わが国で分離育成した近交系マウスの発育過程における形態学的細胞学的研究

Morphological and cytological studies on the process of growth to the strains of inbred mice

Nakamura Tsunenori

Morita Haruka

広島大学水畜産学部紀要

Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University

　我国で分離育成した近交系マウスの医学生物学面への実用化の検索目的のーつとして， NC系およびKK系の産仔生後発育とその生殖細胞について形態学的細胞学的観察を行なった.
1. 体重増加は三段階に分けられ生後35-40日令と生後55-60日令に 体重増加の屈折転向点がある.雌雄個体の体重の差および両系統聞の体重の差は生後40日令頃から生ずる.
2. 畢丸降下日令はNC系22-25日， KK系24-28日で両系統聞に有意差が認められた.
3. 腔関口日令はNC系30日前後， KK系32-35日令で両系統聞に有意差がみられた.
4. 腫関口日から正常な性週期をくり返すまでにはKK系は非常に不安定である1週期の長さはNC系4.91±0.26 日， KK系5.80±3.80日であり，両者聞に有意差が認められた.
5. 卵巣重量の増加は生後30-35日令に成熟量IC 達する.
6. 宰丸重量の増加は生後50-55日令までの増加が急速でありそれ以後緩慢である.
7. 精細管口径の発達は生後25日令までは最も急速であり生後55-60日令はやや緩慢で，それ以後は口径は一定する.
8. 両系統における雄の性成熟期は生後50-55日令，雌は30-35日令であり，体の成熟期はこれ等の時期より遅いと考えられた.
9. 精細管内の精子形成期は性成熟期の10-15目前に一応完了するものと考えられ，NC系40日令，KK系45 日令である.
10. 卵巣内の成熟鴻胞は性成熟期の5目前に観察され，NC系25日令， KK系30日令である.多卵性溜胞および多核性漉胞は一般に僅少であるが，他の崎乳動物と同じく幼令期に多く観察された.これは卵巣内のホノレモン調整の不均衡の時期である幼若期に多発すると考えられた.

The present study was undertaken to investigate morphologically and cytologically the process of growth of mice of NC and KK strain.

The data presented in this study are summarized as follows :

1) Body weight is separated into three stages in the process of growth. Remarkable change in growth of body weight occurred in 35 to 40 days (male) and 55 to 60 days (female) of age after birth.
2) Age of descensus testis was found to be 22 to 25 days in NC strain and 24 to 28 days in KK stram.
3) Age of vaginal opening was 30 days in NC strain and 32 to 35 days in KK strain.
4) Sexual cycle of mice generally was variable by strain. NC strain showed a considerably normal sexual cycle in contrast to KK strain.
5) Ovary weight reached a maximum of growth in 30 to 35 days of age， while testis weight reached a maximum growth in 50 to 55 days in both strains.
6) Seminiferous tubules of mice of both strains showed a marked development by 25 days after birth and slowed down from 25 days to 60 days. The diameter of seminiferous tubules showed a constant value in 60 days of age.
7) Microscopical observations revealed that healthy spermatozoa were observed in seminiferous tubules and epididymis in 40 days of age in NC strain and in 45 days in KK strain. Normal majure follicles proceeding prior to the maturation course is abundant in 25 days of age in NC strain and in 30 days of age in KK strain. Polyovular follicles were rare in occurrence showing no difference by strain. Especially， immature mice showed a comparative large number of polyovular follicles and polynuclear follicles in comparison with mature mice.

Biology [ 460 ]

jpn

広島大学水畜産学部

[ISSN] 0440-8756

[NCID] AN00213563