT fractional turnover rate in primary biliary cirrhosis

1993 ◽  
Vol 5 (12) ◽  
pp. 1037-1042 ◽  
Author(s):  
Mario Fracchia ◽  
Riccardo Pellerito ◽  
Roberto Ferraris ◽  
Paola Secreto ◽  
Alessandro Favero ◽  
...  
Keyword(s):  
Primary Biliary Cirrhosis ◽  
Turnover Rate ◽  
Biliary Cirrhosis ◽  
Fractional Turnover

scholarly journals Estimation of the proportion of non-ammonia-nitrogen reaching the lower gut of the ruminant derived from bacterial and protozoal nitrogen

1982 ◽  
Vol 48 (2) ◽  
pp. 417-431 ◽  
Author(s):  
W. D. Steinhour ◽  
M. R. Stokes ◽  
J. H. Clark ◽  
J. A. Rogers ◽  
C. L. Davis ◽  
...  
Keyword(s):  
Turnover Rate ◽  
Single Injection ◽  
Rumen Fluid ◽  
Ammonia Nitrogen ◽  
N Turnover ◽  
Large Pool ◽  
Small Pool ◽  
N Enrichment ◽  
Infusion Period ◽  
Fractional Turnover

1. A method for estimating the proportions of bacterial- and protozoal-N in the total non-ammonia-N reaching the lower gut of the ruminant under steady-state conditions was evaluated. Three trials using two different diets were conducted with a Holstein steer equipped with a rumen cannula and duodenal re-entrant cannulas.2. An intraruminal primed infusion of (15nh4)2so4was administered for 68 h during each trial. Bacteria and protozoa samples were isolated from rumen fluid at approximately 6 h intervals during each infusion period. Total non-ammonia-N was isolated from duodenal digesta samples taken at approximately the same times. All of these samples were analysed for15N enrichment. A computer program was used to fit equations to the15N-enrichment curves of bacterial- and protozoal-N. Models of both bacterial- and protozoal-N kinetics consisted of a small pool which equilibrated rapidly with rumen NH3and a large pool with a fractional turnover rate of 0.045–0.070/h for bacterial-N and 0.056–0.069/h for protozoal-N.3. Abomasal fluid turnover was estimated by a single injection of polyethylene glycol (molecular weight 4000) into the rumen followed by sampling of rumen fluid and duodenal digesta.4. Estimates of abomasal fluid turnover, bacterial-N turnover, and protozoal-N turnover were entered into an equation which was adjusted by computer iteration to fit the15n-enrichment curve of duodenal digesta non-NH3-N generated from each (15nh4)2so4infusion period. The computer fit of this equation to the observed results gave estimates of 0.39–0.45 and 0.22–0.41 for the proportion of duodenal non-NH3-N derived from bacterial-N and protozoal-N respectively.5. This method is potentially useful in estimating microbial protein passage to the lower gut in ruminants. Sampling digesta from the omasum rather than the duodenum would simplify the method and possibly increase the reliability of the estimates.

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