Effect of Analogues of Glutathione on the Feeding Reaction of Hydra

Abstract

LOOMIS¹ has shown that the ‘feeding reaction’ which Hydra littoralis exhibit after they have captured living prey is controlled chemically: the feeding reaction is elicited by glutathione released from the prey. In the absence of prey, glutathione induces writhing of the tentacles and, in higher concentrations, glutathione causes the hydra to retract the tentacles. These effects were found to be more marked when the hydra had previously been starved for several days. Loomis found that the effect was quite specific and that even the closely related aspartathione was inactive. Two analogues of glutathione (ophthalmic acid and norophthalmic acid) have recently been isolated from calf lens^2–4; they differ structurally from glutathione in that the SH group is replaced by a CH₃group in ophthalmic acid, and an H atom in norophthalmic acid. We have now found that these analogues of glutathione also elicit the feeding reactions in Hydra littoralis.