Ferritin in mantle pore cells and its role in reproduction of Helisoma duryi (mollusca: Pulmonata)

Abstract

AbstractThis study was undertaken to investigate the ferritin content of pore cells in the mantle of Helisoma duryi and the possibility of these cells being a source of vitellogenic ferritin. Ultrastructurally pore cells in the mantle resemble those previously studied in the heart/kidney region, except that their plasma membrane is less elaborate. The presence of iron is demonstrated in the cells by the Prussian blue reaction, and in the ferritinlike contents of cytoplasmic vesicles by energy dispersive X‐ray analysis. Egg‐laying activity begins 2 days after virgin snails are allowed to mate. By means of radioimmunoassay it is found that mantle (containing pore cells) ferritin content increases rapidly at the onset of egg‐laying, then declines to reproductive levels. As it declines, the blood ferritin content increases to reproductive levels. Ovotestis and digestive gland ferritin contents drop at the onset of egg‐laying, then rapidly return to reproductive levels. The relationships between the ferritin contents of these four tissues at the onset of and subsequent to egg‐laying are discussed. The ferritin contents of various tissues are determined by radioimmunoassay (RIA) after the removal of endocrine dorsal bodies from reproducing snails. The ferritin levels remain unchanged in the blood and digestive gland, increase in the mantle, and decrease in the ovotestis. A possible influence of dorsal body hormone on ferritin uptake by vitellogenic oocytes is discussed.