Intraventricular administration of nanogram quantities of nerve growth factor to adult rats results in a marked increase in the activity of ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) in the brain. The increase occurs in all major brain regions and the activity is maximal by 7.5 hr after administration. The enzyme response to nerve growth factor increases in magnitude durin...

A transient increase in ornithine decarboxylase activity and polyamine biosynthesis occurs in the intestinal mucosa of the newborn rat in the third week after birth. During this period, there is a rapid conversion of the mucosa from a fetal to a mature adult status. A similar increase in ornithine decarboxylase activity also accompanies the rapid recovery of the mucosa 1 week after an injury is...

The control of polyamine synthesis in neoplastic cells is complex and incompletely understood. Using murine lymphoma cells deficient in methylthioadenosine (MTA) phosphorylase, we have analyzed the role of MTA in the regulation of ornithine decarboxylase and S-adenosylmethionine (SAM) decarboxylase, the two rate-limiting enzymes in the polyamine-biosynthetic pathway. The addition of MTA to the ...

Starvation of the polyamine-dependent Chinese-hamster ovary cells for ornithine or ornithine-derived polyamines in serum-free culture resulted in the formation of cadaverine and its aminopropyl derivatives, N-(3-aminopropyl)cadaverine and NN'-bis(3-aminopropyl)cadaverine. The synthesis of these unusual amines was inhibited by treatment of the cells with DL-2-difluoromethylornithine, a specific ...

The effect of Phaseolus vulgaris isolectin E4 on polyamine concentrations and ornithine decarboxylase activity of proliferating and differentiating Caco-2 cells was investigated. Values of putrescine, spermidine, and spermine in control cells were highest during the early phase of proliferative cell growth and lowest in the stationary phase. Phytohaemagglutinin E4 significantly increased cellul...

In extracts from the youngest leaves of Avena sativa, Hordeum vulgare, Zea Mays, Pisum sativum, Phaseolus vulgaris, Lactuca sativa, and four pyrrolizidine alkaloid-bearing species of Heliotropium, the activities of ornithine decarboxylase, close to V(max), ranged between traces and 1.5 nanomoles per hour per gram fresh weight when based on putrescine formed during incubation with labeled ornith...

1. Ornithine decarboxylase activity is stimulated in high-density HeLa-cell cultures by dilution of or replacement of spent culture medium with fresh medium containing 10% (v/v) horse serum. 2. After stimulation, ornithine decarboxylase activity reaches a peak at 4-6h, then rapidly declines to the low enzyme activity characteristic of quiescent cultures, where it remains during the remainder of...

Resection of the colon in patients with familial adenomatous polyposis frequently results in the regression of polyps in the remaining rectum, suggesting a reduction of cellular proliferation. These patients remain at risk of developing rectal cancer but whether this risk increases with time is uncertain. Since ornithine decarboxylase activity is associated with cellular proliferation, mucosal ...

Topical application of retinole acid to mouse skin led to a dramatic inhibition of phorbol ester (12-O-tetradecanoylphorbol-13-acetate)-induced epidermal ornithine decarboxylase (EC 4.1.1.17) activity, an event proposed to be essen tial for tumor promotion. The degree of inhibition was de pendent on the dose and time of application of retinoic acid. In contrast, treatment with retinoic acid did...

Induction of ornithine decarboxylase has been correlated with the onset of cellular proliferation and cAMP production. Whether the resulting increases in polyamine levels are essential mediators of growth and/or differentiation or are merely incidental remains controversial. We have used FRTL-5 thyroid cells in culture to study the effects of three growth factors on ornithine decarboxylase acti...