An in vitro bioassay for a mulluscan gonadotropin

Area of Science:

• Reproductive biology
• Endocrinology
• Marine invertebrate physiology

Background:

• Protein synthesis is crucial for ovarian development in Octopus vulgaris.
• The optic glands are known to influence reproductive processes in cephalopods.

Purpose of the Study:

• To investigate the role of optic glands in regulating ovarian protein synthesis in Octopus vulgaris.
• To explore the potential of measuring amino acid incorporation as a biological assay for optic gland hormone activity.

Main Methods:

• Measuring [14C]leucine incorporation in vivo and in vitro.
• Assessing the effect of optic gland removal and optic gland extract on amino acid incorporation.
• Utilizing electron microscopy to identify the site of protein synthesis.
• Analyzing the kinetics of leucine uptake and incorporation.

Main Results:

• Optic gland removal significantly reduces ovarian protein synthesis.
• Optic gland extract stimulates amino acid incorporation in vitro.
• The hormone affects leucine transport independently of protein synthesis.
• Follicle cells are identified as the primary site of protein synthesis.

Conclusions:

• Optic glands secrete a hormone that stimulates ovarian protein synthesis in Octopus vulgaris.
• Amino acid uptake and incorporation by follicle cells can serve as a sensitive assay for this hormone.
• This assay may be applicable to other molluscan gonadotropins.