Absence of Brain Opioid Peptide Modulation of Luteinizing Hormone ...

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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