Biomaterial Database

Gametogenic processes and their relationship to normal and abnormal conceptus development. 1979

A W Schuetz

The relationship between gametogenesis and conceptus development has been described in relation to recent experiments concerning selected aspects of the cellular and molecular basis of differentiation of female and male gametes. Evidence suggests that a variety of hormonal and nonhormonal mechanisms or combinations thereof have evolved and control distinct stages of oocyte maturation process. Analyses of the meiotic maturation process with particular emphasis on amphibians, indicate that distinct cytoplasmic factors are produced or activated in response to a hormonal stimulus which initiates germinal vesicle breakdown and reinitiates the meiotic maturation process. Evidence suggests that certain cytoplasmic factors originate in the nucleus and (or) cytoplasm and that considerable cytoplasmic maturation proceeds in the absence of the nucleus, or as a result of nuclear-cytoplasmic interactions. Cytoplasmic factor(s) or activities affect many aspects of oocyte function and structure, including the cell membrane, chromosomes, nucleus and meiotic spindle. Ions also play a crucial role in gamete differentiation either alone or in combination with hormones or these cytoplasmic factors. The relevance of these findings to oocyte maturation and fertilization, activation and embryonic development is discussed. In many cases, similar types of biological activities exist in widely separated species and (or) are effective in widely different species. The importance of synchronization of normal gametes to the development of the embryos is discussed. It is proposed, and the evidence suggests, that hormones, ions and cytoplasmic factors play a fundamental and variable role in the differentiation and function of "fully" mature oocytes of many species including mammals. Significantly, the data suggest that a "fully" mature oocyte occurs as a result of the expression of an underlying developmental program. Variations in these substances or the processes involved in their formation or actions appear to be relevant to understanding a wide variety of developmental abnormalities as well as to assessing the normality or abnormality of in vivo or in vitro maturation and differentiation.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008540	Meiosis	A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.	M Phase, Meiotic,Meiotic M Phase,M Phases, Meiotic,Meioses,Meiotic M Phases,Phase, Meiotic M,Phases, Meiotic M
D009865	Oocytes	Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).	Ovocytes,Oocyte,Ovocyte
D009866	Oogenesis	The process of germ cell development in the female from the primordial germ cells through OOGONIA to the mature haploid ova (OVUM).	Oogeneses
D010060	Ovulation	The discharge of an OVUM from a rupturing follicle in the OVARY.	Ovulations
D010063	Ovum	A mature haploid female germ cell extruded from the OVARY at OVULATION.	Egg,Egg, Unfertilized,Ova,Eggs, Unfertilized,Unfertilized Egg,Unfertilized Eggs
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D004622	Embryo, Mammalian	The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.	Embryonic Structures, Mammalian,Mammalian Embryo,Mammalian Embryo Structures,Mammalian Embryonic Structures,Embryo Structure, Mammalian,Embryo Structures, Mammalian,Embryonic Structure, Mammalian,Embryos, Mammalian,Mammalian Embryo Structure,Mammalian Embryonic Structure,Mammalian Embryos,Structure, Mammalian Embryo,Structure, Mammalian Embryonic,Structures, Mammalian Embryo,Structures, Mammalian Embryonic
D004625	Embryo, Nonmammalian	The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.	Embryonic Structures, Nonmammalian,Embryo, Non-Mammalian,Embryonic Structures, Non-Mammalian,Nonmammalian Embryo,Nonmammalian Embryo Structures,Nonmammalian Embryonic Structures,Embryo Structure, Nonmammalian,Embryo Structures, Nonmammalian,Embryo, Non Mammalian,Embryonic Structure, Non-Mammalian,Embryonic Structure, Nonmammalian,Embryonic Structures, Non Mammalian,Embryos, Non-Mammalian,Embryos, Nonmammalian,Non-Mammalian Embryo,Non-Mammalian Embryonic Structure,Non-Mammalian Embryonic Structures,Non-Mammalian Embryos,Nonmammalian Embryo Structure,Nonmammalian Embryonic Structure,Nonmammalian Embryos,Structure, Non-Mammalian Embryonic,Structure, Nonmammalian Embryo,Structure, Nonmammalian Embryonic,Structures, Non-Mammalian Embryonic,Structures, Nonmammalian Embryo,Structures, Nonmammalian Embryonic
D005260	Female		Females