Regulation of galactogen synthesis in the slug Ariolimax columbianus

Abstract

1. 1. Galactogen content of the albumin gland of the slug Ariolimax columbianus shows seasonal variation. It is highest during the breeding season and lowest during the period following egg-laying. 2. 2. Removal of optic tentacles is followed within 3 weeks by an increase in the weight of the albumin gland. 3. 3. This is accompanied by an increase in galactogen concentration of the albumin gland. Both effects are reversed by injection of an extract of optic tentacles. 4. 4. Glucose 14C injected into slugs is incorporated into galactogen. The incorporation is greater following removal of optic tentacles than in normal animals. This effect is also reversed in the experimental animals by the injection of optic tentacle extract. 5. 5. In vitro experiments on galactogen synthesis do not show any significant influence of the optic tentacle extract on galactogen synthesis. 6. 6. The present evidence suggests that growth of the albumin gland is under endocrine control from a center in the optic tentacle, and that endocrine effects on synthesis of galactogen are a consequence of the effect on growth.