Mating-Induced Luteinizing Hormone Surge and Ovulation in the

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Luteinizing. Hormone. Surge and Ovulation in the Female Camel. (Came/us dromedarius). M. MARIE1 and A. ANOUASSI. Department of Reproduction and A. I..
BIOLOGY

OF

REPRODUCTION

35,

792-798

(1986)

Mating-Induced Luteinizing in the Female Camel M. MARIE1

Hormone (Came/us and

A. ANOUASSI

Department of Reproduction II Institute of Agronomy and B.P. 6202 Rabat-Instituts,

Hassan

Surge and Ovulation dromedarius)

and

A. I. Medicine

Veterinary

Morocco

ABSTRACT Blood

samples

were

collected

mating

hormone matings, five

secretion occurred,

of progesterone). LH levels at the time the levels increased 1 h after mating A

decrease

in LH

was quantified followed by

from

Luteinizing observed

ng/ml).

(LH) were

after

was

observed

four

in plasma a release of

starting

ment with a coitus-induced mechanism of confirm and extend the observations reported

female

of mating and reached 6 h after

ovulation in the

one-humped

camels

by radioimmunoassay using LH, and three by an ovulation ranged from a maximum

mating

and

one-humped

camel

lasting

in the one-humped bactrian camel (Cam

belong

to

ovulators

servations formation females

of ovarian has been by observing

induced

function. established ovaries

been on

considered

the

basis

(Scaramuzzi cat (Johnson

after

mating ovulators

of

Animals

ob-

1980; Wildt et a!., 1980), and ferret (Carroll et a!., the

only

data

on

this

concern

the

9-12

h.

6 h. These

results

are in agree-

dromedarius).

AND

They

METHODS

Sampling

females

(5-8-yr-old)

and

one

vasec-

male

(8-yr-old) were used in this study. The was conducted from 24 January to 10 a period of sexual activity of the male as

indicated by palate evagination and copious secretions from poll glands. The male was housed apart from the females and introduced 1 h each day and observed. When

complete

mating

was restrainted, vein, and blood for 12 h. In two for 8 and 9.5

1973), et al.,

vole (Charlton et a!., 1975), 1985). In camelids, however,

topic

Blood

adult

tomized experiment February,

described the rabbit

et a!., 1972; Dufy-Barbe et a!., and Gay, 1978, 1981; Concannon

and

Four

Lack of corpus luteum either in nonpregnant obtained post-mortem

has been including

for

LH. Of the seven by a subsequent

to

(Shalash and Nawito, 1964; Musa, 1979), or in nonmated females monitored over a long period by rectal palpation (Nawito et a!., 1968; Musa and Abusineina, 1978) and by progesterone monitoring (Elias eta!., 1984). The pattern of luteinizing hormone (LH) secretion in other induced

for

camel (Camelus elus bactrianus).

MATERIAL

has

10 mm

0.7 to 3 ng/ml. When an LH response in 2-3 h (ranging from 2.9 to 19.1

INTRODUCTION The

every antibovine (indicated

collected samples

two-humped

and

camel, Camelus bactrianus (Xu et a!., 1985). The purpose of this paper is to describe the timecourse of LH secretion after mating in C. dromedarius to gain more precise information about the mechanism of ovulation in this species.

then

in were

was

performed,

a catheter was placed samples were collected animals, blood samples h, respectively. Blood

tubes containing refrigerated until

frozen

until

used

sodium plasma for

assay.

the

female

in the jugular every 10 mm were collected samples were citrate. The was separated After

blood

collection was completed, the mated female was isolated for 10 days before a new presentation to the male. During the experimental period, one blood sample was obtained each day from all females for progesterone assay to assess luteal activity. During the same period of the year (February), 6 females (of which 4 were used in the above experiment) not presented to the male were submitted to frequent

Accepted Received ‘Reprint

January July 9, requests.

29,

1986.

blood sampling trol observations

1985.

792

(8 samples/h for 4 h) to provide for LH fluctuations.

con-

LH TABLE

1. Conditions

Animal

of mating,

characteristics

Duration mating

Observation

of LH

release,

of

and

Beginning LH increase

SURGE

IN CAMEL

occurrence

of

793

of ovulation

End of increase

in four

LH

female

camels.

Beginning of LH decrease

End of LH decrease

Subsequent ovulation

yes no yes yes no no no

(mm) I 2 2 3 3 4 4

A B C D E F C

60 80 70 80 100

190 210 240 240 180

300 360 360 380 410

660 680 840 720 640

5

...

...

...

...

8

...

...

...

...

10 10 10 6

5

curve were 89.3% and 4.5%. Parallelism of the standard curve and serial dilutions of came! plasma is illustrated in Figure 1. Regression coefficients of the logit/log

Assays Camel

LH

was

assay procedure (Golter et a!.,

quantified

by

described for 1973). Nonspecific

total count, absolute relative binding for

binding extreme

the

heterologous

measuring binding

(est) (est)

bovine LH was 4.5% of

for BO was 3 8.4%, and points of the standard

(dose) linear relations spectively. Sensitivity (0.25

ng/ml

coefficients

of plasma). of

12.5

variation

25

were of the

-0.98 assay

The

intraassay

for

and was

-0.97, re25 pg/tube

and

a plasma

interassay

sample

50

100 I

p1

plasma

2

1’

0’ 0

-1’ 4J

0 -J

-2’

-3’ ng U----

0.05 FIG.

1. Binding

inhibition

-U--

-

0.1 of LH ovine

-

0.25 standard

(t=oLH

0.5 24)

and

of serial

-.

I

U

1

2.5

5

dilutions

of camel

plasma

(0).

0LH U

10

con-

794

MARIE

AND

ANOUASSI

A 21

II

2

i

t

3

I

s

$

I

is

ii

12

D 21

II

2

1

2

3

4

1

I

i

I

I

ii

il

12

LH

FIG.

2. Individual

taming (n=7)

13.1 and

observations

ng/ml

9.7%

Progesterone

of

of

LH

LH

evolution

were

after

SURGE

mating.

respectively

Vertical

7.1%

was

axis”LH

(ng/mI),

(mean: 180

(n=5). assayed

by the

method

described

795

IN CAMEL

horizontal

1 h to

were mm). from level.

240

18

axis”time

mi.

mm

(hours

after

Maxima!

after

mating

mating).

values (mean:

were

obtained

3 h 30

mm)

and

maintained for 110 to 230 mm (mean: 2 h 30 During this period, the mean LH values ranged 2.94 to 19.1 ng/m!, or 1.8 to 8.7 times the basal LH values began to decline 300 to 410 mm

for plasma by Marie et al. (1984); the only modification was the use of 2.5 ml of diethyl ether for plasma extraction. Sensitivity of the assay was 0.14 ng/ml. For plasma samples containing respectively 0.47 ng/ml and 3.20 ng/ml, coefficients of variation were 16.0% and 4.0%, respectively, for intraassay, and

after mating (mean: 6 h) and returned to baseline levels 5 h 45 mm later. The decrease of LII in terms of logarithm of the values was in linear relation with

14.4%

time,

and

5.0%

for

interassay.

and

its rate

was

less

than

that

of the

postmating

increase. RESU

Data

are

summarized

time courses of LH in Figure 2. Matings

LTS

in secretion lasted

Table

significantly

cases

(A to between

E), 60

the and

in

individual

patterns are represented from 5 to 10 mm, and

a!! cases, intromission was servations, LII levels remained after mating. This corresponds from 0.68 to 2.95 ng/ml. In five

1 and

in

completed. For all obquite stable at least 1 h to basal levels ranging basal 100

LH mm

level after

increased mating

Control Figure

periodic period; tically ng/ml, 2.

data from 3. These elevations each peak

of LH, is followed

constant, basal which is similar

Moreover,

observed demonstrates patterns

nonmated patterns

LII during that

A to

generally 4 by a return

in the 4-h to a prac-

level, ranging from 0.7 to 2 to patterns F and G in Figure

values the

females are presented are characterized by

are

consistent

first hour fluctuations

E in Figure

2 were

with

levels

after mating. This observed in the not

caused

by

stress

796

MARIE

due to an animal’s struggling sampling, nor from varmatmons in absence of matmng. In three

cases

(A, C, D),

by an ovulation, functional corpus (>0.8 mating of

the

LH

demonstrated luteum. High

ng/ml) were detected to 10 to 11 days after

6.1,

3.8

and

days after progesterone

2.4

ng/ml

mating, secretion

observations four other (