In the present work we report some variations in glucose and glycogen content as observed during sea urchin (L. variegatus) embryo development until blastula stage. Wild specimens were collected in Búzios (RJ – Brazil), and in vitro fertilization was promoted by mixing male and female gamets in natural filtrated sea water at 21°C. Embryo development was monitored by light microscope. We didn’t succeed to observe developmental stages further blastula (≈ 7.5 hours after fertilization).

All determinations were carried out in egg homogenates from each stage, obtained in 100mM PBS, pH 7.4. Glucose and glycogen were enzymatically determined and their contents demonstrated an increase at morula stage (≈ 2.5 hours after fertilization). It suggests the de novo synthesis reactions for these energetic compounds. The glycogen synthesis involves the glycogen synthase inhibition by the glycogen synthase kinase 3 (GSK3). GSK3 is a multifunctional serine/threonine kinase found in all eukaryotes, and already described in sea urchin. GSK-3β has also been identified as a regulator in a well-established component of the Wnt signaling pathway, which is essential for setting up the entire body pattern during embryonic development in Drosophila melanogaster. Akt (protein kinase B) is a protein kinase integrating the insulin signaling pathway in mammals that has been recently related to invertebrate development.

Further studies will helps us to better understand the importance of glucose metabolism in invertebrate development as well as the role of GSK3 and Akt.

Supported by CNPq, PRONEX and FAPERJ