title: Release of dopamine, noradrenaline and dopamine B-hydroxylase from mouse neuroblastoma.
abstract: The murine C1300 neuroblastoma tumor was found to secrete dopamine, noradrenaline and dopamine B-hydroxylase into the circulation of tumor-bearing A/J mice. The plasma levels of dopamine, noradrenaline and dopamine B-hydroxylase increased with the size of the tumor, and the increase in noradrenaline paralleled the increase in dopamine B-hydroxylase (r = 0.86). The vesicular storage of dopamine and noradrenaline in the tumor was evidenced by a decrease of the tissue content of dopamine and noradrenaline 24 hours after the administration of reserpine (5 micrograms/g) respectively to 17.6% and 7.8% of control values. A similar observation could be made for the levels of dopamine and noradrenaline in the plasma of reserpinized C1300 mice. The total activity of dopamine B-hydroxylase in the tumor and in plasma was unaffected by the reserpine treatment. Chronic administration of 6-hydroxydopamine (100 micrograms/g for 8 days) had no effect on the tissue contents of dopamine, noradrenaline or dopamine B-hydroxylase. The release of catecholamines and dopamine B-hydroxylase from the C1300 neuroblastoma was studied in vitro on superfused tumor slices. Stimulation of these slices with 56 mM KC1 or with 5.10(-5) M tyramine failed to induce the release of endogenous dopamine, noradrenaline or dopamine B-hydroxylase above the basal outflow levels. These results are suggestive for a non-exocytotic release of catecholamines and dopamine B-hydroxylase from the neuroblastoma tumor.
mesh_terms: D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism*; D006892:Hydroxydopamines / Q000494:pharmacology; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D009447:Neuroblastoma / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D016627:Oxidopamine; D011189:Potassium Chloride / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology; D013997:Time Factors
chemical_list: D006892:Hydroxydopamines; D011189:Potassium Chloride; D012110:Reserpine; D016627:Oxidopamine; D004299:Dopamine beta-Hydroxylase; D004298:Dopamine; D009638:Norepinephrine