CHANGES IN THE ELECTROPHORETIC PATTERN OF YOLK PROTEINS DURING VITELLOGENESIS IN THE GILTHEAD SEA BREAM, SPARUS-AURATA L

1. To some extent, oocyte growth within a follicle is due, as well as to the accumulation of normal cytoplasmic components, to that of the cortical alveoli, and of hepatic-derived protein (vitellogenins). 2. Yolk proteins of pre-maturational oocytes at different stages and ovulated eggs were compared by SDS-gel electrophoresis. The largest components stained by Coomassie Blue and those stained by Stains-all, which had formed during vitellogenesis, either disappeared or diminished, whilst smaller components appeared. 3. The distinct changes in yolk-protein banding patterns during oocyte maturation are suggestive of extensive secondary proteolysis of yolk proteins.