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.
