FOLLICLE AND EXTRAFOLLICULAR TISSUE INTERACTION IN ALPHA,20-BETA-DIHYDROXY-4-PREGNEN-3-ONE-STIMULATED OVULATION AND PROSTAGLANDIN SYNTHESISIN THE YELLOW PERCH (PERCA-FLAVESCENS) OVARY
Fw. Goetz, FOLLICLE AND EXTRAFOLLICULAR TISSUE INTERACTION IN ALPHA,20-BETA-DIHYDROXY-4-PREGNEN-3-ONE-STIMULATED OVULATION AND PROSTAGLANDIN SYNTHESISIN THE YELLOW PERCH (PERCA-FLAVESCENS) OVARY, General and comparative endocrinology, 105(1), 1997, pp. 121-126
Intact (attached to extrafollicular (EF) tissue) yellow perch follicle
s ovulate in vitro when stimulated with the steroid, 17 alpha,20 beta-
dihydroxy-4-pregnen-3-one (17,20-PG). However, follicles isolated from
EF tissue will not ovulate under 17,20-PG stimulation. In the present
study, the interaction of follicles and EF tissue in 17,20-PG-stimula
ted ovulation and prostaglandin synthesis was investigated by separati
ng follicles from EF tissue at specific times during incubation. Follo
wing separation, the incubation of isolated follicles and EF tissue wa
s continued. At 48 hr of incubation, isolated follicles were assayed f
or ovulation and the media of isolated follicle and EF tissue incubate
s were assayed by RIA for prostaglandin E (PGE) and prostaglandin F (P
GF) levels. Steroid-stimulated follicles, isolated from EF tissue prio
r to 22 hr of incubation, ovulated less than 25%. However, there was a
very large increase in the percentage ovulation in follicles separate
d from EF tissue from 24 to 32 hr. PGF levels increased significantly
in 17,20-PG-stimulated follicles isolated from EF tissue after 22 hr.
In contrast, mean PGE levels in steroid-stimulated follicle incubates
appeared to be lower than control levels. Compared with controls, PGE
and PGF levels were significantly lower in incubates of isolated EF ti
ssue stimulated with 17,20-PG, and this did not appear to be related t
o the time of separation. The results demonstrate that follicles must
interact with EF tissue for a specific length of time for ovulation an
d PGI: synthesis to occur in isolated follicles. Further, the effects
of 17,20-PG on prostaglandin synthesis appear to be specific for diffe
rent tissue compartments. (C) 1997 Academic Press