A cytofluorometric and radiochemical analysis of the uptake and turnover of 5-hydroxytryptamine in mast cells.
Uptake and turnover of 5-hydroxytryptamine (5-HT) after the administration of 5-hydroxytryptophan (5-HTP) has been studied in rat peritoneal mast cells using radiochemical and quantitative cytofluorometric methods. There was a close agreement between the results obtained with the two methods. The extreme sensitivity of the cytofluorometric method was indicated by the fact that 0.2 pg 5-HT contained in mast cells from control rats could be readily quantitated. The cytofluorometric analysis demonstrated a large variation in 5-HT content of individual mast cells within the mast cell populations. The storage capacity for 5-HT greatly exceeded the amount found in normal mast cells. Intraperitoncally injected 5-HTP was rapidly taken up and eliminated from the mast cells within 12 hr, while 5-HT, probably derived from intracellular decarboxylation of 5-HTP, was retained in the cells and slowly eliminated. The elimination of 5-HT followed an exponential course and the half-life was found to be about 10 days. The results indicate that the turnover of 5-HT is much slower in mast cells than in other cells which normally store 5-HT.
D006916:5-Hydroxytryptophan / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002855:Chromatography, Thin Layer; D005069:Evaluation Studies as Topic; D008407:Mast Cells / Q000378:metabolism* / Q000648:ultrastructure; D008722:Methods; D008856:Microscopy, Fluorescence; D051381:Rats; D012701:Serotonin / Q000378:metabolism*; D013997:Time Factors; D014316:Tritium
D014316:Tritium; D012701:Serotonin; D006916:5-Hydroxytryptophan