Regional Differences in Methyl Farnesoate Production by the Lobster Mandibular Organ

• Published in: The Biological bulletin (Lancaster) Vol. 186; no. 1; pp. 9 - 16
• Main Authors: Borst, David W., Tsukimura, Brian, Laufer, Hans, Couch, Ernest F.
• Format: Journal Article
• Language: English
• Published: United States Marine Biological Laboratory 01.02.1994; University of Chicago Press
• Subjects: American lobster; Animal glands; B lymphocytes; Cell Biology; Cells; Crabs; Crustaceans; Endocrine cells; Histology; Homarus americanus; Hormones; L cells; Lobsters; Mandible; Marine; Mouth; Physiological aspects; Shellfish; Vacuoles
• ISSN: 0006-3185; 1939-8697
• DOI: 10.2307/1542032

Visual examination of the mandibular organ (MO) from the lobster, Homarus americanus, disclosed two distinct morphological regions: a fan-folded region along one edge of the gland, and a smooth, unfolded region comprising the rest of the gland. Because MOs produce methyl farnesoate (MF), the MF content of both regions was measured. In freshly dissected glands, more than 95% of the MF was found in the fan-folded region of the gland. In MO sections incubated with [3 H-methyl] methionine (a radiolabeled precursor of MF), more than 90% of MF synthesis was found in the fan-folded region. Eyestalk ablation, a procedure that increases MO activity, caused the MF content of MOs to increase more than 130-fold, but had little effect on the regional distribution of MF. Histological observations indicated that these two regions had different cellular compositions. The fan-folded region contained two cell types (A and B). The A cells were mitotically active and appeared to be undifferentiated. The B cells contained a large number of small vacuoles. The unfolded region was largely composed of a third cell type (C). The C cells were large and morphologically complex, containing many mitochondria and large vacuolar-like structures. They contained relatively few small vacuoles. On the basis of appearance and location, B cells appear to be the likely site of MF synthesis. The physiological importance of C cells is unknown.