Glutathione (GSH)-Induced Bud Initiation in Hydra oligactis

Budding in the genus Hydra was first described in the scientific literature, and sketched, by Leeuwenhoek (1). Since that time, budding has continued to be a popular problem for developmental biologists who study Hydra (2, 3, 4). The relationship between ,feeding and budding was established in mass culture experiments performed by a number of investigators (5, 6, 7, 8, 9). The discovery by Schaller (10) of a low-molecular-weight peptide released by the nerve cells of Hydra in response to feeding or injury, and her determination that this polypeptide acts as a mitogen (1l), taken together with studies showing a correlation between the mitotic index and the budding rate in Hydra (7, 12, 13) left little doubt that feeding and budding are causally related. Recent studies continue to reinforce the observation that reduced glutathione (GSH), or glutathione derivatives, can elicit the feeding response in Hydra (14, 15). But the literature is mute about the possibility that GSH, which causes a mechanical feeding response in Hydra (16), might also stimulate budding. This study was designed to test that possibility. The specific objectives were (a) to determine whether exposure to GSH leads to a significant increase in the rate of bud initiation in starved Hydra oligactis, (b) to determine by employing decapitated H. oligactis, whether any observable GSH eflect can occur without mediation by the head of the hydra; and (c) to determine whether any GSH induction of budding is additive to that elicited by feeding. All of these objectives were met, and we propose that GSH plays a (significant) role in the cascade of events heading to budding in Hydra.