組織培養系を用いた幼若家兎代償性睾丸肥大の実験的考察

Abstract

幼若家兎を用いた代償性睾丸肥大の発生, およびそのmechanismにおけるgrowth factor (s)に対して, 組織培養系を用いた細胞レベルでの考察を加えた.1)幼若家兎の一側睾丸摘出後4週間経過した対側睾丸重量の平均値は, 0.453 mg/gr(睾丸重量/体重)であり, 対照群(0.258 mg/gr)に比し有意に(p<0.001)増量していた.2)摘出睾丸の初代培養細胞に, 定期的に採取した血清を作用させてDNAおよびRNA合成能を測定したところ, 摘出後4日目の血清添加により合成能は最大となった.3)睾丸摘出4日目の血清中に存在すると思われるgrowth factor (s)はサルおよびラットの睾丸細胞, ならびに幼若家兎の皮膚線維芽細胞に対しては全く影響を持たず, きわめて高い種および臓器特異性を有していた.4)組織学的には精細管の増生が顕著であり, growth factor (s)としてはFSHの可能性が考えられる

The regulation of compensatory testicular growth after hemicastration using prepubertal rabbits (less than 1000 g) was analyzed by weight increase of the remaining testis. At the 4th week postoperatively, the testis of hemicastrated rabbits weighed about 0.453 mg/g (testis weight/body weight) while the testis of sham operated rabbits weighed about 0.258 mg/g (testis weight/body weight). Thus, the testis of hemicastrated young rabbits developed compensatory growth up to about twice the size of control rabbit testis. This was further confirmed by the histological analysis of testes, in which the number of seminiferous tubules of hemicastrated rabbits was doubled as compared with the sham operated animal. The rabbit testicular cells obtained from the above operated testis could be cultured in monolayer form. These cultured monolayered cells were synchronized by culture in serum-free minimum essential medium (MEM) for 24 hrs. These primary rabbit testicular cells synthesized more DNA and RNA when cultured in a medium that contained hemicastrated rabbit serum, than in that containing normal serum. Stimulation of 3H-thymidine and 3H-uridine incorporation reached the maximum on the 4th day postoperation and thereafter DNA synthesis decreased rapidly whereas RNA synthesis decreased gradually. However, these cells cultured in MEM containing sham operated serum showed no significant increase in 3H-thymidine or 3H-uridine incorporation. Thus, the hemicastrated serum must contain a testis growth stimulating factor(s). Primary monkey testicular cells and primary rat testicular cells were treated with hemicastrated rabbits serum. The testicular cells of these animal species were insensitive to growth stimulation by the hemicastrated serum, which suggests that the testicular growth stimulation is species specific.(ABSTRACT TRUNCATED AT 250 WORDS)