A study of lactate dehydrogenase isozymes in rat ova

On the localization of lactate dehydrogenase in the ovaries and reproductive tracts of rats and mice

The localization of lactate dehydrogenase in the ovaries and reproductive tracts of rats and mice has been studied by a methodology which minimizes loss of this soluble enzyme by diffusion, and allows comment on the subunit composition of the cellular enzyme. The results differ significantly from previous data with conventional methodologies. In particular, the major localization of activity in the present study was identified in interstitial cells, and not the corpora lutea or granulosa cells; and it was noticeable that neither species exhibited massively greater expression of lactate dehydrogenase activity in the oocytes than in adjacent cell types of the reproductive tract. The goblet cells of the Fallopian tube stained intensively for activity of this enzyme. These results have been discussed in relation to the discordant data in the literature, the important role of lactate dehydrogenase in mammalian development, and the evidence for a masking of the activity of this enzyme in oocytes and pre-implantation ova.

The ontogenic characteristics of lactate dehydrogenase isozymes in mammaliam pre-implantation ova

The onotgenic characteristics of lactate dehydrogenase (LDH) isozymes in mammalian pre-implantation ova have been reviewed. Evidence has been provided that the ova of mice and other mammalian species contain enzyme activity in a masked form, and display turnover processes which possess distinctive characteristics by comparison with those in adult tissues. Also, the extraordinary high levels of LDH in the extracellular secretion of the mammaliam oviduct have been commented on, along with the influence of reproductive hormones on the activity and type of this enzyme. In addition, attention has been drawn to the unique characteristics of the oval micro-evironment, and the influence which such factors may exert on the realization of enzyme phenotype during early mammalian development.

Expression of lactate dehydrogenase isozyme 5 (LDH-5) in cultured mouse blastocysts in the absence of implantation and outgrowth

Extensive extraction studies with Triton X-100 revealed only LDH-1 (B4) but no trace of LDH-5 (A4) in one-cell and two-cell mouse and rat embryos. The LDH isozyme pattern of preimplantation mouse embryos changes from the maternally inherited B subunit isozyme (LDH-1) to a pattern dominated by LDH-5 when mouse blastocysts are cultured under conditions that prevent hatching but allow trophoblast giant cell transformation. During differentiation of mouse blastocysts in vitro, implantation is therefore not essential for the appearance of the A subunit form of LDH (LDH-5) coded for by the embryonic genome. Mechanisms controlling the expression of LDH-5 in mouse blastocysts during in vivo development are discussed.

Genetic control of quantitative variation in carbonic anhydrase isozymes of mammals. I. The concentration within single erythrocytes of the mouse

The levels of the carbonic anhydrase isozymes (CA and CA II) in single erythrocytes of DBA/2J mice were assayed by measuring the specific immunofluorescence of CA I and CA II with a microspectrofluorometric technique. Measurements of 100 randomly selected cells showed a range (in relative fluorescence units) of 21-52 (mean 31.3 +/- 7.5) for CA I and 30-80 (mean 45.6 +/- 10.7) for CA II. The CA II/CA I ratio of the means obtained by the single-cell fluorescence assay was similar to the ratios obtained for the two isozymes from hemolysates of DBA/2J mice using an immunodiffusion assay. The influence of cell age on the variation in carbonic anhydrase levels was determined by separating red cells into several fractions by a gravity sedimentation procedure. The younger cells showed higher levels of CA I and CA II than the older cells; however, the extensive overlap in the variability between the cells from the different fractions indicated that although cell age was contributing to the overall heterogeneity, its influence was not pronounced.