Reevaluation of the Effect of Follicle-Stimulating Hormone on the ...

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MURPHY weights were recorded at autopsy, between. 1300 and. 1500 h when the animals ... albumin. (Fraction. V)/mlj. Animals. TABLE. 2. Effect of neuraminidase treatment on the ovarian ..... Med. 153:473-475. Chen, Y.-D.I., Shaw, M. J. and.
BIOLOGY

OF REPRODUCTION

26, 422-428

(1982)

Reevaluation

of the Effect of Follicle-Stimulating Hormone on the Steroidogenic Capacity of the Testis: The Effects of Neuraminidase-Treated FSH Preparations W. H. MOGER”2’3 Departments

and

P. R. MURPHY’

of Physiology

and

Obstetrics

and

and

Biophysics’

Gynecology2

Dalbousie University Nova Scotia, Canada

Halifax,

B3H

4H7

ABSTRACT The

ability of FSH treatment to increase the amount of androgen produced by the testis in response to maximum LH stimulation may be an effect of the LH contamination of the FSH preparations. To examine this question, 3 FSH preparations of different potencies and degrees of LH contamination or their neuraminidase-treated derivatives were administered to hypophysectomized immature rats for 5 days. The capacity of the testes to produce androgens in vitro was assessed at the end of the treatment period. Neuraminidase treatment reduces the in vivo activity of ovine and bovine FSH but does not alter the activity of ovine or bovine LH. Neuraminidase treatment of one FSH preparation (NIH-bFSH-B1) did not reduce the ability of this FSH preparation to increase the response of the testisto LH stimulation in vitro. This suggests that the considerable neuraminidase

LH

contamination treatment

of

the

NIH-bFSH-Bi

may

be

responsible

for

its

effect.

However.

of 2 more highly purified FSH preparations (bFSH-199C and NIH-oFSHSi 3) abolished or greatly reduced the ability of these preparations to increase testicular weight and the response to LH in vitro. It isconcluded that the abilityof highly-purified FSH preparations to increase the amount of androgen produced by the testis is due to the FSH activity and not the contaminating LH.

INTRODUCTION

Administration

concentrations

hormone (FSH) preparations sectomized between the ages reportedly

eta!.,

of various follicle-stimulating

increases

the

to rats hypophyof 20 and 71 days

capacity

of the total

in vivo

stimulation

1976;

Selin

Mahesh, 1977).

and

1981)

(Ode!!

Moger,

and

1977;

or in vitro (Chen

Furthermore,

FSH

Swerdloff, Nazain

and

et a!., 1976,

reportedly

augments

capacity of the mature rabbit testis to secrete testosterone in response to maximum the

LH and

stimulation the serum

ministered (hCG)

human correlates

(Johnson and Ewing, testosterone response chorionic positively

1971), to ad-

gonadotropin with

serum

boys

(Sizonenko

These observations are of particular interest for 2 reasons. First, both serum FSH concentrations and the capacity of the testis to secrete androgens increase during pubertal development in the rat, suggesting a causal relationship (Ode!! et al., 1974; Moger and Armstrong, 1974; Purvis et al., 1978; Moger, 1979). Second, the failure to identify FSH receptors on

mass of testicu!ar tissue to produce androgens in response to maximum !uteinizing hormone (LH)

in cryptorchid

1973).

FSH

Leydig cates

cells (Means and Vaitukaitis, that the effect of FSH on

function

is indirect,

recognized

possibly

target for FSH,

1972)

indicell

Leydig

mediated

via

the

the Sertoli cells.

Recognition that chronic administration of small doses of LH also increases the androgen secretory capacity of the testis (5dm and Moger,

1977;

Zipf

et a!., 1978)

led Purvis and

Hansson (1978) to speculate that the observed effect of FSH was due to LH contamination Accepted December 3, 1981. Received November 5, 1981. 3Correspondence: Dr. William H. Moger, Dept. of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada.

422

of the FSH preparations. Three groups studied this question and arrived at different conclusions. 5dm and Moger (1977) reported that a FSH ination

preparation was

effective

with

very in

little LH

increasing

the

contamandro-

FSH AND

gen

production

TESTICULAR

of the testis

capacity

of

STEROIDOGENESIS

hypo-

preserving

physectomized rats and concluded that FSH was the effective agent. Van Beurden et a!.

rats

increased

isolated

Leydig

cells

response ment

to LH. increases

to

the

secrete

capacity

MATERIALS

in

However, found

FSH

a

similar

preparation

the androgen They

was

response

also reported

FSH-S12

LH

to

FSH tion

et a!.

ineffective

in

of

Leydig

isolated

FSH

which

increasing

with

an

not

affect

the

Neuraminidase

The

re-

tomized

rats

amount arations

of

(1976,

with

doses

of LH equivalent

contamination did not increase

in various androgen

to the

FSH prepproduction

present

tamination of 3 FSH and

with

tion

to

different increase

TABLE

this

FSH

of LH

capacity

of

immature In

the

degrees

the

hypophysectomized ing

reevaluates

LH

con-

addition,

activity

the of

these

rats

of

testes

to

effect of preparations

1. Potencies of gonadotropin

produce destroywhile

FSH

preparations

(Si

of FSH

15.0

NlHbLHB9a