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At least 469 records · Page 26Linked to original sources
PubMed1978

Release of growth hormone in lactating and non-lactating goats in relation to behaviour, stages of sleep, electroencephalograms, environmental stimuli and levels of prolactin, insulin, glucose and free fatty acids in the circulation.

Recording electrodes were implanted in contact with the dura mater overlying the parietal cortex of six female goats, four of which were lactating. After recovery from surgery and complete familiarization with the housing conditions, the personnel and the recording technique, each goat was observed continuously for 24 h with simultaneous recording of the cortical electroencephalogram (EEG). Remote blood sampling was carried out every 30 min without disturbing the animal. Apart from the release of growth hormone (GH) associated with morning milking in two of the goats, there was no consistent relationship between the apparently spontaneous, episodic release of GH and behvaiour, stages of sleep, cortical EEG, air temperature, time of day or night, obvious environmental stimuli which arose from the normal husbandry routine, or the levels of porlactin, insulin, glucose or free fatty acids in the blood. There was also no relationship between the release of prolactin and the stages of sleep.

Animals↗
PubMed1984

Effect of changes in litter size at mid-lactation on lactation in rats.

The effect of altering the number of pups per litter from ten to two or two to ten at day 14 of lactation in rats was investigated. Reducing litter size had no effect on the daily live weight gain whereas increasing the litter size resulted in an initial weight loss followed by an impaired weight gain. Maternal food consumption decreased to values appropriate for rats feeding two pups within 2 days after litter reduction, but required at least 5 days after the increase in litter size to increase to values appropriate for rats feeding large litters from parturition. Altering the litter size resulted in maternal serum insulin concentrations that were intermediate between those expected for rats feeding two or ten pups from parturition. Maternal serum prolactin concentrations increased after litter sizes were increased and decreased initially after litter reduction before being restored to normal levels. The activities of the lipogenic enzymes, fatty acid synthase, glucose-6-phosphate dehydrogenase and 'malic' enzyme in the mammary gland all decreased within 72 h of litter reduction to levels appropriate for rats feeding two pups. Although all three enzymes increased in activity after litter size increase, only fatty acid synthase had reached values appropriate for rats feeding ten pups by 72 h.

Animals↗
PubMed1987

Enzymes of glucose and fatty acid metabolism of liver, kidney, skeletal muscle, adipose tissue and mammary gland of lactating and non-lactating sheep.

The effect of peak lactation on the activities of a number of enzymes of glucose and lipid metabolism of perirenal and subcutaneous adipose tissue, skeletal muscle, liver, kidney cortex and mammary parenchyma of sheep are described. Enzymes studied included hexokinase (glucose utilization), pyruvate carboxylase (gluconeogenesis), pyruvate dehydrogenase (glucose oxidation and production of acetyl CoA for fatty acid synthesis), acetyl CoA carboxylase (fatty acid synthesis) and glycerol-3-phosphate acyltransferase (fatty acid esterification). Major changes that were found include a decrease in activities of enzymes of fatty acid synthesis and esterification in adipose tissues, decreased activity of pyruvate dehydrogenase in muscle and adipose tissues and increased pyruvate carboxylase; there was no change in activities of enzyme of fatty acid esterification in liver. Activities of hexokinase, acetyl CoA carboxylase and glycerol-3-phosphate acyltransferase have been estimated per tissue; this shows the quantitative importance of limiting glucose utilization by muscle and of suppression of fatty acid synthesis in adipose tissue for efficient partitioning of nutrients for milk production.

Adipose Tissue↗
PubMed1992

[Study of the structure-activity features of lactate dehydrogenase isoenzymes using antipeptide antibodies to the M4-isoform of swine lactate dehydrogenase].

The structure-function peculiarities of human, porcine, rabbit, and rat lactate dehydrogenase (LDH) isoenzymes have been studied using antipeptide antibodies (AB) against the M4-isoform of porcine LDH. Antipeptide AB were raised against the hypervariable (40% homology) N-terminal fragment (residues 1-32), and the highly conservative fragment 180-214 containing histidine in the enzyme active center. Whereas antipeptide AB against the fragment of the active center of porcine LDH M4-isoform selectively inhibited the catalytic activities of LDH isoenzymes from various sources, antipeptide AB directed against the N-end were without effect. The ability of antipeptide AB to specifically interact with various isoforms of LDH suggests that sequences 1-32 and 180-214 are immunochemically identical only in the case of human and porcine M4 isoenzymes; the relatedness of the amino acid sequence to the common antigenic determinant required the absence in the given sequence of essential amino acid substituents. Chemical modification of porcine M4-isoform by diethylpyrocarbonate and the use of specific AB revealed that histidine-195 located in the active center of LDH is not directly involved in the binding to AB.

Amino Acid Sequence↗
PubMedDate not supplied

[Antigenic properties of lactate dehydrogenase isoenzymes of various biological types using antipeptide antibodies to a fragment of the active center of swine lactate dehydrogenase-M4].

Antigenic properties of human, pig, rabbit and rat lactate dehydrogenase (LDH) M4-isozyme as well as of human LDH-C4 were studied using antipeptide antibodies against pig LDH-M4 fragment (180-214). Amino acid sequence 180-214, containing His-195, which is involved in the active site of LDH isozymes, proved to be total antigenic determinant only for human and pig M4-isozymes. Amino acid sequence of total antigenic determinant did not allow any substitutions of essential amino acid residues. His-195, participating in substrate binding, was not involved immediately in reactions with antibodies as shown by means of chemical modification of pig M4-isozyme with diethyl pyrocarbonate and after production of antibodies against the modified isoenzyme.

Animals↗
PubMedDate not supplied

[Selective interaction of antipeptide antibodies to N-terminal site of lactate dehydrogenase-5 from swine muscle with various isoforms of human lactate dehydrogenase].

Antipeptide antibodies produced towards N-terminal site of lactate dehydrogenase-5 (LDH5) from pig muscular tissue exhibited specific reactions with N-terminal site of pig LDH5 and the whole enzyme molecule. An immunosorbent containing the antipeptide antibodies produced bound and precipitated all the LDH isoforms involving even a single M-subunit of the enzyme (LDH2, LDH5) but did not precipitate H4-isoform (LDH1) in extracts of human heart and skeletal muscle tissues and in blood serum of patients with myocardium infarction. The data obtained suggest that antipeptide antibodies against N-terminal site of pig muscular tissue LDH reacted selectively only with M-subunits of human LDH and did not interact with H4 isoform, which occurred due to dissimilarities in primary structure of N-terminal sites of M4 and H4 LDH isoenzymes.

Animals↗
PubMed1986

Use of purified lyophilized human lactate dehydrogenase isoenzymes in a study of the measurement of lactate dehydrogenase activity.

We examined the stability of human lactate dehydrogenase (EC 1.1.1.27; LD) isoenzymes 1, 2, and 3--purified to specific activities of about 200 kU/g--when lyophilized in a buffered stabilized matrix of bovine albumin. Each isoenzyme was prepared at two activity concentrations and stored at -20, 4, 20, 37, and 56 degrees C for as long as six months. LD-1 activity decayed with zero-order kinetics, LD-2 and LD-3 with first-order kinetics. The extrapolated half-lives of these preparations at -20 degrees C varied between 80 and 530 years. Stability of reconstituted samples stored at 4 degrees C was excellent for LD-1 but poor for LD-2 and LD-3. We suggest that preparations of human LD-1 be further investigated as a possible reference material.

Freeze Drying↗
PubMed1987

Contribution of whole blood L-lactate, pyruvate, D-lactate, acetoacetate, and 3-hydroxybutyrate concentrations to the plasma anion gap in horses with intestinal disorders.

Increased anion gap (AG) was due, in part, to L-lactic acidosis in 14 of 14 horses with intestinal disorders. In a few horses, increased whole blood concentrations of D-lactate made a minor contribution to the AG. However, the increase in AG was often greater than the sum of the increases in these 2 acid anions. This unexplained increase was not a result of increases in whole blood pyruvate, 3-hydroxybutyrate, or acetoacetate concentrations or serum albumin or phosphate concentrations. Identification of other anions causing increased AG could lead to better understanding, diagnosis, and treatment of metabolic imbalances in critically ill horses.

3-Hydroxybutyric Acid↗
PubMed1983

Cyclic AMP regulation of lactate dehydrogenase. Isoproterenol and N6,O2-dibutyryl cyclic amp increase the rate of transcription and change the stability of lactate dehydrogenase a subunit messenger RNA in rat C6 glioma cells.

The mechanism of isoproterenol and N6,O2-dibutyryl adenosine 3':5'-monophosphate (dibutyryl cAMP) induction of lactate dehydrogenase A subunit mRNA (mRNALDH) was investigated in the rat C6 glioma cell line. During the induction phase the concentration of nuclear mRNALDH sequences increased about 2.5-fold 4 h after the addition of isoproterenol or dibutyryl cAMP. Analysis of nuclear 32P-labeled mRNALDH sequences showed that isoproterenol or dibutyryl cAMP increased the basal rate of in vitro mRNALDH transcription about 3.6-fold within 4 h. The relative rates of in vivo mRNALDH synthesis were additionally measured by pulse-labeling of glioma cells for 15 min with [3H]uridine. The induction of mRNALDH in intact glioma cells by isoproterenol and dibutyryl cAMP was quantitatively comparable to that observed in isolated nuclei and the relative rate of [3H]uridine incorporation into mRNALDH was maximal 4 to 5 h after the initial induction stimulus. Increased synthesis of mRNALDH in vivo as well as in isolated nuclei occurred only at isoproterenol concentrations that caused elevated levels of glioma cell cAMP. Analysis of the kinetics of decay of [3H]uridine-labeled mRNALDH showed a linear rate of decay of non-induced mRNALDH with a t1/2 of 45 min. After isoproterenol stimulation mRNALDH decayed as two populations, one with a t1/2 of 50 min and the other one with a t1/2 of 2.5 h. These results indicate that both isoproterenol and dibutyrl cAMP regulate not only the rate of transcription of mRNALDH but that the stability of mRNALDH is increased during the induction phase.

Animals↗
PubMed1984

Rapid loss of lactate dehydrogenase isoenzyme activity in serum by cold-induced formation of immunoglobulin G-lactate dehydrogenase complex.

Lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum from a patient recovering from a myocardial infarction was extremely unstable when stored at 0 degree C. The activity of each LD isoenzyme except LD-1 decreased by at least 40% when serum was stored at 0 degree C for 4 h. The patient's erythrocyte LD activity had normal stability at lower temperatures, but LD from other sources, when added to the patient's serum, rapidly lost activity at 0 degree C. The patient's serum contained an immunoglobulin G that combined--at 0 degree C but not at 21 degrees C--primarily with LD isoenzymes containing one or more M subunits. Because this immunoglobulin-LD complex has no enzyme activity, we used 125I-labeled purified LD to study formation of the complex. NAD+ blocked the formation of immunoglobulin-LD complex but could not dissociate the complex and restore the LD activity.

Animals↗
PubMed1983

Accuracy of lactate dehydrogenase isoenzyme estimations by a thin-layer agarose fluorescent technique: experience with ternary and quaternary mixtures of purified human lactate dehydrogenase isoenzymes.

We have further assessed the accuracy of the thin-layer agarose fluorescent technique of Elevitch et al. [Am J Clin Pathol 46, 692 (1966)]. Previously, we used semi-purified human lactate dehydrogenase isoenzyme-1 and -5 [Clin Chem 22, 1995 (1976)] and isoenzyme-1 and -2 [Clin Chem 27, 1708 (1981)] to show that this assay accurately measures the proportions of these binary mixtures. In the present study, using ternary and quaternary mixtures of isoenzyme- 1, -2, -3, and -5, we show that the assay gives accurate estimations of all of these isoenzymes, within the errors of the techniques used. We also show that peak area (integration) is more nearly accurate, but less precise, than peak height (amplitude) measurements.

Chromatography, Thin Layer↗
PubMed1983

Does lactate dehydrogenase isoenzyme-5 contribute to the predictive power of total lactate dehydrogenase in myocardial infarction?

In 385 patients with acute myocardial infarction, lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes were determined electrophoretically 24, 48, and 72 h after admission. At those times, LD-1/LD-2 ratios exceeding 1 were recorded in 78.9, 88.8, and 92.2% of the cases, respectively. LD-1 ranged from 181 to 2674 U/L, or 21.9 to 66.1% of the total activity. On the first day of hospitalization, 27.3% of the patients demonstrated abnormal LD-5 (greater than 6% of total LD); this finding dropped to 20.5% and 17.4% in the two following days. Early increases in LD-5 were most frequently observed in patients associating inferior infarcts with posterior or lateral extension and having a previous history of myocardial infarction. On day 1, LD-5 was significantly increased in early deceased patients as compared to long-term survivors (9.7% vs 4.9% of total LD, p less than 0.01). LD-5 definitely contributes to the prognostic efficiency of total LD in acute myocardial infarction, but does not replace it as a risk predictor. This study confirms the superiority of total LD over the isoenzyme measurements to achieve short-term prognostication.

Aged↗
PubMed1983

Hypertonic sodium lactate versus lactated ringer's solution for intravenous fluid therapy in operations on the abdominal aorta.

Fifty-eight patients who were to undergo aortic reconstruction were prospectively randomized into two groups to compare the effects of perioperative fluid replacement with isotonic and hypertonic crystalloid solutions. Blood loss was replaced with packed red blood cells, and additional fluid was given as either Ringer's lactate solution (RL, 130 mEq sodium/L, 274 mOsm/L) or a hypertonic balanced salt solution (HSL, 250 mEq sodium/L, 514 mOsm/L). Fluid was administered to maintain the cardiac filling pressure within 3 torr of the preoperative level and the cardiac output (CO) at or above the preoperative level. The groups were similar with respect to age, preexisting disease, duration of operation, and operative blood loss. During the operation, the RL group required 9.5 +/- 0.8 L of fluid, whereas the HSL group required 4.5 +/- 0.3 L (P less than 0.001). Pulmonary, cardiac, and renal functions were adequately maintained in both groups. There were no significant differences between the groups with regard to CO, urine output, or creatinine clearance during the operation and early postoperative period. Postoperatively, the intrapulmonary shunt was 20 +/- 1% in the RL group and it was 16 +/- 1% in the HSL group (P less than 0.05). The amount of sodium infused and the cumulative sodium balance at the completion of the study period were similar in both groups. Serum sodium and osmolarity were significantly greater in the HSL group (P less than 0.001), reaching a maximum of 151 +/- 1 mEq/L and 305 +/- 2 mOsm/L, respectively. Two patients in the HSL group had a persistent elevation in serum osmolarity (greater than 320 mOsm/L) during operation, for which they received RL for the balance of the resuscitation. There were no complications that could be attributed to the hypertonicity of the solution. HSL is effective for resuscitation of patients with extracellular fluid deficit and is safe provided that the serum sodium and osmolarity are monitored during periods of large volume administration.

Aorta, Abdominal↗
PubMedDate not supplied

[Glucose-6-phosphate dehydrogenase and lactate dehydrogenase activities and lactate dehydrogenase isoenzyme spectrum in human myocardium after sudden death caused by acute alcohol intoxication and ischemic heart disease].

Alterations in activities of lactate- and glucose-6-phosphate dehydrogenases and in the LDHisozyme spectra in human heart muscle after sudden death, caused either by acute ethanol intoxication or by ischemic heart disease, were characterized by inhibition of aerobic oxidation and activation of the glycolytic pathway of energy formation.

Adult↗
PubMed1995

Rapid and easy procedure for the determination of immunoglobulin class and light chain type of anti-lactate dehydrogenase antibodies in macro-lactate dehydrogenase.

We developed an easy to perform and rapid method for determination of the immunoglobulin class and light chain type of anti-enzyme antibodies present in macro-enzymes. The procedure is a combination of two routinely used laboratory kits, and it allows identification of the antibody involved within 1.5 hour. The applicability of the method was demonstrated for macro-lactate dehydrogenase.

Anemia, Hemolytic↗
PubMedDate not supplied

[Formate metabolism by lactate-producing and lactate-utilizing rumen bacteria].

Physiological concentrations [< 11 mM] of formate do not violate the metabolism of S. bovis and M. elsdenii. A significant inhibition is caused by concentrations of 22 and 44 mM. In this case the process of ammonia formation in S. bovis is inhibited more pronouncedly. Peculiar effects of formate (11 mM) on LDH, FDH, aconitase, isocitrate dehydrogenase, fumarase, L-MDH and malic-enzyme have been stated. The changes show that it enhances assimilation of sugars fermented to lactate in S. bovis, in contrast to M. elsdenii, where it activates the utilization of lactic acid. During the log-phase S. bovis utilized only 11.5% of [14C] H2O2, whereas M. elsdenii uses 33.4% of it. The major amount of the label is transferred from intracellular inclusions to nucleic acids (in S. bovis--74.7%, in M. elsdenii--87%) and then incorporated into low molecular substances (23.5 and 11.9%, respectively), the rest being incorporated into proteins and lipids.

Animals↗
PubMed1994

Fast-type electrophoretic variant of lactate dehydrogenase M(A) and comparison with other missense mutations in lactate dehydrogenase M(A) and H(B) genes.

An electrophoretic variant of lactate dehydrogenase (LD) M(A) subunit was discovered in a female patient with chest pain. Her LD activity in serum was within the normal reference interval, and analysis of her LD isoenzyme pattern showed an abnormal migration indicating a fast-type LD-M(A) subunit variant. DNA analysis of the mutant LD-M gene detected a single base substitution, an A to G transition at codon 220 (AAA-->GAA). This mutation resulted in the replacement of a lysine by a glutamic acid (mutation K220E) and produced a subunit variant (electrophoretic fast type). This missense mutation was also observed in the patient's son, and genotypes of mother and son were consistent with their biochemical phenotypes, as evaluated by LD isoenzyme analysis.

Base Sequence↗