A putative hyperglycemic factor from the cerebral ganglia of Otala lactea (Mollusca: Pulmonata)

Abstract

Mantle tissue pieces from adult Otala lactea continuously synthesized glycogen over a 72-h incubation period. Acid-saline extract of the cerebral ganglia inhibited glycogen synthesis by mantle tissue in vitro. This effect was dose-dependent. The glycogen reduction factor from the cerebral ganglia was heat stable, protease sensitive, and relatively hydrophobic. The cerebral ganglia extract also stimulated mantle glycogen phosphorylase in vitro in a dose-dependent manner. The results suggest the presence of a hyperglycemic factor in the cerebral ganglia of Otala. The molecular weight of this factor, estimated by size-exclusion chromatography, was approximately 10,000. Mammalian glucagon had no significant effect on glycogen synthesis by the mantle pieces.

Carbohydrate metabolism in the central nervous system of the megalobulimus oblongus snail during anoxia exposure and post‐anoxia recovery

“…In Lymnaea, this hyperglycemic factor inhibits glycogen synthesis and stimulate glycogen breakdown in the mantle tissue (Hemminga et al,'85a) or on isolated glycogen cells (Hemminga et al,'85b). The hyperglycemic factor has the same effect on pieces of mantle tissue from Otala lactea (Abdraba and Saleuddin, 2000). Moreover, there is evidence for the release of the hyperglycemic factor from cerebral ganglia during anaerobiosis (Hemminga et al,'85c).…”

“…For these cells, the functional name ''glycogen cells'' has been proposed (Joosse and Geraerts,'83). In addition, a hyperglycemic factor released from cerebral ganglia has been described in the freshwater pulmonate snail Lymnaea stagnalis (Hemminga et al, '85a,b,c) and in the land pulmonate Otala lactea (Abdraba and Saleuddin, 2000). In Lymnaea, this hyperglycemic factor inhibits glycogen synthesis and stimulate glycogen breakdown in the mantle tissue (Hemminga et al,'85a) or on isolated glycogen cells (Hemminga et al,'85b).…”