High titers of ecdysteroids are associated with the secretory process of embryonic envelopes in the european lobster.
The newly laid egg of the lobster Homarus gammarus is surrounded by a vitelline coat. Just after fertilization, a new subjacent envelope (2), originating from the cortical reaction, is deposited beneath the vitelline coat. In the course of embryonic development, five new coatings (envelopes 3 to 7) are secreted successively from the ectodermal embryonic cells. These will remain until hatching, freeing the mysis larva in concentric order without exuviation. The concentration of both the two major ecdysteroids (ponasterone A and 20-hydroxyecdysone) and their respective precursors (25-deoxyecdysone and ecdysone) were determined as a function of the secretory phase for three embryonic envelopes (2, 3 and 6). We determined that the secretory processes proceed in the presence of high titers of 20-hydroxyecdysone during the onset of envelope secretion and of ponasterone A in the last phase of secretion.
Goudeau
M
M
Ecole Normale Supérieure, CNRS URA 686, Laboratoire de Biochimie et Physiologie du Développement, 46 rue d'Ulm, 75230 Paris Cedex 05 France; Station Biologique 29211 ROSCOFF; CEN Saclay, Gif sur Yvette, 91191 Cedex, France.
Lachaise
F
F
Carpentier
G
G
Goxe
B
B