induced spawning
123
resorbtion without
maturation
in
the non responding ones (JALABERT et al.
1977).
Although
ovaries
are
ready to spawn they are able to respond to a GtH
stimulation since
an
increase
in plasma estradiol (178 E2) is noticed when
compared to
levels
before
injection (FOSTIER et al.
1979, WEIL et al.
1980,
KIME and
DOLBEN
1985). Serial samplings have shown that 178 E2 are low du—
ring the
first
3 hours following priming and then begin to increase 5 hours
after the injection. Maximal values are attained 12 hours later (WEIL et al.
1980). However
mean
178
E2
levels
are
not
increased
following the second
injection (WEIL
et
al.
1980, KIME and DOLBEN 1985). This increase in 178 E2
might be
due
to
the
presence
of vitellogenic oocytes since at the time of
ovulation oocytes
of all
stages are present (BIENIARZ et al.
1977). The in—
crease
in
178 E2 levels following priming is preceded by an increase in tes—
tosterone which
is
consistent
with
a
precursor product relationship. The
second injection
of pituitary extract did not lead to a massive increase in
testosterone
related
to
the
increase
in GtH
but greater amounts of glucuronides were observed
(KIME and DOLBEN 1985).
Concerning progestins KIME and DOLBEN (1985) observed detectable levels
of
17a
hydroxyprogesterone (17@0H P) before injection and an increase after
hypophysation. Peak
height varied from 1.6 to 13,3ng/ml and dropped rapidly
after ovulation.
On
the other hand
they observed no detectable levels of 17d
208 DH P
except in one fish. Levels were 1,08ng/ml at the time of ovulation
and 0,11
and
1,14ng/ml respectively 6 and 3 hours before ovulation. We must
emphasize the
fact
that
the
treatment of hypophysation induced only partial
ovulation
in
all
the
fish.
In
a
work
conducted
in our
laboratory blood
samples were
taken
every
3 hours for 30 hours on 7 females submitted to hy—
pophysation (100
ug/kg
of partially purified carp GtH). Two fish have com—
pletely ovulated,
2
partially
and
the
remaining three have not ovulated.
(fig. 1).
8
E
E,
7
C
0
g
5
2
noovulatlon
;
"…“
&
5
[
1
0
CL
A
—°—’
4
U
ovu lation
'
'
€
0
6
12
18
24
30
'à 3
HOURS
0
N
\
><
2
2 partial ovulation
E
“D
>—
F
1
1
L‘
!
’
"
Q
.—0
0
6
1215
24
30
0
6
1218
24
30
GLH
HOUHS
Figure 1
:
Plasma
17a 208 DH P in female carp following hypophysation.
123
resorbtion without
maturation
in
the non responding ones (JALABERT et al.
1977).
Although
ovaries
are
ready to spawn they are able to respond to a GtH
stimulation since
an
increase
in plasma estradiol (178 E2) is noticed when
compared to
levels
before
injection (FOSTIER et al.
1979, WEIL et al.
1980,
KIME and
DOLBEN
1985). Serial samplings have shown that 178 E2 are low du—
ring the
first
3 hours following priming and then begin to increase 5 hours
after the injection. Maximal values are attained 12 hours later (WEIL et al.
1980). However
mean
178
E2
levels
are
not
increased
following the second
injection (WEIL
et
al.
1980, KIME and DOLBEN 1985). This increase in 178 E2
might be
due
to
the
presence
of vitellogenic oocytes since at the time of
ovulation oocytes
of all
stages are present (BIENIARZ et al.
1977). The in—
crease
in
178 E2 levels following priming is preceded by an increase in tes—
tosterone which
is
consistent
with
a
precursor product relationship. The
second injection
of pituitary extract did not lead to a massive increase in
testosterone
related
to
the
increase
in GtH
but greater amounts of glucuronides were observed
(KIME and DOLBEN 1985).
Concerning progestins KIME and DOLBEN (1985) observed detectable levels
of
17a
hydroxyprogesterone (17@0H P) before injection and an increase after
hypophysation. Peak
height varied from 1.6 to 13,3ng/ml and dropped rapidly
after ovulation.
On
the other hand
they observed no detectable levels of 17d
208 DH P
except in one fish. Levels were 1,08ng/ml at the time of ovulation
and 0,11
and
1,14ng/ml respectively 6 and 3 hours before ovulation. We must
emphasize the
fact
that
the
treatment of hypophysation induced only partial
ovulation
in
all
the
fish.
In
a
work
conducted
in our
laboratory blood
samples were
taken
every
3 hours for 30 hours on 7 females submitted to hy—
pophysation (100
ug/kg
of partially purified carp GtH). Two fish have com—
pletely ovulated,
2
partially
and
the
remaining three have not ovulated.
(fig. 1).
8
E
E,
7
C
0
g
5
2
noovulatlon
;
"…“
&
5
[
1
0
CL
A
—°—’
4
U
ovu lation
'
'
€
0
6
12
18
24
30
'à 3
HOURS
0
N
\
><
2
2 partial ovulation
E
“D
>—
F
1
1
L‘
!
’
"
Q
.—0
0
6
1215
24
30
0
6
1218
24
30
GLH
HOUHS
Figure 1
:
Plasma
17a 208 DH P in female carp following hypophysation.