Isozyme patterns of lactate dehydrogenase, creatine phosphokinase, phosphoglucomutase and aldolase guinea pig tissues during ontogeny

Evolutionary implications of lactate dehydrogenases (LDHs) of hagfishes compared to lampreys: LDH cDNA sequences from Eptatretus burgeri, Paramyxine atami and Eptatretus okinoseanus

Heart muscles of hagfishes Paramyxine atami and Eptatretus okinoseanus express the B4 isozyme of lactate dehydrogenase [L-LDH: NAD oxidoreductase, EC 1.1.1.27] (LDH-B4) whereas their skeletal muscles express LDH-A4. To examine the relationship of hagfish LDHs to lamprey and other vertebrate LDHs, we determined the cDNA sequences of LDH-A from three hagfishes and compared them with previously published sequences. A phylogenic tree shows that hagfishes diverged just after lampreys. The deduced amino acid sequences showed ten regions common to all vertebrate LDHs examined, i.e., the active site, the pocket recognizing the substrate-coenzyme complex, part of a loop at the surface, and the substrate binding site. The cyclostomate-specific regions (S1, S2) were located in the neighborhood of the active site loop. Three regions, IGS1, IGS2 and IGS3, seem to have altered their structures during the differentiation of LDH isozymes, and the regions remain in LDH-B of vertebrates hitherto examined. IGS2 and IGS3, which are in the neighborhood of the active site, may regulate catalytic activity. There were differences in six amino acid residues (6, 10, 20, 156, 269, and 341) in LDHs of hagfishes. These differences might reflect the tolerance to high pressure and low temperature of LDHs from hagfishes at different habitat depths.

Assessment of immunocytochemical techniques with particular reference to the mixed-aggregation immunocytochemical technique

Antibody-mediated assays are believed to be the most sensitive and specific techniques for antigen localization available to date, but they need extensive controls if specific and quantitative results are to be obtained. Problems arise from both the antibody source and the antigen in the tissue preparation. Specificity of the antibody is often difficult to prove in any direct or indirect antibody technique. When markers are coupled to antibody, binding and diffusion properties of the antibody are changed. Diffusion of antigen from its site and loss of antigenic determinants due to procedures for preserving morphology are two other main problems. The mixed-aggregation immunocytochemical technique provides another way of checking the selectivity of the antibody, since a cross-reactive antigen introduced into the section and not the antibody itself is what is seen. Quantitative studies using localization of lactic dehydrogenase isoenzymes in human skeletal muscle fibres show that the technique fulfils most of the present criteria on precision, specificity and validity for determination of enzymes. It also ensures that more than 80% native antigen in frozen sections is fixed and is two to three times more sensitive and selective than the direct antibody technique.

Localization of lactate dehydrogenase isozymes in human muscle tissues by the mixed aggregation immunocytochemical technique

Lactate dehydrogenase (LDH) isozyme composition and localization was determined in sections of skeletal, heart and smooth muscle by the mixed aggregation immunocytochemical method using first antibody directed against purified human LDH-A4 (M4) or LDH-B4 (H4) followed by the enzymes LDH-A4 and LDH-B4, respectively. An even distribution of the two monomers in all fibres was seen with heart muscle and smooth muscle. Heart muscle had a low concentration of A-monomers and a high concentration of B-monomers, whereas the smooth muscle had equal concentrations of the two monomers. In contrast, skeletal muscle from m. quadriceps femoris was found to be composed of two muscle fibre types, one containing mainly A-, the other mainly B-monomers. On the basis of succinate dehydrogenase activity it was shown that the red (type 1) fibres contain mainly B-monomers and the white (type 2) fibres mainly A-monomers of LDH.

Creatine phosphokinase activity in dysgenic (mdg/mdg) mouse muscle

The specific activity of creatine phosphokinase (CPK) was measured in the muscle of mdg/mdg and control embryos of 14-18 days' gestation. CPK specific activity values were similar in mutant and normal embryos at the earliest stages examined (14-15 days). However, after 15 1/2 days, the specific activity of the enzyme in the mdg/mdg embryos was approximately 50% lower than in the controls. The dysgenic and normal muscle extracts exhibited comparable stability after storage at -85 C. CPK activity levels in the muscle of adult heterozygotes (+/mdg) and wild-type (+/+) controls were found to be statistically identical. The findings suggest that the mdg mutation does not have a primary or direct effect on CPK activity.

Differentiation of epithelial cells in human jejunum: localization and quantification of aminopeptidase, alkaline phosphatase and aldolase isozymes in tissue sections

Sections from human jejunum were stained histochemically for aminopeptidase and alkaline phosphatase and the aldolase isozymes were detected with the mixed aggregation immuno-cytochemical technique. All enzyme concentrations increased from the bottom to the upper part of the crypt. The concentration of aldolase-A per cell was the same in the upper part of the crypt and the villus, whereas the concentration of the other three enzymes was still higher. Therefore, high amounts of aldolase-B, aminopeptidase and alkaline phosphatase are present in cells highly active in absorption in a fashion similar to that found in the proximal tubule cells of kidney. The relatively undifferentiated cells of the crypts contained both aldolase-A and aldolase-B. Alkaline phosphatase gains its full activity later than aminopeptidase. The synthesis of microvillar membrane enzymes comes to an end earlier than that of the cytosol enzymes.

The differentiation of proximal and distal tubules in the male rat kidney: the appearance of aldolase isozymes, aminopeptidase and alkaline phosphatase during ontogeny

1. The specific activities of aminopeptidase, alkaline phosphatase and aldolase isozymes were measured in homogenates of kidneys taken at different stages of ontogeny. The cellular localization of these enzymes was studied in cryostat tissue sections using substrate linked assays for aminopeptidase and alkaline phosphatase and the mixed aggregation immuno-cytochemical technique for aldolase isozymes; local enzyme concentrations were estimated photometrically. 2. The presence of both aldolase-A and aldolase-B was demonstrated in all metanephrogenic cells (and at still higher concentrations in collecting tubule cells) of the rat fetus 16 days after conception and in the undifferentiated cells of the neogenetic zone of kidney up to 8 days after birth; no aminopeptidase or alkaline phosphatase could be found in these cells. 3. Measurements made on stained tissue sections show that the shift towards aldolase-B, seen in homogenate analyses, is due to a change in the relative amounts of proximal tubules. No evidence was seen for repression in the synthesis of aldolase-A or aldolase-B monomers in the different kidney cells during ontogeny. 4. Two transitions in the mode of nephron differentiation were observed: one was shortly after birth, the other followed weaning. Before the first transition the concentrations of the enzymes increased to different degrees, such that the enzymes reached concentrations comparable with those as in the cells of adult rats by 2 to 4 days post partum. After the second transition proximal tubule size and specific activity of brush border membrane enzymes increased 3 fold. In contrast, the distal tubules did not increase significantly in size, but their aldolase-A concentration increased 3 fold. 5. Evidence based on enzyme quantification and morphometry in kidney sections is presented to demonstrate that the proximal tubule cells show functional adaptation by two independent mechanisms: specific amplification of gene expression and hypertrophy. In contrast, the distal tubule shows functional adaptation only by specific amplification of gene expression.

Histological examination of the aldolase monomer composition of cells from human kidney and hypernephroid carcinoma

Aldolase was specifically fixed in tissue sections by the use of antibody prepared either against aldolase A or against aldolase B. The localization of the antigen was demonstrated with the immuno-histochemical method. Aldolase A was found to be the predominant constituent in the cytoplasm of the distal tubules, the large vessels and the glomerula of normal kidney, and aldolase B in the proximal tubules. The collecting tubules and the capillaries contained a mixture of the two types. In the hypernephroid carcinoma cells only aldolase A could be found, but the capillaries within the tumor tissue did contain some aldolase B. Confirmation of these results was obtained by analysis of homogenate prepared with carefully selected tissue parts.

The cellular distribution of aldolase isozymes in rat kidney and brain determined in tissue sections by the immuno-histochemical method

The use of the immuno-histochemical method permits the localization of aldolase isozymes in tissue sections. Upon incubating a section with a monomer-specific antiserum, isozymes containing that monomer remain in the section, whereas other cytoplasmic enzymes diffuse out of the section. If soluble antigen is added subsequently, it is bound by the tissue-bound antibody. These antibody fixed aldolases can then be stained by the use of a tetrazolium test linked to substrate hydrolysis. In this way it was demonstrated that isozymes of aldolase containing mostly the A monomer are predominantly localized in the distal tubules, the collecting tubules, the vessels and capillaries of the kidney, the ganglia, the Purkinje cells, the neurons, the white matter and the chorioid plexus of the brain. Aldolase containing mostly B-monomers were found in the proximal tubules. Aldolase isozymes particularly rich in C-monomers were seen in the nervus opticus, the pia mater, the vessels of cerebrum and the molecular layer of the cortex cerebelli.

Specific changes in the messenger ribonucleic acid content of the rat ventral prostate gland after androgenic stimulation. Evidence from the synthesis of aldolase messenger ribonucleic acid

1. Aldolase was selected as a suitable marker for following the androgenic regulation of mRNA synthesis in the prostate gland. 2. Antibodies raised in rabbits against crystalline prostate aldolase were used to monitor the synthesis of this androgen-induced enzyme after hormonal stimulation of castrated animals, by using procedures in vivo and in vitro for the translation of prostate poly(A)-rich mRNA. 3. After androgenic stimulation in vivo the poly(A)-rich mRNA was isolated from the prostate gland and other tissues of castrated rats, and added to a protein-synthesizing system in vitro derived from Krebs II ascites-tumour cells. By using this approach it was found that androgens regulate the synthesis of aldolase mRNA in a highly tissue-specific manner. Stimulation of aldolase mRNA synthesis reached a maximum after 8h of androgenic treatment and then declined. 4. The androgenic control of aldolase mRNA synthesis was also investigated in vivo. After treatment of castrated animals with various steroids in vivo [(35)S]methionine was injected directly into the prostate gland, and labelled aldolase was selectively precipitated from isolated polyribosomes with anti-aldolase serum. The regulation of aldolase mRNA synthesis in the prostate gland was stringently steroid-specific and could only be evoked by androgens. After a single injection of testosterone, aldolase synthesis reached a maximum after 16h of hormonal stimulation and then declined. 5. Although androgens exert significant control over transcriptional processes in the prostate gland, and appear to regulate the synthesis of aldolase mRNA de novo, the possibility exists for additional means of control at the translational level of aldolase synthesis. The results are discussed in the context of the overall mechanism of action of androgens.