Partial purification and characterization of the ovulation hormone of the freshwater pulmonate snail Lymnaea stagnalis.

The neurosecretory caudodorsal cells in the cerebral ganglia of the basommatophoran snail Lymnaea stagnalis produce an ovulation hormone (CDCH), which is released from the periphery of the intercerebral commissure. In the present study CDCH has been partially purified, starting with a hydrochloride acid extract of commissures, by gel permeation chromatography on Bio-Gel P-6 followed by cation exchange on SP-Sephadex C-25. This two-step procedure resulted in a ca. 22-fold purification of CDCH. The low purification factor is caused by poor resolution of both purification steps and low recovery on the Bio-Gel P-6 column. With stability tests, proteolytic enzymes, SDS/urea polyacrylamide electrophoresis and isoelectric focussing, purified CDCH was characterized as a stable peptide with a molecular weight of ca. 4700 d and a pI of ca. 9.3. The properties of CDCH are similar to those of the ovulation hormones of opisthobranch snails. Studies on species specificity indicate, however, that it is unlikely that CDCH will cause ovulation when injected in opisthobranchs, or vice versa.