Artículo de revista
Ultrastructure of bovine ovarian follicles induced to extended growth by perioestrous suprabasal progesterone levels
Fecha
1996Registro en:
Acta Veterinaria Scandinavica, Volumen 37, Issue 3, 1996, Pages 239-250
0044605X
Autor
Duchens, M.
Rodríguez Martínez, H.
Forsberg, M.
Gustafsson, H.
Institución
Resumen
The present study was undertaken to determine if a short-term prolonged growth of the ovulatory follicle (12 to 18 h after expected time of ovulation), induced by progesterone implants, would cause ultrastructural changes in the follicular wan. Oestrous behaviour, follicular growth, follicular and blood plasma levels of oestradiol-17 beta, progesterone and plasma luteinizing hormone (LH) were monitored in heifers oophorectomized at 9 to 12 h (controls) or 36 h after the onset of oestrus, in order to sample the prl-ovulatory follicle present. The suprabasal plasma progesterone concentrations (approximately 1.2 nmol L(-1)) allowed expression of oestrus at the expected time, but ovulation was delayed owing to the absence of a LH-surge. The resulting prolongation of follicle growth was associated with mild degenerative changes in the follicle wall, i.e. both granulosa and thecal cells presented increased electron density, higher amounts of secondary lysosomes and lipid droplets, increased intercellular spaces with presence of debris. No signs of luteinization were seen.