Influence of gonad-stimulating substance on ovarian 1-methyladenine levels responsible for germinal vesicle breakdown and spawning in the starfishAsterina pectinifera
✍ Scribed by Mita, Masatoshi ;Nakamura, Masaru
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 514 KB
- Volume
- 269
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
In starfish oocytes, 1‐methyladenine (1‐MeAde) induces not only germinal vesicle breakdown (GVBD) but also follicular envelope breakdown (FEBD), releasing the oocytes from the ovaries, i.e., spawning. This study was undertaken to examine changing levels of 1‐MeAde within ovaries of the starfish Asterina pectinifera after treatment with gonad‐stimulating substance (GSS). 1‐MeAde production in ovaries was markedly dependent on GSS concentration. Although the period until oocyte release from the ovaries was shortened to as little as 19 min when the GSS concentration was increased to 0.1 mg/ml, about 5 min of treatment with GSS (0.1 mg/ml) was sufficient for induction of oocyte release, involving GVBD and FEBD. Almost the same duration of treatment with 1‐MeAde at a concentration of 0.1 μM was required for spawning. Since the increase in the 1‐MeAde level was correlated with a parallel rise in ovary wet weight, the internal content of 1‐MeAde in ovaries was estimated to be 1 g wet weight ovary/ml. The content of 1‐MeAde within the ovaries was calculated to reach about 0.18 μM during 5 min of GSS treatment. It is thus concluded that the 1‐MeAde content is sufficient to induce GVBD and FEBD of oocytes in starfish ovary. © 1994 Wiley‐Liss, Inc.