Possible functions of oxytocin/vasopressin-superfamily peptides in annelids with special reference to reproduction and osmoregulation
✍ Scribed by Fujino, Y.; Nagahama, T.; Oumi, T.; Ukena, K.; Morishita, F.; Furukawa, Y.; Matsushima, O.; Ando, M.; Takahama, H.; Satake, H.; Minakata, H.; Nomoto, K.
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 113 KB
- Volume
- 284
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Annetocin is an earthworm oxytocin-related peptide that we previously isolated from the whole body of a lumbricid earthworm Eisenia foetida. We have reported that annetocin induces egg-laying-like behaviors in E. foetida and a gnathobdellid leech, Whitmania pigra, when it is injected into the respective animals. The present study was undertaken to probe physiological functions of invertebrate oxytocin-vasopressin-superfamily peptides with special reference to reproductive and osmoregulatory events in which vertebrate peptides of this superfamily are involved. Annetocin, Lys-conopressin (a leech vasopressin-related peptide) and two analog peptides, [Tyr 3 ]-annetocin ( 3 Y-annetocin) and [Phe 3 ]-annetocin ( 3 F-annetocin), were compared for their activities to induce egg-laying-like behavior and to change body weight as a measure of water balance in the leech W. pigra. Injection of annetocin, Lys-conopressin, and 3 F-annetocin caused both egg-laying-like behavior and reduction of body weight in the animals, but 3 Y-annetocin induced neither. Furthermore, leeches in the non-breeding season responded to peptides less conspicuously than those in the breeding season. Such a concomitant induction of egg-laying-like behavior and body-weight reduction suggests that these two phenomena are unitary and might be accounted for by the fact that egg-laying in leeches and earthworms is accompanied by secretion of a large quantity of mucus, which should significantly contribute to body-weight loss.