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Activation of Starfish Oocytes Modifies their Hormone Dependent Period for 1‐Methyladenine in Meiosis Reinitiation
Author(s) -
Chiba Kazuyoshi,
Hoshi Motonori
Publication year - 1989
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1989.00453.x
Subject(s) - starfish , meiosis , period (music) , microbiology and biotechnology , chemistry , hormone , biology , biochemistry , physics , gene , ecology , acoustics
Starfish oocytes reinitiate the meiosis when they are exposed to the hormone, 1‐methyladenine (1‐MA): 1‐MA must be present for a period of about 10–20 min (20°C) known as the hormone dependent period (HDP). We investigated several conditions which affect the duration of the HDP in the starfish Asterina pectinifera . Fertilization lengthened the HDP about 30–80%, when spermatozoa were added to the oocytes at the same time as 1‐MA was applied. When oocytes were inseminated before 1‐MA treatment, HDP was reduced progressively correlating with the time of the insemination coming earlier, and eventually became shorter than the control. Similarly, A23187 and caffeine lengthened the HDP if they were added to the oocytes at the same time as 1‐MA was applied, and shortened it if they are applied sufficiently in advance to 1‐MA treatment. These modifications of HDP are likely to be brought by changes in the intracellular calcium concentration. A23187 did not lengthen the HDP, if it was administered 10 min after 1‐MA application. Thus the effect of A23187 on the HDP occurred specifically during the first 5 or 10 min after 1‐MA application. These results indicate that the HDP comprises at least two distinct phases.