Quarterly Journal of Microscopical Science, Vol s3-97, 499-517, Copyright © 1956 by Company of Biologists

A Histochemical Study of the Adipose Cell of the Leech, Glossiphonia Complanata

¹ Cytological Laboratory, Department of Zoology, University Museum, Oxford

The adipose cell of the leech Glossiphonia complanata has been studied both morphologically and histochemically. It is more or less globular in shape, with a diameter of from 10 µ to 40 µ; the protoplasm is clearly marked off into two zones, the ground cytoplasm around the periphery of the cell, and a denser, basiphil zone (termed the ‘surround’) which encloses the fat drops and the nucleus. Large thread-like mitochondria are scattered throughout the cell; they are especially numerous in the ‘surround’.

Histochemical tests showed that the ground cytoplasm contained arginine, tyrosine, glycogen, RNA, and inorganic iron; the ‘surround’ has, in addition to these, much phospholipid, some unsaturated lipid, and some acid mucopolysaccharide.

The large fat drops and some other smaller fat droplets found in the ground cytoplasm are chiefly composed of neutral lipid, possibly triglyceride; they also contain some cholesterol or cholesteryl esters and some unsaturated lipid. The lipochondria of the ground cytoplasm and the ‘surround’ differ from these in that although they may contain some or all of the substances found in the large fat drops, their principal constituent is phospholipid. The mitochondria also react positively to the test for phospholipid.

Some granules found in the ‘surround’ and in the ground cytoplasm were shown to contain inorganic iron. The ‘fuchsinophil’ granules of Bobin are almost certainly identical with the lipochondria.

Both the large fat drop and the glycogen are reserve food stores.