Metabolism of lactate by mature boar spermatozoa

1997 ◽  
Vol 9 (2) ◽  
pp. 227 ◽  
Author(s):  
A. R. Jones
Keyword(s):  
Lactate Dehydrogenase ◽  
Nicotinamide Adenine Dinucleotide ◽  
Energy Charge ◽  
High Energy ◽  
The Other ◽  
Glycolytic Metabolism ◽  
Lactate Transport ◽  
Lactate Dehydrogenase Isozymes ◽  
Charge Potential ◽  
Boar Spermatozoa

Boar sperm oxidatively metabolized fructose, glucose, glycerol, glycerol 3-phosphate and lactate to CO2 but pyruvate produced only small amounts of CO2 and this was almost completely prevented when endogenous glycolytic metabolism was inhibited. Lactate was the preferred substrate over fructose, glycerol and glycerol 3-phosphate and when lactate was offered in the presence of pyruvate, lactate was preferentially oxidized to CO2. The rate of oxidation of fructose, glycerol and glycerol 3-phosphate was approximately halved in the presence of equi-molar concentrations of lactate and the metabolism of lactate was progressively decreased in the presence of increasing concentrations of mersalyl, an inhibitor of lactate transport. Sperm maintained a high energy charge potential when incubated with lactate as substrate in the presence or absence of bromopyruvate, an inhibitor of endogenous glycolytic metabolism. This evidence confirms that it is lactate, rather than pyruvate, that enters the mitochondria thereby constituting a lactate–pyruvate transport system in these cells for regenerating cytoplasmic nicotinamide adenine dinucleotide (NAD +). Electrophoretic examination of the lactate dehydrogenase isozymes from sperm and several other tissues of the boar showed that sperm contained almost entirely an isozyme which was not present in the other tissues.

Substrates for endogenous metabolism by mature boar spermatozoa

Reproduction ◽  
2000 ◽  
pp. 129-135 ◽  
Author(s):  
AR Jones ◽  
WA Bubb
Keyword(s):  
Energy Charge ◽  
High Energy ◽  
Glycolytic Pathway ◽  
Membrane Phospholipids ◽  
Atp Production ◽  
Metabolic Studies ◽  
Metabolic Substrates ◽  
Charge Potential ◽  
Endogenous Compounds ◽  
Boar Spermatozoa

Washed boar spermatozoa incubated in the absence of exogenous substrates maintained a high energy charge potential (ECP) for at least 10 h. Addition of bromopyruvate, an inhibitor of stage 2 of the glycolytic pathway, at any time during the incubation caused an immediate decrease in the ECP, indicating that the mobilization of endogenous compounds requires this section of the pathway for the production of lactate, the major mitochondrial substrate for ATP production. Some of the sources of the metabolic substrates have been identified, by NMR and metabolic studies, as di- or triglycerides, to produce glycerol, and membrane phospholipids for the production of glycerol 3-phosphate. Acetylcarnitine contributes acetyl groups early in the incubation; glycerylphosphorylcholine is degraded to glycerol 3-phosphate and choline after about 5 h, and acetate also accumulates after about 5 h. The presence of phosphorylcholine and phosphorylethanolamine later in the incubation indicates that phospholipids are also degraded to glycerol.

Anaerobic energy provision in aged skeletal muscle during tetanic stimulation

1991 ◽  
Vol 70 (4) ◽  
pp. 1787-1795 ◽  
Author(s):  
C. B. Campbell ◽  
D. R. Marsh ◽  
L. L. Spriet
Keyword(s):  
Skeletal Muscle ◽  
Energy Demand ◽  
Energy Charge ◽  
High Energy ◽  
High Energy Phosphates ◽  
Fischer 344 ◽  
Charge Potential ◽  
Anaerobic Energy ◽  
Gastrocnemius Muscles

The effect of age on skeletal muscle anaerobic energy metabolism was investigated in adult (11 mo) and aged (25 mo) Fischer 344 rats. Hindlimb skeletal muscles innervated by the sciatic nerve were stimulated to contract with trains of supramaximal impulses (100 ms, 80 Hz) at a train rate of 1 Hz for 60 s, with an occluded circulation. Soleus, plantaris, and red and white gastrocnemius (WG) were sampled from control and stimulated limbs. All muscle masses were reduced with age (9-13%). Peak isometric tensions, normalized per gram of wet muscle, were lower throughout the stimulation in the aged animals (28%). The potential for anaerobic ATP provision was unaltered with age in all muscles, because resting high-energy phosphates and glycogen contents were similar to adult values. Anaerobic ATP provision during stimulation was unaltered by aging in soleus, plantaris, and red gastrocnemius muscles. In the WG, containing mainly fast glycolytic (FG) fibers, ATP and phosphocreatine contents were depleted less in aged muscle. In situ glycogenolysis and glycolysis were 90.0 +/- 4.8 and 69.3 +/- 2.6 mumol/g dry muscle (dm) in adult WG and reduced to 62.3 +/- 6.9 and 51.5 +/- 5.5 mumol/g dm, respectively, in aged WG. Consequently, total anaerobic ATP provision was lower in aged WG (224.5 +/- 20.9 mumol/g dm) vs. adult (292.6 +/- 7.6 mumol/g dm) WG muscle. In summary, the decreased tetanic tension production in aged animals was associated with a decreased anaerobic energy production in FG fibers. Reduced high-energy phosphate use and a greater energy charge potential after stimulation suggested that the energy demand was reduced in aged FG fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Inhibition of Fructolysis in Boar Spermatozoa by the Male Antifertility Agent (S)-a-Chlorohydrin

1982 ◽  
Vol 35 (6) ◽  
pp. 595 ◽  
Author(s):  
Denise Stevenson ◽  
A RJones
Keyword(s):  
Oxidative Metabolism ◽  
Inhibitory Activity ◽  
Energy Charge ◽  
Substrate Level Phosphorylation ◽  
Charge Potential ◽  
Substrate Level ◽  
Glyceraldehydephosphate Dehydrogenase ◽  
Fructose 1,6 Bisphosphate ◽  
Boar Spermatozoa

The (S)-isomer of the male antifertility agent IX-chlorohydrin strongly inhibited the oxidative metabolism of fructose by boar spermatozoa in vitro. The result of this action, which has been deduced to be an inhibition of glyceraldehydephosphate dehydrogenase, caused an accumulation of fructose- 1,6-bisphosphate and the triosephosphates, and a decrease in substrate-level phosphorylation with a concomitant lowering of the energy charge potential of the spermatozoa. The (R)-isomer of IX-chlorohydrin had no inhibitory activity on fructolysis.

Inhibition of glyceraldehyde 3-phosphate dehydrogenase in boar spermatozoa by bromohydroxypropanone

1995 ◽  
Vol 7 (1) ◽  
pp. 107 ◽  
Author(s):  
LM Porter ◽  
AR Jones
Keyword(s):  
Carbonyl Compound ◽  
Energy Charge ◽  
Mature Sperm ◽  
Dihydroxyacetone Phosphate ◽  
Epididymal Sperm ◽  
Charge Potential ◽  
Fructose 1,6 Bisphosphate ◽  
Boar Spermatozoa

In the presence of 3-bromo-1-hydroxypropanone (BOP), cauda epididymal sperm obtained from mature boars produced a carbonyl compound which is assumed to be (S)-3-bromolactaldehyde. Glyceraldehyde 3-phosphate dehydrogenase was rapidly inhibited which resulted in the accumulation of dihydroxyacetone phosphate and fructose-1,6-bisphosphate, and no accumulation of lactate when fructose was the substrate. The energy charge potential of the cells declined in the presence of BOP when either fructose or glycerol were substrates. It is suggested that BOP is transformed into (S)-3-bromolactaldehyde, which is the actual inhibitor of glyceraldehyde 3-phosphate dehydrogenase, thus demonstrating BOP to be the first brominated chemical to have an anti-glycolytic action on mature sperm in vitro.

Role of ATP-sensitive K+ channels in ischemic preconditioning of skeletal muscle against infarction

1997 ◽  
Vol 273 (1) ◽  
pp. H44-H51 ◽  
Author(s):  
C. Y. Pang ◽  
P. Neligan ◽  
H. Xu ◽  
W. He ◽  
A. Zhong ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion ◽  
Energy Charge ◽  
Katp Channels ◽  
High Energy ◽  
Intraarterial Infusion ◽  
Muscle Flaps ◽  
Charge Potential

We studied the role and mechanism of ATP-sensitive K+ (KATP) channels in ischemic preconditioning (IPC) of skeletal muscle against infarction in vivo. Surgically denervated, noncontractile latissimus dorsi muscle flaps in pentobarbitone-anesthetized pigs were assigned to nine groups: control; IPC (3 cycles of 10-min ischemia/reperfusion); preischemic lemakalim (LMK, 0.18 mg/muscle); postischemic LMK; sodium 5-hydroxydecanoate (5-HD, 27 mg/muscle) before IPC; glibenclamide (Glib 0.3 mg/kg iv) before IPC; 5-HD before preischemic LMK; 5-HD before ischemia; and Glib before ischemia. Except for Glib, all drugs were delivered to each muscle by 10-min local intraarterial infusion to avoid systemic effects. All muscle flaps underwent 4 h of global ischemia. Infarction was assessed at 48 h of reperfusion. In a separate study, muscle biopsies were taken before, during, and after ischemia for assay of high-energy phosphate and lactate contents and myeloperoxidase (MPO) activity. It was observed that muscle infarction in the IPC (24 +/- 2%) and preischemic LMK (21 +/- 2%) groups were smaller (P < 0.05) than that in the control (42 +/- 2%). The anti-infarction effect of IPC and LMK was blocked by 5-HD or Glib. IPC and preischemic LMK caused a higher (P < 0.05) muscle content of ATP and energy charge potential, a lower (P < 0.05) muscle content of lactate during ischemia, and a lower (P < 0.05) muscle MPO activity throughout 16 h of reperfusion compared with the control. These observations indicated for the first time that KATP channels are also involved in the anti-infarction effect of IPC in noncontractile skeletal muscle in vivo. Presently, the cause and importance of energy-sparing and neutrophil-inhibitory effects of IPC and LMK are not known.

Glycolytic enzyme activity in hypotonically treated boar spermatozoa

1999 ◽  
Vol 11 (8) ◽  
pp. 409 ◽  
Author(s):  
A. R. Jones ◽  
F. Piccolo
Keyword(s):  
Enzyme Activity ◽  
Lactate Dehydrogenase ◽  
Phosphate Buffer ◽  
Cytoplasmic Membrane ◽  
Glycolytic Enzyme ◽  
The Other ◽  
Simple Preparation ◽  
Chemical Inhibitors ◽  
Boar Spermatozoa ◽  
Phosphate Buffered Saline

Treatment of washed boar sperm with hypotonic phosphate buffer disrupted the cytoplasmic membrane and released the soluble contents and phosphofructokinase, but the other glycolytic enzymes and lactate dehydrogenase were retained. Addition of the appropriate substrates and co-factor(s) to preparations of treated cells in phosphate-buffered saline showed that enzyme activity could be re-instated. This simple preparation should be of assistance in the investigation of specific sections of the glycolytic pathway without the use of chemical inhibitors.

Total lactate dehydrogenase and its isoenzymes in serum in the presence of penicillamine and other sulfhydryl compounds.

1977 ◽  
Vol 23 (2) ◽  
pp. 229-233 ◽  
Author(s):  
L L Gershbein ◽  
K G Raikoff
Keyword(s):  
Lactate Dehydrogenase ◽  
Disc Electrophoresis ◽  
The Other ◽  
Rat Serum ◽  
Initial Concentration ◽  
Ldh Isoenzymes ◽  
Allosteric Effectors ◽  
Sulfhydryl Compounds

Abstract Toward delineation of changes in total lactate dehydrogenase (LDH) and in the distribution of LDH isoenzymes as assessed by polyacrylamide disc electrophoresis, we inbucated human and rat sera with various agents, notably sulfhydryl compounds. Although artefacts were apparent when these agents were used without preliminary adjustment of pH, we saw little alteration in total unitage when one or two volumes of serum was mixed with one volume of any of several thiols, especially penicillamine, at an initial concentration of 0.4 mol/liter and pH 7.0-7.5. Under these conditions, penicillamine caused a loss in LDH-5 after incubation for 1 h at 25 degrees C together with small decreases in mobility of the other four isoenzymes toward the anode. A zymosan region appeared below the albumin and tracking dye area. With longer periods of incubation of rat serum with penicillamine or alpha-mercaptosuccinate, a novel band in the zymogram was noted just above the LDH-4 peak. The observations are discussed in terms of allosteric effectors.

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