Aug 20, 1986 - hormone. (LH) and follicle-stimulating hormone. (FSH) to chronic gonadotropin-releasing hormone-agonist. (GnRH-A) treatment is substantially.
BIOLOGY
OF
REPRODUCTION
36,
309-313
(1987)
Testicular Modulation of Luteinizing Hormone Response to GonadotropinReleasing Hormone (Gn RH )-Agon 1st Treatment SHALENDER URIEL
BHASIN,’
THOMAS
A. SOD-MORIAH,
and
Division
S. SWERDLOFF
of Endocrinology
Department Harbor-
J. FIELDER,
RONALD
of Medicine
UCLA
Torrance,
Medical
Center
California
90509
ABSTRACT We hormone
and
others (FSH)
ferent
in normal
have observed that the response to chronic gonadotropin-releasing
of serum luteinizing hormone-agonist
compared
These
to hypogonadal
the gonadotropin response mediated by products of
to GnRH-A. the interstitial
with
selective
of interstitial,
were
divided
bilaterally
impairment into
five
cryptorchid;
impairment
of
Unlike treatment,
impairment GnRH-A tubular
the
function),
testicular the tubular
behaved that
modulation compartment.
1)
or both
castrated;
while
ketoconazole injections 4 wk.
which animals
showed showed
regulate
of gonadotropin
intact
castrated
analogs of gonadotropin-releasing have generated a great deal
of
GnRH-A
the course in man, cancer,
of other we noted who tend
studies with these that older patients to be hypogonadal
of
have
mature
of
an
patients. following determine
tubular
August 20, 1986. April 21, 1986. requests.
selective compartments 309
shown
the
5 groups GnRH
IV, to
was
have
divided
agonist,
suppression T biosynthesis
elevation
of
LH of
at least
in part,
to GnRH-A status of
D-
modulation products
GnRH-A
GnRH-A by
and
products
of testes.
2) of
(Heber et a!., to suppressive hormone-agonist
(LH) that
than younger the difference
be attributed function
to the of these
prompted us to ask the Does testicular function to GnRH-A? 2) If so, is
of
we assessed experimental of the
after
of LH response of the interstitial
compartments
impairment
of LH after and intact
women sensitive
could gonadal
These observations questions: 1) the LH response
the testicular mediated by
agonist with as a
rats
implants;
a potent
administration
mediated,
in LH response pretreatment
effect is states Wistar
(T) been
and post-menopausal were much more of gonadotropin-releasing
hypothesis, rats with Accepted Received Reprint
sexually
dif-
determine
concentration after 4 wk of GnRHbaseline. Animals with preferential
chronic be
testes
(GnRH-A) on luteinizing hormone male volunteers. We hypothesized
because of their potential as male contraceptive agents (Linde et al., 1981; Schurmeyer et al., 1984; Bhasin et al., 1985) and as treatment for a variety of hormone-sensitive disorders such as prostate cancer (Warner et al., 1983), precocious puberty (Crowley et al., 1981), endometriosis (Meldrum eta!., 1982), and polycystic ovarian disease (Steingold et al., 1986). During analogs prostate
to may
group, 1981) effects
hormone interest
Each
LH below
the
testosterone
1 jig
demonstrated
response to
male animals
or serum
of
+ T) also showed significant animals (with inhibition of
and
INTRODUCTION Agonist (GnRH)
saline
of basal suppression
animals
100 20-mm
Ciyptorchid
follicle-stimulating is substantially
determine whether this To create experimental
to
compartment. with
(LH) and treatment products
T biosynthesis.
either
gonadotropin response
designed
castrated
inhibits
an elevation significant
that
compartments,
III,
of
(cryptorchid and the ketoconazole-treated to
suggested
animals.
daily for
similarly testes
tubular, II,
data
studies were or the tubular
ketoconazole-treated
function
of tubular function treatment. However,
treatment. We conclude
V,
to receive N-ethylamide,
intact animals, the castrated
The present (steroids)
1, intact;
and
tubular
into 2 subgroups leu6des-G1y10GnRH A
groups:
males.
hormone (GnRH-A)
the
gonad?
the LH response lesions designed tubular,
interstitial,
to GnRH-A (steroids) or To to
test
this
of
male induce
or both
310
BHASIN
MATERIALS Study
AND METHODS
hundred into
male sexually mature 5 groups: I, in act;
H,
Wistar rats castrated;
were III,
castrated animals with 20-mm testosterone (T) implants; IV, bilaterally cryptorchid animals; and V, ketoconazole-treated animals. Experimental cryptorchidism has been shown to result
in preferential
impairment
with relative preservation (Swerdloff et al., 1971). shown by us and others inhibit
T biosynthesis
Organ frozen
24
h
for the
the
last
recorded,
by
was administered i.m. injection
Sikka
et a!.,
organs
in
the
All
initiation
concentration were measured
NIADDK.
IntraRIAs 2.6
The
rat
(Bhasin
et
a!.,
created et al.,
by methods 1979), 2 wk
treatment.
of rat by
minima!
and were and
interassay as follows:
LH (rLH) reagents
detectable
LH radioimmunoassay RP-2 and for FSH
was
and rat supplied
concentration
(RIA) was 0.75 ng/m!
coefficients rLH ± 3.1
FSH by for
0.05 ng/ml of of rFSH RP-2.
of variation and 11.0%;
for the rFSH ±
12.0%.
T was described Serum
of GnRH-A
measured previously was
extracted
in
extracted (Fundenburgh with
10
and
variation
8.3%,
±
expressed
by
for
the
serum
T
respectively.
as mean
analysis
of
SEM.
±
variance
using
Data the
were BMDP
1985).
(Dixon,
RESULTS
Body between
treated decrease
serum
Measurements
Serum (rFSH) the rLH
was Kretser
are software
weights the GnRH of the
serum et volumes
by a!.,
RIA as 1983). of
ethyl
were not significantly agonistor saline-treated
of
Table tions.
prostate
1, closely In controls,
were low cryptorchid
and and
seminal
paralleled the cryptorchid,
groups, GnRH-A in serum T
Castrated suppression decline castrated
different animals
5 groups.
Serum T concentrations ketoconazole-treated,
in the castrated, animals. The
vesicles, serum and
shown
in
T concentraketoconazole-
treatment led to a significant and accessory organ weights.
animals had already achieved maximal of serum T and showed no further with GnRH-A treatment. In T-replaced animals, T implant prevented any further
decline in serum T after GnRH-A treatment. All the groups behaved true to expectation, thus establishing the validity of our experimental mode!. Examination of representative sections of testes from
ever,
Hormone
data
statistical
was
the
injection.
Cryptorchidism cryptorchidism described (de
of
RIA. and
Analysis
the
normal animals
Bilateral previously
3.9%
analyzed
weights
1986).
before
were
Statistical
the by
in corn oil at a 3 times a day for the
male
±
the end of were killed
treatment period. This dose of ketowas shown in previous experiments to effectively serum testosterone and weights of sex
assay
in any
4-wk
accessory
coefficients
divided into 2 of either saline D-leu6 desGly’#{176}
GnRH-A and
interassay
(3:2 v/v) prior to over 90%. Intra-
function function has been and directly
1982;
wk. At animals
hexane mixture were consistently
cell
Administration
Ketoconazole dose of 25 mg entire conazole inhibit
4
after
weights were at -20#{176} C.
Ketoconazole
et al.,
5 groups was daily injections GnRH agonist
GnRH-EA (GnRH-A) 4-wk treatment period, decapitation
of tubular
of Leydig Ketoconazole to selectively
(Pont
1985). Each of the subgroups to receive or 1 jig of a potent
AL.
acetate and Recoveries
Design
One divided
ET
control
animals
testicular also had the
by light
histology. normal
cryptorchid
microscopy
revealed
The ketoconazole-treated testicular histology.
testes
revealed
the germinal epithelium, hyalinization tubules, and Leydig cell hyperplasia. The serum LH response to GnRH-A
How-
degeneration of some
of of the
is shown
as
absolute values corresponding Intact animals
in Table 1 and as percentage of saline-treated controls in Figure 1. showed significant elevation of basal
LH concentrations Saline-treated
after castrated
significantly
elevated
compared castrated sensitivity
4 wk of GnRH-A treatment. animals, as expected, had basal
LH
to intact controls. GnRH-A animals again demonstrated to the suppressive effects
concentrations treatment of their exquisite of GnRH-A.
Cryptorchid animals with preferential impairment of tubular function also showed significant suppression of LH after GnRH-A treatment. However, ketoconazole-treated animals with inhibition of
TESTES TABLE
1. Effects
of GnRH-agonist
MODULATE
(GnRH-A)
treatment
Intact Groups
Prostate (gm)
weights
Serum T (nglml)
Serum
LH
aData that
are
seen
mean
‘GnRH-A *
FSH
0.026
0.023
0.392
0.320
0.363
0.201”
0.246
0.169’
±
±
±
±
±
±
±
±
0.026
0.001
0.002
0.047
0.035
0.03
0.042
0.040
0.019
0.25
0.25
0.8”
0.035
Since
3.9
1.1”
1.4
1.4
3.3
0.7”
1.5
±
±
±
±
±
±
±
0.7
0.1
0.4
0.1
0.5
0.1
0.1
0.1
0.50
0.68”
11.2
1.12”
1.20
0.49”
1.32
0.95”
0.64
0.80”
±
±
±
±
±
±
±
±
±
±
0.02
0.02
0.04
0.10
0.02
0.05
0.02
0.04
0.03
is different
in the
castrated
animals
SEM,
n=10
0.03
in each
because
group.
of absence saline
The
saline
=
in the
did
we treated
compared
not
have for
affect shown 3 days
to
oil vehicle-
thus indicating, effects on pituitary
et a!.,
that LH or
weights
in mean
significantly
and
prostate
different
serum
2). GnRH-A with 22.5-mm
weights
from
treatment T implants,
those of
T
that
in
serum
animals
LH
(Table
response
LH
above that 2). Thus, to normalize
GnRH-A
in
We recognize
Percent
of T
castrated
rats
cannot
that
the
be explained
LH
501000 C
castrated
response
50-
to
than in eugonadal response of the on
the
basis
of
or
similar
selective led to
the T(regard-
qualitatively
that
the
Leydig
similar
selectivity
cell
to
that
suppression an LH response to
of the
function
of of T to
that
of
impairment
induced
rLH
Response
to
by
GnRH-Agonist
these
Treatment
Saline
Data
Co
I -J
in hypogonadal in the LH
qualitatively
0
a.
demonstrate
was
0
0
data
that
rats. In contrast, by ketoconazole
GnRH-A that was intact male rats. tubular
response treatment
Treated
GnRH-A
DISCUSSION
These
from
T dose), was also qualitatively different rats. A preferential lesion of the tubular induced by cryptorchidism led to an
response
castrated synthesis
since the LH rats to GnRH-A
(Table
these castrated animals unlike intact controls, also
to
alone, castrated
not
2).
GnRH-A is different rats. The differences
T-replaced
the
were
of controls
failed to induce elevation of serum LH corresponding saline controls (Table replacement, regardless of dose, failed the
weight
animals.
less of the from intact compartment
of
1986).
castrated + 20-mm T implant groups were somewhat lower than in the intact controls, we inserted 22.5mm T implants in subsequent experiments. This dose of T resulted
T to prostate T-replaced
deficiency replaced
tubular function and demonstrated
ketoconazole used in the no differences in serum
controls, no direct
prostate
of serum
rhythms
p