Role of asterosaponin A in starfish spawning induced by gonad-stimulating substance and 1-methyladenine

✍ Scribed by Ikegami, Susumu

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 773 KB
• Volume: 198
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401980309

✦ Synopsis

Abstract

A polypeptide hormone, gonad‐stimulating substance (GSS), induces oocyte maturation and spawning in starfish through the production of 1‐methyladenine (1‐MA) in the follicle cells. Asterosaponin A (ASA) obtained from the ovary of Asterias amurensis inhibits the spawning induced by the application of GSS on isolated ovarian fragments of Asterias. The action of ASA is not ascribable to its surface‐active property since various natural and synthetic surface‐active agents failed to affect GSS‐induced spawning. ASA antagonized the action of 1‐MA in inducing spawning of isolated ovarian fragments. However, ASA did not inhibit 1‐MA‐induced maturation of isolated oocytes. When ovarian fragments were placed in sea water containing ASA and GSS or 1‐MA, oocytes inside the fragments underwent germinal vesicle breakdown. The application of acetylcholine to these ovarian fragments resulted in an immediate shedding of mature oocytes. ASA did not affect calcium‐induced spawning in the ovarian fragments which were pretreated with calcium‐free sea water to dissolve the follicular envelope.