Development of the germinal ridge and ovary in the African elephant (Loxodonta africana).
Reproduction
; 144(5): 583-93, 2012 Nov.
Article
en En
| MEDLINE
| ID: mdl-22991581
The follicular reserve and its ontogeny in the elephant are of interest because elephants have the longest reproductive life of all land-based mammals. They also have the longest recorded pregnancy, which allows a protracted view of the series of significant events involved in the development of the embryonic and fetal gonads. The large elephant population of Zimbabwe provided the opportunity to collect conceptuses from elephants culled for management reasons and hunted professionally. Five embryos aged 76-96 days and the ovaries of four fetuses aged 4.8-11.2 months were fixed in 4% buffered formalin and studied by conventional histological sectioning and a stereological protocol to calculate the follicle reserve of each fetus. These observations enabled the conclusion that the migration of primordial germ cells into the indifferent gonad terminates at around 76 days of gestation while entry of oogonia into meiosis along with first follicle formation starts at around 5 months. Peak numbers of follicles are present by mid-gestation towards the end of the 6-month mitotic-meiotic transition period. It appears that the cortex of the elephant fetal ovary at mid-gestation (11 months) has already reached a developmental stage exhibited by the ovaries of many other mammals at full term.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ovario
/
Elefantes
Límite:
Animals
/
Pregnancy
País/Región como asunto:
Africa
Idioma:
En
Revista:
Reproduction
Asunto de la revista:
MEDICINA REPRODUTIVA
Año:
2012
Tipo del documento:
Article
País de afiliación:
Zimbabwe
Pais de publicación:
Reino Unido