A. Krishna et S. Abhilasha, Proliferative activity of follicles and serum steroid concentration in Scotophilus heathi (vespertilionid bat) during periods of delayed ovulation, CAN J ZOOL, 78(8), 2000, pp. 1301-1308
Citations number
32
Categorie Soggetti
Animal Sciences
Journal title
CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE
Follicular kinetics were studied using immunocytochemical localization of p
roliferating cell nuclear antigen (PCNA) and changes in circulating steroid
concentrations to investigate the cause of prolonged survival of Graafian
follicles and delayed ovulation in the vespertilionid bat Scotophilus heath
i. PCNA immunoreactivity was limited to the granulosa cells and varied with
stage of follicular development and reproductive phase. Two waves of folli
cular growth appear to be initiated in October and February. The first wave
resulted in the appearance of some late antral follicles in November. Thes
e antral follicles grew slowly and differed from typical mammalian Graafian
follicles, as the cells of their cumulus oophoricus were large and hypertr
ophied. The second wave of follicular development resulted in fresh recruit
ment and selection of dominant follicles in February. The steroid-hormone p
rofile showed an unusually high concentration of circulating androstenedion
e from October to December. The estradiol concentration showed two peaks co
inciding with two peaks of PCNA immunoreactivity. The results show that the
unusually high androstenedione concentration might be responsible for the
development of non-ovulatory Graafian follicles with hypertrophied granulos
a cells, which survive for a prolonged period. The decline in androstenedio
ne concentration allows the development of ovulatory follicles in S. heathi
.