Jun 11, 1992 - Blackthurg. Virginia. 24061. Department of Animal. Science,4. University of Minnesota,. St. Paul,. Minnesota. 55108. Department of Biology,5.
OF
BIOLOGY
47, 598-602
REPRODUCTION
Pituitary
Luteinizing Inversely ERIC
JANET
of Animal
Department Department
and Prolactin
Related
A. WONG,2’3
Department
(1992)
Hormone
in Laying
L. SILSBY,4
Science,3
of Animal
of Biology,5
Ribonucleic
and Incubating
SUSUMU
Virginia
ISHII,5
and
Turkey
University
and
of Minnesota,
of Education,
Waseda
Levels
Are
E. EL HALAWANI4
State
University,
St. Paul,
University,
Acid
Hens1
MOHAMED
Polytechnic Institute Virginia 24061
Science,4
School
Messenger
Blackthurg
Minnesota
Shinjuku-ku,
55108 Tokyo
160,
Japan
ABSTRACT The hens
relationships
at different content
PRL
6-fold,
phase.
not
did
of UI-K
In the
mRNA
were
low.
levels
and
hens.
as dramatically.
PRL
and
shows
three PRL
to PRL
levels,
to its lowest in incubating
that
Factors
seem
gonadotropic there and
PRL
to of
function, a number
In
unknown.
states,
tend
capable
increase
prolactin
suppressing
control
Secretion
relationship
between
of
bating
of PRL in the reviewed by
the
tion
of
and
PRL
gonadotropins
lactation
hyperprolactinemia UI
levels
verse
related
minished [10, 11],
secretions
From
PRL
levels
a number
[15], and
and
of
physi-
[7], turkeys [13], ring spotted
depressed
in-
13 mRNA
is asso-
levels
PRL
and
hens
barely
detectable
Animal
of incu-
Accepted
by USDA
grants
#88-37242-03845
Dr. Eric A. Wong, Department
2Correspondence: Institute
and
State
University,
Blacksburg,
of Animal
Science,
VA 24061-0306.
Virginia
FAX:
(703)
Turkey
periments. The nonphotostimulated, photorefractory were maintained
and
91-37203-6609. technic
exogenous
PRL suppresses
secretion
that
chickens
occurs are
after deprived
between plasma PRL and relationship may exist
UI
the
corre-
levels of pituitary [H 13-subunit (m) RNA with pituitary and
serum
the
genes.
To
determine
UI for
of turkey
pituitaries
(UI-
hens
at dif-
cycle were analyzed hens maintained high
and low PRL mRNA dramatically elevated UI-13 mRNA levels.
levels, whereas PRL mRNA levels
on UI-
incuand
Poly231-
6L:18D
3010.
598
AND
METHODS
Studies
Hatchmate
in part
[22]. of PRL levels results in corUI. The injection of PRL antiincrease in UI levels in incu-
incubating
MATERIALS
cholas June 11, 1992. Received January 17, 1992. tThese studies were supported
deprivation [17-20], the pharmacological
di-
[16].
levels
and
from
had
mRNA Pituitary
hens.
by nest [211, or
in UI
or when
levels
bating
3-, and
-subunlt
turkey
[20]. relationship a comparable
[8,9], ducks doves [14],
sandpipers UI
incubating
[23]. Furthermore,
RNA
in-
80-,
mRNA abundance was highest results demonstrate that the abun-
phases of the reproductive Northern blots. Photostimulated
secretion activity
total
the
57-fold
phases.
ferent
an
gonadotropin
of incubation circulating
levels,
during
UI-B
lation of the steady-state 13) and PRL messenger
controlled
conditions,
PRL and
The onset enhanced
are
UI
pituitary
synthesis
of PRL
and
declined
reproductive
increase
nests inverse that
peaked 11-,
levels
be reversed of chicks
[24]
expression
by diminished
reproductive
between
sparrows
elevated
inappro-
[4-6].
UI levels in bantam hens canaries [12], wild starlings
white-crowned
of
chickens
observed
of their The suggests
experimental
is accompanied
gonadotropin
experimental
to emerge. with greatly
stages
Additionally,
mechanisms.
relationship
seems ciated
The
sexes
PRL and
or
ological
[3].
in rats
in both
In birds, by closely
during
in women
and
of serotonin
ovariectomy
McNeilly [1]. During postpartum lactation in rats, serum PRL is high whereas serum UI and FSH are relatively low [2]. A similar relationship appears to exist between the secrepriate
peak
different
and
and
for turkey and pituitary
serum
220-,
Experimental manipulation responding changes in serum serum is associated with an
is
secretion
The role has been
LII,
the
hens. Pituitary hens. These
blockade
although the precise mechanism of reproductive and pathological
is an inverse
pituitary for
bating hens can the introduction
hypothalamic-pituitary
secretion of gonadotropins. of gonadotropin secretion
UI,
changes
determined
hen,
showed
These
in photostimulated/laying
relationship
(PRL)
hens
respectively.
serum
were
inactive
photostimulation
incubating
level in incubating and photorefractory
INTRODUCTION
also
after
rose
levels,
mRNA
content
reproductively
values
no significant
showed
an inverse
PRL
pituitary
and
hyperprolactinemic
pituitary
LII
and declined hens and lowest
mRNA
All
In contrast
Serum
to serum
RNA
nonphotostimulated,
hens,
content,
PRL
photostlmulation and laying
(m)
messenger
UI
cycle.
in photorefractory
change
LU peaked after In photostimulated dance
and
reproductive
to nonphotostimulated
pituitary
PRL,
respectively,
levels
PRL
Relative
in serum
(PRL)
of the
pituitary
and
Incubation creases
of prolactin phases
turkeys
of the
Farms,
Sonoma,
large
white
CA) were
female used
line
reproductive groups used in this study photostimulated, laying, incubating, hens. Quiescent or nonphotostimulated under a nonstimulatory photoregimen
for at least
8 wk.
These
birds
possessed
(Ni-
for these
exwere and hens of
a regressed
AND
LII
ovary
and
oviduct
and
to a stimulatory switched from
would
hens
the
and six
nest
or
reproductive
aggressive nest protection were allowed to progress to
where
and
migration
LH-13,
on
were
stripped
and
from
and
citrate,
from
ladder
and
pH
A. LH mRNA NPS PS 12345678
L
PR 910
‘-0.9kb B. PRL mRNA ‘-3.1kb
laying
7.0;
with
and
Turkey
at
pituitar-
turkey
gels containing were based on kb; to
1.0%
Gene action
Columbia,
normalized LH-13 and
and chicken as described prefirst with chicken PRL,
and
finally
to
LH-13
and
to 13-actin mRNA levels PRL by the ADU for [3-actin
or six different were analyzed,
‘-2.0kb
PRL,
corresponding
MD).
mRNA
Screen and hy-
SDS.
(ADUs)
C. 6-actin
GIBCO-BRL,
for LH-13, PRL, and 13-actin mRNA by densitometry (Shimadzu CS 90004
Shimadzu,
as mean
hens in liquid
isothiocyanate RNA were loaded
(0.24-9.5
units
determined
levels were ADU5 for
turkey
with chicken 13-actin. Membranes for 30 mm in 0.015 M NaCl; 0.0015
of hybridization
each sample. Five ductive condition
samples for each and the results
FIG. 1. Northern blot of pituitary LH, prolactin, and -actin mRNA abundance. Total RNA was extracted from individual pituitaries of turkey hens at different stages of the reproductive cycle. Two replicate hens from each reproductive phase are shown: nonphotostimulated (NPS). lanes 1 and 2; photostimulated (PS). lanes 3 and 4; laying (L), lanes 5 and 6; incubating (I), lanes 7 and 8; and photorefractory (PR), lanes 9 and 10. A) The blot was probed with a radiolabeled chicken LH cDNA. Exposure time was 2 days. B) The blot was stripped and reprobed with turkey PAL eDNA. Exposure time was 16 h. C) The blot was again stripped and reprobed with chicken -actin cDNA. Exposure time was 2 days.
PRL
by for
reproare re-
Institute,
Cary,
identifIed cances
NC).
by use were
Significantly
of Duncan’s
reported
at p