• 沒有找到結果。

The mode of action of carp gonadotropin on the stimulation of androgen production by carp testis in vitro

N/A
N/A
Protected

Academic year: 2021

Share "The mode of action of carp gonadotropin on the stimulation of androgen production by carp testis in vitro"

Copied!
7
0
0

加載中.... (立即查看全文)

全文

(1)

The Mode of Action of Carp Gonadotropin

on the Stimulation

of

Androgen

Production

by Carp Testis in Vitro

YEA-SHA CHANG AND FORE-LIEN HUANG’

‘Institute of Biological Chemistry, Academia Sinica, P.O. Box 23-106, Taipei, Taiwan

Accepted September 25, 1981

Carp gonadotropin (cGTH) can stimulate carp testis to produce androgen in vitro. This action can be mimicked by dibutyryl CAMP (Bt, CAMP) and prostaglandins (PG). Btp CAMP can enhance the androgen production when submaximal doses of cGTH are used but cannot do so when maximal dose of cGTH is used. PG F,,is more effective than PG E, and E,. Both the inhibitors of RNA and protein synthesis can interfere the stimulatory effect of cGTH. Actinomycin D has 87% while cycloheximide has 100% inhibition. The stimulatory effect of cGTH is much more dependent on de nova protein synthesis than on RNA synthesis. In addition, steroidogenesis inhibitors, glutethemide, metyrapone, and spirocyanoketone, can also inhibit the stimulatory effect of cGTH on androgen production.

Luteinizing

hormone (LH) can stimulate

testis to produce androgen in higher verte-

brates either in viva or in vitro (Cigorraga et

al., 1978; Cooke et al., 1975, 1979; Dufau et

al., 1971; Hafiez et al., 1972; Maung and

Follett,

1977; Mendelson

et al., 1975; Mul-

ler, 1977). The available evidences indicate

that cyclic adenosine 3’S’-monophosphate

(CAMP) is an intracellular

messenger of LH

on androgen production

(Cigorraga et al.,

1978; Cooke et al., 1979; Dufau et al., 1971;

Rommertz

et al., 1974). The stimulatory

effect of LH on androgen production

is de-

pendent on de wvo protein synthesis since

ribonucleic

acid (RNA) and protein synthe-

sis inhibitors

can inhibit the stimulatory

ef-

fect of LH (Cigorraga et al., 1978; Cooke et

al., 1975, 1979; Dufau et al., 1974; Mendel-

son et al., 1975; Moyle et al., 1971; Shin and

Sato, 1971). The effect of LH on androgen

production is mainly due to its promotion

of

the conversion of cholesterol

to pregneno-

lone (Bakker

et al., 1978; Cigorraga

et

al., 1978; Hall and Eik-Nes,

1964; Hall

and Young, 1968; Purvis et al., 1973; van

der Vusse et al., 1975).

Our previous results indicated

that fish

r To whom all correspondence should be sent.

gonadotropin

(GTH)

can stimulate

male

carp to produce androgen either in vivo

(Jean, 1980) or in vitro (Huang and Chang,

1980). The mode of action of fish GTH has

seldom been investigated.

Only a few lines

of evidence indicate that fish GTH can en-

hance the fish gonad to produce

CAMP

(Fontaine et al., 1970; Fontaine-Bertrand

et

al., 1978; Idler et al., 1975). In this study

attempts are made to investigate the mode

of action

of carp GTH

(cGTH)

on the

stimulation

of androgen production by carp

testis in vitro by the following approaches:

(1) whether dibutyryl

CAMP

(Btz CAMP)

and prostaglandins

(PG) can mimic the ac-

tion of cGTH, (2) whether the stimulatory

effect of cGTH

is dependent

on de novo

RNA and protein synthesis, and (3) wheth-

er the various

kinds of steroidogenesis

inhibitors

effective in mammalian

systems

can inhibit the stimulatory

effect of cGTH

on androgen production.

MATERIALS AND METHODS

Chemicals. Actinomycin D, bovine serum albumin (BSA), chick ovomucoid, cycloheximide, Bt, CAMP, PC E,, E, and F,,, and steroids were purchased from Sigma, St. Louis, Missouri. [3H]Testosterone was from the Radiochemical Center, Amersham, England. Ether was from Wako Pure Chemical Industries, 147

0016-6480/82/100147-07$01.00/O Copyright @ 1982 by Academic Press, Inc.

(2)

Japan. Glutethemide (3-phenyl-3-ethyl-2,6-dioxo- piperidin) and metyrapone (2-methyl-1,2-di-3-pyridyl- I-propanone) were the kind gifts from Dr. J . Y. Chang, Ciba Company, Basel. Spirocyanoketone (2a-cyano- 4,4-dimethyl-20-spirox-5-en-3-one) was the kind gift from Dr. G. H. Rasmusson, Merck, Sharp and Dohme Research Laboratories, New Jersey. The cGTH used in this study was prepared as previously described (Huang and Chang, 1980). For assay, actinomycin D, cycloheximide, BtZ CAMP, and glutethemide were dis- solved in incubation medium (see below) whereas metyrapone, PGs, and spirocyanoketone were dis- solved in absolute alcohol.

evaluation of the stimulatory effect of Btz CAMP and PGs, the amount of androgen produced was intrapo- lated into the dose-response curve of cGTH to get the equivalent amount of cGTH by which similar amount of androgen was produced. For evaluation of the in- hibitory effect of inhibitor on the action of cGTH, carp testis was incubated with 0.8 ,ug cGTH in the absence or presence of inhibitor. Similar intrapolation as that mentioned above was also made to get the equivalent amount of cGTH (in the unit of pg) in the presence of inhibitor and denoted as eq-CGTH,,,. The percentage of inhibition was calculated as (1 - eq-cGTI-&,,,/O.l) x 100%.

Androgen production by carp testis in vitro. The method for the assay of the effect of cGTH and other substances on androgen production by carp testis in vitro was the same as previously described (Huang and Chang, 1980). Mature male carps (Cyprinus carpio L.) were collected during breeding season (December to March). Their body weights and gonadosomatic in- dexes (testis wt/body wt X 100) were from 300 to 500 g and 15 to 25, respectively. Testes from 3 to 4 fishes were pooled and finely chopped. The chopped tissues were washed with washing medium (8/9 strength of Krebs-Ringer bicarbonate buffer, pH 7.4, sup- plemented with 0.1% BSA and 0.03% chick ovo- mucoid) until no whitish material was left in the supematant. The washed tissues were preincubated in washing medium under 95% O,-5% CO, for 15 min and then centrifuged at SOOOg for 10 min to remove excess medium. For assay, 200 mg of preincubated tissue were suspended in 2 ml of incubation medium (same as washing medium except 1 mM theophylline was supplemented). An aliquot containing a given quantity of cGTH or other substances was also added to the incubation medium. For those alcohol-soluble substances, a given quantity in 10 ~1 of absolute al- cohol was added. Vehicle alone was served as control. In this study, samples for all assays in a set of experi- ment (i.e., all assays included in a given figure) were derived from a same batch of tissue preparation unless otherwise indicated. Triplicate determinations were made for each assay.

RESULTS

The Stimulatory

Effect of cGTH

The cGTH

can stimulate

carp testis to

produce androgen in vitro. The range of

dose-response

curve is from 0.1 to 1.6 pug,

and in certain cases to 3.2 pg (Figs. 1 and

3). The time course of androgen production

under the stimulation

of cGTH is shown in

Fig. 4. The rate of androgen production

is

slower at the earlier than at the later period

of incubation.

The Effect of Bt, CAMP

The Btl CAMP can stimulate

carp testis

to produce androgen in vitro. The effect of

1, 5, 10, and 20 rnkf Bt, CAMP are equiva-

lent to 0.10, 0.20, 0.64, and 0.90 pg of

Incubation was performed at 25” under 95% O,-5% CO, with slow constant shaking for 4 hr and termi- nated by centrifugation (5OOOg for 10 min). The super- natant was extracted with ether and then the androgen content was measured by radioimmunoassay as previ- ously described. The antiserum used was raised against testosterone 17-hemisuccinate BSA conjugate. By using testosterone as reference (lOO%), the antise- rum had 153% and 6% cross-reactivity toward androstenedione and 1 I-ketotestosterone, respec-

tively.

O-El

DOSE OF GTH Cvg)

Evaluation of the effect of Btz CAMP, PGs, and in- hibitors on androgen production. The dose-response curve of the stimulatory effect of cGTH on carp testis

to produce androgen is nonlinear (see Results). For triplicate determinations.

FIG. 1. The dose-response curve of cGTH on the

stimulation of androgen production by carp testis in

vitro. Each point and line indicate the mean ? SD of

(3)

cGTH

on the aspect of the stimulation

of

androgen production

(Fig. 2).

When Btz CAMP and cGTH

are added

together to the incubation

medium,

the ef-

fect is always higher than that when either

of them is present alone in the incubation

medium.

These results indicate

that Btp

CAMP can express its effect in the presence

of cGTH. However, the extent of the effect

of Bt, CAMP is dependent on the concen-

tration of coexisting

cGTH.

At the lower

concentration

of cGTH

(0.1-0.4

pg), the

effect of Btz CAMP and cGTH are additive.

When the concentration

of cGTH

is in-

creased up to 0.8 pg and more, the effect of

Bt, CAMP becomes progressively

less and

finally

disappears

(Fig. 3). Under

the

stimulation

of maximal

dose of cGTH,

the

amount of androgen produced is the same

whether Bt, CAMP is present or not. Thus

the effect of Btz CAMP

is completely

masked by maximal

dose of cGTH.

The Effect of PG

As shown in Fig. 2, PG El, Ez, and F,,

have stimulatory

effect on androgen pro-

duction. At the concentration

of 20 pg/ml,

200

1

GTH Bt2 CAMP E, E; F

FIG. 2. The stimulatory effects of Btt CAMP, PG El,

E$, and F,, on androgen production by carp testis in vitro, and the inhibitory effects of actinomycin D (AD) and cycloheximide (CH) on Btz CAMP. The doses of cGTH, BtZ CAMP, and PGs are shown in the figure whereas those of actinomycin D and cycloheximide are 0.1 m&f. Each bar and line indicate the mean and standard deviation of triplicate determinations.

0

.l .2 4 0 1.6 32

DOSE OF GTH Ivg/TUBE)

FIG. 3. The effects of BtZ CAMP and cGTH on the

stimulation of androgen production by carp testis in vitro. The doses of cGTH used are shown in the figure whereas that of Bt, CAMP is 10 mkf. 0, cGTH is pres- ent alone; 0, cGTH and Bt2 CAMP are coexisting. Each point and line indicate the mean 2 SD of tripli- cate determinations.

the effect of PG El, EP, and Fzo, are equiva-

lent to 0.33, 0.62, and 0.73 pg of cGTH,

respectively.

The Effect of Actinomycin

D

and Cycloheximide

When the concentration

of actinomycin

D is kept at 0.01 mM, the stimulatory

effect

of cGTH on androgen production

is inhib-

ited by 87% (Fig. 6). The inhibitory

effect of

actinomycin

D becomes progressively

less

marked as the interval between the addition

of cGTH

and actinomycin

D is increased.

When the time interval is increased up to 3

hr, actinomycin

D has no more effect (Fig.

4). In addition,

actinomycin

D can also in-

hibit the stimulatory

effect of Bt, CAMP on

androgen production

(Fig. 2).

When added simultaneously

with cGTH,

0.1 mM of cycloheximide

can completely

abolish

the stimulatory

effect of cGTH.

Furthermore,

the amount of androgen pro-

duced by the tissue in the coexistence

of

cycloheximide

and cGTH

is even lower

(4)

150

CHANGANDHUANG

FIG. 4. The effect of actinomycin D added at vari- ous time intervals of incubation on the androgen pro- duction by carp testis in vitro under the stimulation of cGTH. The doses used for cGTH and actinomycin D are 0.8 @g and 0.01 mA4, respectively. 0 and lines, means rfr SD of triplicate determinations of control; 0 and lines, means and SD of triplicate determinations in which actinomycin D is added at various time intervals and incubation is allowed to continue up to 4 hr. **P < 0.05 and *P < 0.10 versus control of 4-hr incubation, respectively.

than that produced

by the control tissue

(significant at 10% but not at 5% level) (Fig.

6). In contrast with actinomycin

D, the in-

hibitory

effect of cycloheximide

on the

cGTH

does not become lessened as the

time interval between the addition of cGTH

and cycloheximide

is increased. Whenever

the cycloheximide

is added, the effect of

cGTH is abolished (Fig. 5). The statistical

analysis

indicates

that the amount

of

androgen produced by control group within

a given time interval is not different signifi-

cantly from that produced by the group in

which cycloheximide

is added at a given

time interval and incubation

is allowed to

continue for another time interval up to 4

hr. In addition,

cycloheximide

can also

abolish the stimulatory

effect of Bt, CAMP

on androgen production

(Fig. 2).

The Effect of Steroidogenesis

Inhibitors

As shown in Fig. 6, the three types of

inhibitors

effective in mammalian

systems

are also effective in carp testis. At the con-

centration of 2, 2, and 0.02 mM, glutethe-

mide, metyrapone,

and spirocyanoketone

have 95.8, 84.0, and 73.0% of inhibition

on the stimulatory

effect of cGTH

on an-

drogen production,

respectively.

DISCUSSION

The stimulation

of testis to produce

androgen is one of the main effects of LH in

higher vertebrates

(Cigorraga et al., 1978;

Cooke et al., 1979; Dufau et al., 1971;

Hafiez et al., 1972; Maung

and Follett,

1977; Mendelson et al., 1975; Mullet-, 1977).

The testis or its dispersed Leydig cells has

been used by many investigators as a model

system to probe the mode of action of LH

on steroidogenesis

(Bakker

et al., 1978;

Cigorraga et al., 1978; Cooke et al., 1975,

1979; Hall and Eik-Nes,

1964; Hall and

Young, 1968; Mendelson

et al., 1975; Pur-

vis et al., 1973; van der Vusse et al., 1975).

Recently,

we have demonstrated

that fish

GTH can stimulate

carp testis to produce

androgen in vitro (Huang and Chang, 1980),

therefore attempts have been made to use

this newly developed system as a model to

investigate the mode of action of fish GTH.

The action of LH on steroidogenesis

is

proposed to be via the CAMP as cellular

TlME’OF INC:t3ATION3,HR, L FIG. 5. The effect of cycloheximide added at vari- ous time intervals of incubation on the androgen pro- duction by carp testis in vitro under the stimulation of cGTH. The doses used for cGTH and cycloheximide are 0.8 pg and 0.1 mM, respectively. 0 and lines, means + SD deviations of triplicate determinations of control; 0 and lines, means and SD of triplicate de- terminations in which cycloheximide is added at vari- ous time intervals and incubation is allowed to con- tinue up to 4 hr. The same batch of tissue is used for assays of Figs. 4 and 5.

(5)

GTH AD CH G T Ml? SC FIG. 6. The effects of inhibitors of RNA and protein synthesis, and steroidogenesis on androgen production by carp testis in vitro under the stimulation of cGTH. The doses of cGTH used for dose-response curve are shown inside the bar whereas those for assay of the inhibitory effect of various inhibitors are 0.8 pg. The doses of inhibitors used are as follows: actinomycin D (AD), 0.01 mM; cycloheximide (CH), 0.1 mM; glutethemide (GT), 2 mM; metyrapone (MR), 2 n&f; spirocyanoketone (SC), 0.02 mM. Each bar and line indicate the mean and SD of triplicate determinations.

messenger (Cigorraga et al., 1978; Cooke

et

al., 1979; Dufau et al., 1971; Rommertz

et

al., 1974). It is also demonstrated

that Btz

CAMP can stimulate

androgen production

by carp testis in the present study. This

finding seems to suggest that the action of

cGTH

may also be through CAMP as the

second messenger.

The effects of PG El, Ez, and FPa on

steroidogenesis

are variable depending

on

the type of steroid,

type of tissue and

species of animal

investigated

(Behrman

and Hichens,

1976; Erickson

and Ryan,

1975, 1976; Labhsetwar,

1974; Lindner

et

al., 1974; McNatty

et al., 1975; Neal et al.,

1975; Patwardhan and Lanthier,

1977). The

present results provide additional

evidence

that PG El, Ez, and FZa can also stimulate

carp testis to produce androgen. Whether

the stimulation

of PGs on androgen pro-

duction in carp testis is through the stimu-

lation

of CAMP

formation

as found in

mouse ovary (Kuehl et al., 1970) remains to

be elucidated.

The present

results

indicate

that the

stimulatory

effect of cGTH

on androgen

production

by carp testis is dependent

on

de nova RNA and protein

synthesis be-

cause actinomycin

D and cycloheximide

can inhibit or abolish this effect. A similar

situation

is also found in the mammalian

system (Cigorragaet

al., 1978; Cooke et at.,

1979; Dufau et al., 1974; Mendelson

et al.,

1975; Moyle et al., 1971; Shin and Sato,

1971). In rat the dependence of stimulatory

effect of LH on de nova protein synthesis is

more than that on de lzovo RNA synthesis.

The inhibitory

effect of actinomycin

D be-

comes progressively

less marked

as the

time interval between the addition

of LH

and actinomycin

D is extended and finally

disappears if the interval is increased up to

2.5 hr. On the other hand, even when cy-

cloheximide

is added 2.5 hr following LH,

it can still affect the testosterone production

although

the extent is lessened relatively

(Mendelson

et al., 1975). In carp, the de-

pendence of stimulatory

effect of cGTH on

de 110~0 RNA synthesis becomes progres-

sively less marked and finally becomes in-

dependent if the time interval between the

addition

of cGTH

and actinomycin

D is

long enough. On the contrary, the stimula-

tory effect of cGTH

is stringently

depen-

dent on the de nova protein

synthesis.

Cycloheximide

can abolish

the effect of

cGTH whenever it is added to the incuba-

tion medium.

Our data suggest that cGTH

can induce the synthesis of regulatory pro-

teins including enzymes for steroidogenesis

by which androgen production

in carp testis

is stimulated.

These regulatory proteins are

very labile, therefore the stimulatory

effect

of cGTH is dependent on their continuous

synthesis. The finding that the inhibitory

effect of actinomycin

D becomes

less

marked or even totally

insignificant

may

suggest that the messenger RNAs for these

regulatory proteins are comparatively

more

stable and can be accumulated.

Other pos-

sibilities

are not excluded,

such as the

presence of lag period for actinomycin

D to

penetrate into the testicular tissue.

(6)

152

CHANG AND HUANG

The present results indicate that gluteth-

emide, an inhibitor

of cholesterol

20tr-hy-

droxylase

(Kahnt

and Neher,

1966), me-

tyrapone,

an inhibitor

of cytochrome

P-

450-linked

reactions

(Satre and Vignais,

1974) and spirocyanoketone,

an inhibitor

of

C19- and C2,-3P-hydroxysteroid

dehydroge-

nase (Goldman and Sheth, 1973) can inhibit

the stimulatory

effect of cGTH on androgen

production

by carp testis. The fact that the

stimulatory

effect of cGTH can be almost

completely

abolished by glutethemide

indi-

cates that the conversion of cholesterol

to

pregnenolone

is necessary for expression of

cGTH

effect on androgen synthesis. The

regulatory role of LH on the conversion of

cholesterol

to pregnenolone

has been well

demonstrated

in mammals

(Bakker et al.,

1978; Cigorraga et al., 1978; Hall and Eik-

Nes, 1964; Hall and Young, 1968; Purvis

et

al., 1973; van der Vusse et al., 1975).

Whether

the conversion

of cholesterol

to

pregnenolone

in carp testis is also under the

control of cGTH is currently being investi-

gated in this laboratory.

ACKNOWLEDGMENTS

The authors express their sincere appreciation to Professor T. B. Lo, Dean of Science College, National Taiwan University, for his encouragement and advice. This work was financially supported by the National Science Council of the Republic of China (NSC-70- 0203-BOOl-03)

REFERENCES

Bakker, C. P., van der Plan-van Winsen, M. P. I., and van der Molen, J. J. (1978). Effect of cytosol frac- tions from lutropin-stimulated rat testes on preg- nenolone production by mitochondria from nor- mal rat testes. Biochim. Biophys. Acta 543, 235-242.

Behrman, H. R., and Hichens, M. (1976). Regulation of ovarian steroid secretion. Prostnglandins 12, 83-95.

Cigorraga, S. R., Dufau, M. L., and Catt, K. J. (1978). Regulation of luteinizing hormone receptors and steroidogenesis in gonadotropin-desensitized Leydig ceils. 1. Biol. Ciwm. 253, 4297-4304. Cooke, B. A., Janszen, F. H. A., Clotscher, W. F.,

and van der Molen, H. J. (1975). Effect of protein-synthesis inhibitors on testosterone pro- duction in rat testis interstitial tissue and Leydig- cell preparation. Biochem. J. 150, 413-418. Cooke, B. A., Lindh, L. M., Janszen, F. H. A., van

Driel, M. J. A., Bakker, C. P., van der Plank, M. P. I., and van der Molen, H. J. (1979). A Leydig cell tumor: A model for the study of lutro- pin action. Biochim. Biophys. Acfa 583,320-331. Dufau, M. L., Catt, K. J., and Tsuruhara, T. (1971).

Gonadotropin stimulation of testosterone produc- tion by the rat testis in vitro. B&him. Bioph.ys. Acta 252, 574-579.

Dufau, M. L., Mendelson, C., and Catt, K. J. (1974). A highly sensitive in vitro bioassay for luteinizing hormone and chorionic gonadotropin: Testoster- one production by dispersed Leydig cells. J. C/in. Endocrinol. Meta. 39, 610-613.

Erickson, G. F., and Ryan, K. J. (1975). Effect of LI-FFSH, dibutyryl cyclic AMP and prostaglan- dins on the productions of estrogens by rabbit granulosa cells in vitro. Endocrinology 97, 108-113.

Erickson, G. F., and Ryan, K. J. (1976). Stimulation of testosterone production in isolated rabbit thecal tissue by LIVFSH, dibutyryl cyclic AMP, PG F,, and PG EP. Endocrinology 99,452-458.

Fontaine, Y. A., Burzawa-Gerard, E., and Delerue-Le Belle, N. (1970). Stimulation hormonale de l’acti- vite adenyl cyclasique de I’ovaire d’un poisson teleosteen, le cyprin (Carassius auratus L.). C.R. Acad. Sci. Paris Ser. D 271, 780-783.

Fontaine-Bertrand, E., Salmon, C., and Fontaine, Y. A. (1978). Effect d’hormones gonadotropes, in vitro, sur la concentration de I’adenosine mono- phosphate cyclique dans l’ovaire de l’anguille (Anguilla anguilla L.). Ann. Biol. Anim. Biochim. Biophys. 18, 805-811.

Goldman, A. S., and Sheth, K. (1973). Inhibitors of human placental C,,- and C,,-3P-hydroxysteroid dehydrogenases. Biochim. Biophys. Acta 315, 233-249.

HaEez, A. A., Lloyd, E. W., and Bartke, A. (1972). The role of prolactin in the regulation of testis function: The effects of prolactin and luteinizing hormone on the plasma levels of testosterone and androstenedione in hypophysectomized rat. J. Endocrinol. 52, 327-332.

Hall, P. F., and Eik-Nes, K. B. (1964). The effect of interstitial cell-stimulating hormone on the pro- duction of pregnenolone by rabbit testis in the presence of an inhibitor of 17a-hydroxylase. Biochim. Biophys. Acta 86,604-609.

Hall, P. F., and Young, D. G. (1968). Site of action of trophic hormones upon the biosynthetic pathways to steroid hormones. Endocrinology 82,559-568. Huang, F. L., and Chang, Y. S. (1980). The gonado-

tropic stimulation of androgen production on carp testis in vitro. Proc. Nat. Sci. Count. ROC 4, 392-400.

Idler, D. R., Hwang, S. J., and Basar, L. S. (1975). Fish gonadotropin(s). I. Bioassay of salmon go- nadotropin(s) in vitro with immature trout gonads. Endocrinol. Res. Commun. 2, 199213.

(7)

Jean, W. C. (1980). “The Effect of Pike Eel Gonado- tropin on the Content of Carp Plasma Androgen.” Masters thesis. Department of Zoology, National Taiwan Univ.

Kahnt, F. W., and Neher, R. (1966). Uber die adrenale steroid-biosynthese in vitro. III. Selektive hem- mung der nebennierenrinden-funktion. Helv. Chim. Acta 49, 725-732.

Kuehl, F. A. Jr., Humes, J. L., Tamoff, J., Cirillo, V. J., and Ham, E. A. (1970). Prostaglandin re- ceptor site: Evidence for an essential role in the action of luteinizing hormone. Science 169, 883-886.

Labhsetwar, A. P. (1974). Prostaglandins and the re- productive cycle. Fed. Proc. 33, 61-77.

Lindner, H. R., Tsafrii, A., Lieberman, H. E., Zor, U., Koch, Y., Bauminger, S., and Bamea, A. (1974). Gonadotropic action on cultured GrafIian follicles: Induction of maturation division of the mammalian oocytes and differentiation of the luteal cell. Rec. Prog. Horm. Res. 30, 79-138. Maung, Z. W., and Follett, B. K. (1977). Effects of

chicken and ovine luteinizing hormone on androgen release and cyclic AMP production by isolated cells from the quail testis. Gen. Camp.

Endocrinol. 33, 242-253.

McNatty, K. P., Henderson, K. M., and Sawers, R. S. (1975). Effects of prostaglandin Ftr, and E, on the production of progesterone by human granulosa cells in tissue culture. J. Endocrinol.

67, 231-240.

Mendelson, C., Dufau, M., and Catt, K. J. (1975). De- pendence of gonadotropins-induced steroidogen- esis upon RNA and protein synthesis in the inter- stitial cells of the rat testis. Biochim. Biophys. Acta 411, 222-230.

Moyle, W. R., Moudgal, N. R., and Creep, R. 0. (1971). Cessation of steroidogenesis in Leydig cell tumors after removal of luteinizing hormone and

adenosine cyclic 3’,5’-monophosphate. J. Biol. Chem. 246, 4978-4982.

Muller, C. H. (1977). Plasma 5dihydrotestosterone and testosterone in the bullfrog, Rana cates- beiana: Stimulation by bullfrog LH. Gen. Camp. Endocrinol. 33, 122- 132.

Neal, P., Baker, T. G., McNatty, K. P., and Scaramuzzi, R. J. (1975). Influence of prostaglan- dins and human chorionic gonadotropin on pro- gesterone concentration in organ culture. J. En- docrinol. 65, 19-25.

Patwardhan, U. V., and Lanthier, A. (1977). Effect of prostaglandin on the in vitro biosynthesis of es- trone, estradiol and progesterone by rabbit ovar- ian follicles. J. Steroid Biochem. 8, 777-780.

Purvis, L. J., Canick, J. A., Rosenbaum, J. H., Hologgitas, J., and Latif, S. A. (1973). Control of cytochrome P-450 in rat testis mitochondria by human chorionic gonadotropin. Arch. Biochem. Biophys. 159, 32-38.

Rommertz, F. F. G., Cooke, B. A., and van der Molen, J. J. (1974). The role of cyclic AMP in the regulation of steroid biosynthesis in testis tissue.

J. Steroid Biochem. 5, 279-285.

Satre, M., and Vignais, P. V. (1974). Steroid llp- hydroxylation in beef adrenal cortex mitochon- dria. Binding affinity and capacity for specific %-steroids and for 3H-metyrapol, an inhibitor of lip-hydroxylation. Biochemistry 13, 2201-2209. Shin, S., and Sato, G. H. (1971). Inhibition by ac-

tinomycin D, cycloheximide and puromycin of steroid synthesis induced by cyclic AMP in inter- stitial cells. Biochem. Biophys. Res. Commun. 45,

501-507.

Van der Vusse, G. J., Kalkman, M. L., and van der Molen, J. J. (1975). Endogenous steroid produc- tion in cellular and subcellular fractions of rat tes- tis after prolonged treatment with gonadotropins.

數據

FIG.  1.  The  dose-response  curve  of  cGTH  on  the  stimulation  of  androgen  production  by  carp  testis  in  vitro
FIG.  2.  The  stimulatory  effects of Btt  CAMP,  PG  El,
FIG.  4.  The  effect  of  actinomycin  D  added  at  vari-  ous  time  intervals  of incubation  on  the  androgen  pro-  duction  by carp  testis  in  vitro  under  the  stimulation  of  cGTH
FIG. 6.  The  effects of inhibitors  of RNA  and  protein  synthesis,  and  steroidogenesis  on  androgen  production  by carp  testis  in  vitro  under  the  stimulation  of cGTH

參考文獻

相關文件

好了既然 Z[x] 中的 ideal 不一定是 principle ideal 那麼我們就不能學 Proposition 7.2.11 的方法得到 Z[x] 中的 irreducible element 就是 prime element 了..

volume suppressed mass: (TeV) 2 /M P ∼ 10 −4 eV → mm range can be experimentally tested for any number of extra dimensions - Light U(1) gauge bosons: no derivative couplings. =&gt;

For pedagogical purposes, let us start consideration from a simple one-dimensional (1D) system, where electrons are confined to a chain parallel to the x axis. As it is well known

The observed small neutrino masses strongly suggest the presence of super heavy Majorana neutrinos N. Out-of-thermal equilibrium processes may be easily realized around the

incapable to extract any quantities from QCD, nor to tackle the most interesting physics, namely, the spontaneously chiral symmetry breaking and the color confinement.. 

(1) Determine a hypersurface on which matching condition is given.. (2) Determine a

• Formation of massive primordial stars as origin of objects in the early universe. • Supernova explosions might be visible to the most

• elearning pilot scheme (Four True Light Schools): WIFI construction, iPad procurement, elearning school visit and teacher training, English starts the elearning lesson.. 2012 •