[Action of the extract from the optic tentacles of juvenile and adult snails on the in vivo development of the albumin gland of Helix aspersa].

Injected optic tentacle homogenates in Helix aspersa were shown to cause a decrease in growth rate and albumen gland development. The effects of optic tentacles removed from young animals and from adult animals were compared. In young animals, injections of adult optic tentacle homogenate resulted in a reduction in both growth rate and albumen gland weight. In older adult animals injected with adult optic tentacle homogenate, growth and albumen gland development decreased, but not to the same extent as in young animals. In contrast, the inhibitory effect of the young tentacle homogenate was inverted. The possible source of a tentacular factor is discussed in relation to its possible origin in other investigated pulmonates, and also the mechanism of the homogenates heterochronic action.