Possible functions of oxytocin/vasopressin-superfamily peptides in annelids with special reference to reproduction and osmoregulation.
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. J. Exp. Zool. 284:401-406, 1999.
Fujino
Y
Y
Department of Biological Science, Faculty of Science, Hiroshima University, Higashi Hiroshima 739-8526, Japan.
Nagahama
T
T
Oumi
T
T
Ukena
K
K
Morishita
F
F
Furukawa
Y
Y
Matsushima
O
O
Ando
M
M
Takahama
H
H
Satake
H
H
Minakata
H
H
Nomoto
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001835:Body Weight; D005260:Female; D007447:Invertebrate Hormones / Q000502:physiology*; D007865:Leeches / Q000502:physiology*; D008969:Molecular Sequence Data; D010121:Oxytocin / Q000031:analogs & derivatives* / Q000502:physiology; D010446:Peptide Fragments / Q000502:physiology*; D010456:Peptides, Cyclic / Q000502:physiology*; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D014882:Water-Electrolyte Balance / Q000502:physiology*
D007447:Invertebrate Hormones; D010446:Peptide Fragments; D010456:Peptides, Cyclic; C076621:conopressin G; C085335:annetocin; D010121:Oxytocin