[Recent knowledge on follicle and oocyte maturation. 2. Oocyte development and maturation].

A review is given about the present knowledge in oocyte development and oocyte maturation. The four parts of the review contain: development of the oocyte in the fetal ovary, morphology and metabolism during meiotic arrest, oocyte maturation, and the relations between oocyte maturation and in vitro-fertilization in the human. The morphological and biochemical changes in the maturation process and present hypotheses about maturation regulation are described especially. The increasing knowledge in this field supports the progress of in vitro-fertilization in the human. On the other hand this technique contributes importantly to new directions in oocyte research.