title: Regional differences in the pattern of vitellogenesis in the painted frog Discoglossus pictus.
abstract: During oocyte growth in the frog Discoglossus pictus two patterns of vitellogenesis are described. The first one consists of the transformation of multivesicular bodies into yolk platelets; the second is the result of a typical endocytotic process, as described in other species. The peculiarity in Discoglossus vitellogenesis consists of a regional difference of these features of vitellogenesis in vitellogenic oocytes: the multivesicular bodies transforming into yolk platelets are found only in the germinative area--the central portion of the animal half--whereas deep crypts with numerous endocytotic pits are found only in the vegetal half. The probable meaning of this regional difference in vitellogenic oocytes is discussed.
mesh_terms: D000818:Animals; D001001:Anura / Q000033:anatomy & histology / Q000502:physiology*; D004530:Egg Yolk; D005260:Female; D009865:Oocytes / Q000254:growth & development / Q000648:ultrastructure