[in Japanese]

View full abstract

An assay method for hypoxanthine-guanine and adenine phosphoribosyltrans-ferase in hemolysate of human red cells and liver of mice is described.
Reaction was carried out in a microtube using isotope labelled substrate and terminated by the addition of formic acid. An aliquot of the reaction mixtures was applied on cellulose acetate membrane over standard carrier substances and the products were separated electrophoretically using two buffer systems, 0.1 M borate buffer pH 9.0 and 0.1 M Tris-HCI buffer pH 7.5. The areas corresponding to the products were identified by inspection of the strip under ultraviolet light, cut out and counted in a liquid scincillation counter. The enzyme activity was calculated from the recovery of radioactivity associated with the products.
In this assay method, the electrophoretic apparatus commonly used inclinical laboratory was used and the enzyme activities in tissue extracts which contained various enzymes concerning with purine metabolism could be assayed by electrophoresis using two buffer systems.

View full abstract

This study was designed to elucidate the relationships between the propionate metabolism and TCA cycle in mammary gland, and how the relationships were influenced by starvation and alloxan treatment. The following results were obtained in a study of the influence of citrate or succinate on the ¹⁴C-propionate metabolism and those of propionate on the metabolism of ¹⁴C-citrate or ¹⁴C-succinate in mammary gland slices of normally fed, starved and alloxan diabetic sheep.
In normal and starved condition, the ¹⁴C-propionate consumption and the transfer of ¹⁴C from IT-propionate into CO₂ and lipid increased by the addition of citrate and succinate. The consumption of ¹⁴C-citrate and ¹⁴C-succinate and the transfer of ¹⁴C from ¹⁴C-citrate and ¹⁴C-succinate into CO₂ and lipid decreased by the propionate addition. Effects of citrate and succinate on the propionate metabolism and those of propionate on the metabolism of citrate or succinate in starved condition were larger than the cases of normal condition. Effects of citrate on the propionate metabolism and those of propionate on the citrate metabolism disappeared following treatment of alloxan. But the effects of succinate on the propionate metabolism were observed in alloxan diabetes, and the effects of succinateon the propionate metabolism and those of propionate on the succinate metabolism were larger than the case of normal and starved condition.
As mentioned above, there were some relationships between the propionate metabolism and TCA cycle, and these relationships changed due to starvation and alloxan treatment.(Supported by NIH grant HD 02375)

View full abstract

A Simplified radioimmunoassay for the measurement of serum pregnenolone is described. Antibodies against pregnenolone were generated in rabbits immunized with pregnenolone 3-bovine serum alubmin conjugate. Since antibodidies having high specificity and sensitivity were obtained, pregnenolone was estimated by the radioimmunoassay after only extraction with hexane without further purification. The sensitivity varied between 0.08 and 0.2ng of pregnenolone. Recovery experiments of pregnenolone added to serum and water confirmed accuracy. Normal serum concentrations of serum pregnenolone determined by this method were; men (1.20±0.20ng/ml); women, follicular phase (1.27±0.15ng/ml) luteal phase (1.42±0.25ng/ml). These mean values were not significantly different from those reported by other workers. The coefficient of variation with in an assay was 8% and it was 16% between assays.

View full abstract

Correction of temperature coefficient for lactate dehydrogenase (LDH) activity in human serum was studied.
In the case of healthy serum, it was identical with the value reported by Henry et al4). However, the value of coefficient factor was markdly different when serum with high LDH activity was employed. Moreover, when sera from patients with myocardial infarction and hepatitis were assayed, two values of coefficient factor were affected remarkably significant by temperature variation.
According to an Arrhenius plot, it showed two phases, namely the straight line based on activity was sharpened steeply and sharpened gently later as the temperature rose. The break occurs around 40°C, where the enzyme molecule appears to start to unravel slowly.
From the facts described above, it was consumed that enzyme might be denatured at considerably lower temperature than that reported by others and, it was moreexactly value that the coefficient factor was obtained at the temperature from 25°C to 40°C.

View full abstract