allocated to the Georgia. Agricultural. Experiment. Station. Mention. Lexington,. KY 40546-0215. of a trade name, proprietary product, or specific equipment does.
BIOLOGY
OF REPRODUCTION
39, 603-609
(1988)
Absence of Brain Opioid Peptide Modulation Luteinizing Hormone Secretion in the Prepubertal C. RICHARD BARB,2’6 ROBERT R. KRAELING,6
GEORGE MARK
B. RAMPACEK,7 J. ESTIENNE,3’7
ELIZABETH
CYNTHIA
E. ESTIENNE,4’7
TARAS,7 and C. SCOTT
of Gilt’
WHISNANT5’7
USDA -ARS6 Georgia 30613
Athens,
and University
of Georgia7
Athens,
Georgia
30602
ABSTRACT
Three
experiments
luteinizing days
of
age
(NAL),
in
NAL. of age
M gilts
were
oil vehicle (V), resulting received 1 mg/kg BW of
days),
saline
received iv.
was
and
21
of NAL failed mature (M) gilts
ovaries
injected
were
twice
for
in the following groups: NAL on the last day of
I (n=2),
days
or 6 (n=3)
either
PV Blood
vein
(EOP) in modulating (P) gilts, 160-170
and 0.85
mg/kg
cannula
concentrations. (0 VX). At
albicantia
with
PP4 (n=11), treatment.
LH
peptides
I, 8 prepubertal
by jugular
of corpora 10
opioid
3 (n=3),
collected
to alter serum were ovariectomized
devoid
daily
of endogenous In Experiment
role gilt.
either
Blood
All doses
if their
as prepubertal
to evaluate the in the prepubertal
± 10
antagonist,
2 h after days
P and
OVX,
197
=
opiate
before and gifts 160-170 classified
(LH)
(puberty
an
conducted secretion
were
hormone
the
corpora
mg/kg
BW
BW
every
15
of naloxone mm
In Experiment time of 0 VX, lutea.
Three
for II,
guts weeks
2 h 21 P were after
of progesterone
(P4)
(n=10), MP4 (n=11), andMV (n=10). samples were collected via a jugular
or
All gilts cannula
every 15 mm for 4 h before and 2 h after NAL treatment. NAL treatment resulted in an increase (p