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Biomedical subjects

D H Russell

Publications and source records attributed to D H Russell.

At least 235 records · Page 13Linked to original sources
PubMed1973

Stimulation of ornithine decarboxylase activity and inhibition of S-adenosyl-L-methionine decarboxylase activity in leukaemic mice by methylglyoxal bis(guanylhydrazone).

Administration of methylglyoxal bis(guanylhydrazone) to leukaemic mice results in an early depression followed by a marked elevation of S-adenosyl-l-methionine decarboxylase activity. Further, there is an early prolonged increase in the activity of ornithine decarboxylase, the initial enzyme in the polyamine biosynthetic pathway. Because of the profound effects of methylglyoxal bis(guanylhydrazone) in vivo on the polyamine biosynthetic pathway, the drug can no longer be considered a specific inhibitor of spermidine synthesis.

Adenosine↗
PubMed1972

Spermine synthesis in the uterus of the ovariectomized rat in response to oestradiol-17 .

We reported that spermidine and spermine pools in the uterus both doubled within 24h after oestradiol administration to castrated rats (Russell & Taylor, 1971). Now we have studied the enzymic synthesis of spermine (by spermidine-dependent S-adenosyl-l-methionine decarboxylase) and find that the activity of the enzyme(s) involved is elevated soon after hormone administration. Enzyme activity is increased within 4h and is five times that of controls within 24h. Cycloheximide or actinomycin D administered at the time of oestradiol injection completely blocked the increase in enzyme activity. The enzyme involved in spermine synthesis, S-adenosyl-l-methionine decarboxylase, with S-adenosyl-l-methionine and spermidine as required substrates, was partially purified on Sephadex and DEAE-cellulose columns. The decarboxylation of S-adenosyl-l-methionine could not be separated from the transfer of a propylamine moiety from the decarboxylated S-adenosyl-l-methionine to spermidine to form spermine. We were unable also to separate this system from the enzyme that formed spermidine when S-adenosyl-l-methionine and putrescine are used as substrates. Spermidine-stimulated S-adenosyl-l-methionine decarboxylase has an apparent half-life of 60min, identical with the half-life reported for putrescine-stimulated S-adenosyl-l-methionine decarboxylase. These results strongly suggest that the same enzyme(s) operate in the synthesis of both spermidine and spermine.

Animals↗