Cellular and subcellular localization of polyamines cytochemical methods providing new clues to polyamine function in...

Studies on the cellular and subcellular localization of polyamines have previously been hampered by the rapid redistribution of these organic cations during cell fractionation. Cytochemical methods selectively localizing polyamines would, hence, be important for our understanding of where polyamines are stored and where they work. With the aid of chemical characterizations of tissue extracts, biosynthesis experiments and cytochemical model experiments we show that the cytochemical formaldehyde-fluorescamine (FF) technique selectively detects the polyamines spermine and spermidine. Results obtained with the FF method concur with previous chemical observations by showing that growing and neoplastic cell populations are rich in cytochemically detectable polyamines. The FF method also localizes polyamines to certain normal secretory cell systems, including pancreatic exocrine and endocrine (insulin) cells, cells and secretion products in the ventral prostate, pituitary growth hormone cells and neurosecretory nerve endings and leucocytes. In most cell systems studied, polyamines appear to be most concentrated in cytoplasmic structures. However, in HeLa cell mitotic chromosomes and in frog red cell nuclei most polyamines seem to be chromosomes and in frog red cell nuclei most polyamines seem to be associated with chromatin. These observations raise important questions concerning both extra- and intracellular functions of polyamines.