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.

Glycerol metabolism in Rhizobium

1976 ◽  
Vol 22 (2) ◽  
pp. 150-153 ◽  
Author(s):  
A. Arias ◽  
G. Martinez-Drets
Keyword(s):  
Metabolic Pathway ◽  
Glycerol Kinase ◽  
Rhizobium Japonicum ◽  
Glycerol Dehydrogenase ◽  
Glycerol Metabolism ◽  
Glycerophosphate Dehydrogenase ◽  
Slow Growing

Four strains of Rhizobium japonicum and one strain of R. trifolii were grown on glycerol and found to contain a soluble ATP-glycerol kinase and a particulate glycerophosphate dehydrogenase. Both enzymes are induced by glycerol. The presence of NAD+– or NADP+–glycerol dehydrogenase was not detected in any of the strains. No significant differences were found in the glycerol metabolic pathway between fast- and slow-growing rhizobia.

scholarly journals Fermentative Utilization of Glycerol by Escherichia coli and Its Implications for the Production of Fuels and Chemicals

2007 ◽  
Vol 74 (4) ◽  
pp. 1124-1135 ◽  
Author(s):  
Abhishek Murarka ◽  
Yandi Dharmadi ◽  
Syed Shams Yazdani ◽  
Ramon Gonzalez
Keyword(s):  
Escherichia Coli ◽  
Anaerobic Fermentation ◽  
Glycerol Metabolism ◽  
Nuclear Magnetic Resonance Analysis ◽  
Glycerol Fermentation ◽  
Glycerol Utilization ◽  
Negative Effect ◽  
Balance Analysis ◽  
Fuels And Chemicals ◽  
High Degree

ABSTRACT Availability, low prices, and a high degree of reduction make glycerol an ideal feedstock to produce reduced chemicals and fuels via anaerobic fermentation. Although glycerol metabolism in Escherichia coli had been thought to be restricted to respiratory conditions, we report here the utilization of this carbon source in the absence of electron acceptors. Cells grew fermentatively on glycerol and exhibited exponential growth at a maximum specific growth rate of 0.040 ± 0.003 h−1. The fermentative nature of glycerol metabolism was demonstrated through studies in which cell growth and glycerol utilization were observed despite blocking several respiratory processes. The incorporation of glycerol in cellular biomass was also investigated via nuclear magnetic resonance analysis of cultures in which either 50% U-13C-labeled or 100% unlabeled glycerol was used. These studies demonstrated that about 20% of the carbon incorporated into the protein fraction of biomass originated from glycerol. The use of U-13C-labeled glycerol also allowed the unambiguous identification of ethanol and succinic, acetic, and formic acids as the products of glycerol fermentation. The synthesis of ethanol was identified as a metabolic determinant of glycerol fermentation; this pathway fulfills energy requirements by generating, in a redox-balanced manner, 1 mol of ATP per mol of glycerol converted to ethanol. A fermentation balance analysis revealed an excellent closure of both carbon (∼95%) and redox (∼96%) balances. On the other hand, cultivation conditions that prevent H2 accumulation were shown to be an environmental determinant of glycerol fermentation. The negative effect of H2 is related to its metabolic recycling, which in turn generates an unfavorable internal redox state. The implications of our findings for the production of reduced chemicals and fuels were illustrated by coproducing ethanol plus formic acid and ethanol plus hydrogen from glycerol at yields approaching their theoretical maximum.

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.

CHANGES IN UTILIZATION OF THYROID HORMONE AND THYROXINE DISTRIBUTION SPACE IN SHEEP TREATED WITH STILBOESTROL

1962 ◽  
Vol 25 (3) ◽  
pp. 283-291 ◽  
Author(s):  
A. ŚLEBODZIŃSKI
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Turnover Rate ◽  
Conversion Ratio ◽  
Utilization Rate ◽  
Distribution Space ◽  
Hormone Metabolism ◽  
Thyroid Hormone Metabolism ◽  
Small Doses ◽  
Increased Activity

SUMMARY 1. The effect of 250 μg./day stilboestrol on thyroid hormone metabolism in sheep has been investigated. 2. After 5 days the conversion ratio was significantly increased and the rate of release of iodine from the thyroid also rose. 3. After 40 days the thyroxine utilization rate increased but the turnover rate was reduced. This effect was presumably due to a coincident increase in the plasma protein-bound iodine and the thyroxine distribution space. 4. It is suggested that small doses of oestrogen decrease tissue metabolism, inducing increased activity of the thyroid gland and a compensatory increase in the peripheral utilization of thyroid hormone.

Relationship between turnover rate and blood concentration of lactate in exercising dogs

1975 ◽  
Vol 39 (2) ◽  
pp. 231-234 ◽  
Author(s):  
F. L. Eldridge
Keyword(s):  
Steady State ◽  
Blood Lactate ◽  
Turnover Rate ◽  
The Other ◽  
Constant Infusion ◽  
Blood Concentrations ◽  
Lactate Turnover ◽  
Anesthetized Dogs ◽  
Lactate Removal ◽  
The Relationship

Steady-state blood lactate concentrationss and lactate turnover, or entry, rates were determined by use of constant infusion of L(+)-[14C]lactate in seven anesthetized dogs before and during electrically induced exercise. Lactate entry rates increased during exercise in all dogs with or without the infusion of additional exogenous cold lactate. Blood lactate concentrations, on the other hand, rose to levels considerably below those predicted for these entry rates in a previous study of the relationship in normal nonexercising dogs. It is concluded that improved efficiency of lactate removal during exercise allows low blood concentrations despite large increases in entry rates.

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.

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