안드로젠이 수컷 흰쥐 음부대퇴신경 운동핵에 미치는 영향에 관한 형태계측학적 연구

Abstract

[한글]

고환의 하강과정에 고환도대와 안드로젠이 관여함은 잘 알려진 사실이다. 고환도대를 지배하는 것으로 믿어지는 음부대퇴신경을 신생기에 절단하면 고환올림근이 위축되고 정상적인 고환하강이 이루어지지 않으므로, 고환의 하강과정에 있어서 음부대퇴신경과 안드

로젠온 서로 연관이 있을 것으로 보여진다. 한편 최근에 음부대퇴신경의 척수 운동핵이 성별 차이를 보이는 것으로 관찰되었으며, 성별차이를 보이는 다른 운동핵들은 안드로젠

에 의하여 그 형태가 변화하므로 음부대퇴신경 운동핵의 형태도 안드로젠의 영향을 받을 가능성이 있으나 지금까지는 이에 대한 보고가 없다. 그러므로 고환하강 기전의 영향요소로서의 음부대퇴신경 운동핵과 안드로젠과의 관계를 밝히고자 이 연구를 시행하였다.

흰쥐에서 역행 추적법을 이용하여 정상 수컷과 암컷의 음부대퇴신경 운동핵을 관찰하고, 생후 24시간내에 한쪽 고환을 제거하여 고환 제거쪽 음부대퇴신경 운동핵의 변화를 반대쪽과 비교하였으며, 생후 24시간내에 양쪽 고환을 제거하여 안드로젠의 결핍을 유발하고 일부에서는 다시 안드로젠을 보상한 후 음부대퇴신경 운동핵의 변화를 대조군과 비교하여 다음과 같은 결과를 얻었다.

1. 수컷과 암컷의 음부대퇴신경 운동핵의 위치는 비슷하였으며, 신경세포의 수와 크기는 수컷이 암컷보다 컸다.

2. 신생기에 한쪽 고환을 제거한 경우, 고환올림근은 고환 제거쪽이 현저하게 위축되었으나 음부대퇴신경 운동핵의 세포수는 고환 제거쪽과 반대쪽이 차이가 없었으며 세포체 크기는 고환 제거쪽이 더 컸다.

3. 신생기에 양쪽 고환을 제거한 경우, 고환올림근이 현저하게 위축되었으며 음부대퇴신경 운동핵의 세포 수와 세포체 크기의 감소가 관찰되었다.

4. 신생기에 양쪽 고환을 제거하고 안드로젠으로 보상하면, 고환올림근은 보상에 관계없이 현저하게 위축되었으나 세포수와 세포체 크기의 감소는 나타나지 않았다. 그리고 음부대퇴신경 운동핵에 대한 효과는 testosterone보다 dihydrotestosterone으로 보상한 경우에 더욱 뚜렷하였다.

이상의 결과로서 음부대퇴신경 운동핵이 성별 차이를 보이는 것을 확인하였고, 안드로젠은 신생기에 음부대퇴신경 운동핵의 신경세포 수와 세포체 크기에 직접적인 영향을 주는 것으로 판단된다. 그러므로 흰쥐에서 고환이 하강하는데 안드로젠은 음부대퇴신경 운동핵에 영향을 주고, 이 음부대퇴신경은 고환이 하강하는데 영향을 미치는 일련의 과정이 발생하는 것으로 생각되며, 이러한 과정에 있어서 안드로젠중 특히 dihydrotestosterone의 영향이 더 뚜렷한 것으로 보여진다.

Effect of Neonatal Androgens on Genitofemoral Motonucleus in the Male Rat

Sang Won Han

Department of Medical Science The Graduate School, Yonsei University

(Directed by Professor Seung Kang Choi, M.D., Ph.D.)

It is generally accepted that androgens and gubernaculum testis play a part in

testicular descent. In neonatal rat, division of the genitofemoral descent of

testis caused atrophy of cremasteric muscle and diturbed normal descent of testis.

The gubernaculum testis is regarded to be richly innervated by the genitofemoral

nerve. So the genitofemoral nerve seems to be closely related to the androgens

during testicular descent. Recently it is observed that the genitofemoral

motonucleus of rat showed sexual difference. As the other motonucleus showing

sexual difference the genitofemoral motonucleus is might be altered morphologically

by manipulation of neonatal androgens. Therefore This experiment was designed to

illustrate morphologically the relation between the androgens and the genitofemoral

motonucleus using retrograde tracing method in rat. The genitofemoral motonucleus

of normal male and female adults were compared. And after unilateral orchiectomy in

the males less than 24 hours of age, the ipsilateral and the contralateral

genitofemoral motonucleus were compared in adult. Finally after bilateral

orchiectomy in he males less than 24 hours of age the genitofemoral motonufleus was

observed in adult according to the neonatal compensation of androgens.

The results obtained are summarized as follows:

1. In the genitofemoral motonucleus of males and females, the location of the

motonucleus were similar, but the number and the size of the motoneuron of males

were larger than those of females

2. The unilateral orchiectomy in neonate caused ipsilaterally atrophy of the

cremasteric muscle in adult, but the size of the ipsilateral genitofemoral

motoneuron was lager than that of the contalateral side, and any significant

difference in the number of the genitofemoral motoneuron was not observed in either

side.

3. The bilateral orchiectomy in neonate caused atrophy of the cremasteric muscle

and decreased the size and the number of the genitofemoral motoneuron in adult.

4. The neonatal compensation of the androgen after the bilateral orchiectomy

could not prevent atrophy of the cremasteric muscle, but maintained the size and

the number of the genitofemoral motoneuron in adult. These effects of the androgens

on the genitofemoral motonucleus are obvious in dihydrotestosterone rather than

testosterone.

From the above results, sexual difference of the genitofemoral motonucleus was

confirmed, and it is concluded that the neonatal androgens affects directly size

and number of the genitofemoral motoneurons. Therefore there could be the process

that androgens affects genitofemoral motonucleus and genitofemoral motonucleus

affects testicular descent in neonatal rat. And dihydrotestosterone is regared as

important androgen in this process.

[영문]

It is generally accepted that androgens and gubernaculum testis play a part in testicular descent. In neonatal rat, division of the genitofemoral descent of testis caused atrophy of cremasteric muscle and diturbed normal descent of testis. The gubernaculum testis is regarded to be richly innervated by the genitofemoral

nerve. So the genitofemoral nerve seems to be closely related to the androgens during testicular descent. Recently it is observed that the genitofemoral motonucleus of rat showed sexual difference. As the other motonucleus showing sexual difference the genitofemoral motonucleus is might be altered morphologically

by manipulation of neonatal androgens. Therefore This experiment was designed to illustrate morphologically the relation between the androgens and the genitofemoral motonucleus using retrograde tracing method in rat. The genitofemoral motonucleus of normal male and female adults were compared. And after unilateral orchiectomy in the males less than 24 hours of age, the ipsilateral and the contralateral genitofemoral motonucleus were compared in adult. Finally after bilateral orchiectomy in he males less than 24 hours of age the genitofemoral motonufleus was

observed in adult according to the neonatal compensation of androgens.

The results obtained are summarized as follows:

1. In the genitofemoral motonucleus of males and females, the location of the motonucleus were similar, but the number and the size of the motoneuron of males were larger than those of females

2. The unilateral orchiectomy in neonate caused ipsilaterally atrophy of the cremasteric muscle in adult, but the size of the ipsilateral genitofemoral motoneuron was lager than that of the contalateral side, and any significant difference in the number of the genitofemoral motoneuron was not observed in either side.

3. The bilateral orchiectomy in neonate caused atrophy of the cremasteric muscle and decreased the size and the number of the genitofemoral motoneuron in adult.

4. The neonatal compensation of the androgen after the bilateral orchiectomy could not prevent atrophy of the cremasteric muscle, but maintained the size and the number of the genitofemoral motoneuron in adult. These effects of the androgens

on the genitofemoral motonucleus are obvious in dihydrotestosterone rather than testosterone.

From the above results, sexual difference of the genitofemoral motonucleus was confirmed, and it is concluded that the neonatal androgens affects directly size and number of the genitofemoral motoneurons. Therefore there could be the process that androgens affects genitofemoral motonucleus and genitofemoral motonucleus

affects testicular descent in neonatal rat. And dihydrotestosterone is regared as important androgen in this process.