6533b7d0fe1ef96bd125a15f

RESEARCH PRODUCT

Nucleoside uptake in male germ cells of the polychaeteNereis virens

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Summary Uptake of inosine and guanosine was measured in male germ ceils of the polychaete Nereis virens at different stages of development. In spermatogonia I (spg I) and spermatid stages, total inosine uptake at 12°C and ambient concentrations of 100 μmol/1 was relatively low (10–50 nmol·ml of packed cell volume pcv−l·h−1). A rapid increase (150–300 nmol·ml of pcv-1·h−1) was found during transition from spg I to spg II with a subsequent decline to low values (10–30 nmol·ml of pcv−1·h−1) in spermatocyte and spermatid stages. This transient increase may be related to the proliferative activity of spg I stages leading to spg II stages, which increases the demand of purine precursors for nucleic acid synthesis. Inosine uptake of spermatozoa stages was extremely variable, and high uptake rates (10–300 nmol·ml of pcv−1·h−1) were found in some, but not in all, cases. In all stages the uptake rates for guanosine remained at a lower level (below 75 nmol·ml of pcv−1·h−1), and no clear stage specific pattern was ev...