The Endocrine Pathway Responsible for Oocyte Maturation in the Inarticulate Brachiopod Glottidia

An aqueous extract of lophophore from Glottidia pyramidata induces oocyte maturation and follicle cell retraction in pieces of ovary and spawning in intact animals. The extract does not act directly on large oocytes but indirectly, through some other cell type in the ovary. The activity of the extract is insensitive to boiling or protease treatment and passes through a filter with a molecular weight cutoff of 2000. Bromoadenosine 3'5' cyclic monophosphate and dibutyryl 3'5' cyclic monophosphate have the same oocyte-maturing and spawning-inducing properties as lophophore extract. The active component in lophophore extract presumably affects somatic cells in the ovary, stimulating a rise in cyclic monophosphate levels in these cells, which then secrete a factor that causes oocyte maturation.