Polyamines and cell proliferation in the sea star Pycnopodia helianthoides

1. Diamines (putrescine and cadaverine) and polyamines (spermidine and spermine) were extracted from tissues of the sea star Pycnopodia helianthoides, separated and quantitated using reversed-phase high-performance liquid chromatography (RP-HPLC). Simultaneous measurements of levels of protein and DNA and rates of incorporation of 14C-thymidine were carried out. 2. The most abundant polyamine in tissues was spermidine (0.3873-2.5282 nmol/mg tissue) followed by spermine (0.103-1.5517 nmol/mg tissue), putrescine (0.2096-0.5322 nmol/mg tissue) and cadaverine (0.022-0.6064 nmol/mg tissue). 3. An unknown molecule with derivatization and elution behaviour similar to that of polyamine standards was detected in all tissues. 4. Protein levels ranged from 20.47 mg/g tissue in the body wall to 48.44 mg/g tissue in the pyloric caecum. 5. DNA levels were lowest in the ovary (0.25 mg/g tissue) and highest in the testis (5.62 mg/g tissue). 6. Incorporation of 14C-thymidine was highest in the testis. Testicular tissue had the highest spermidine/spermine ratio (5.4). A significant correlation between the spermidine/spermine ratio and 14C-thymidine incorporation (expressed either as DPM/g tissue or DPM/mg protein) suggests that polyamines are implicated in the regulation of cell proliferation in the sea star P. helianthoides.