[Ragged--a new rexoid mutant rat with large sebaceous gland].

A new hair defected mutant rat was established. This mutant was covered with ragged hair since about 10 days of age, then transiently lost most of hair in the back at approximately 5 weeks of age and re-covered with ragged hair thereafter. Thickened eyerids occurred since about 3 weeks of age.

Suprainguinal ectopic scrota of TS inbred rats.

A new rat line (TS inbred rats) showing uni- or bilateral ectopic scrota in about 70% of the males was established. Ectopic scrota were elongated pouches of the thin muscle layer under the suprainguinal body skin, in which hypoplastic testes and epididymides were seen. Genetic analysis revealed that the ectopic scrotum was controlled by multiple genes.

A new male pseudohermaphrodite rat mutant with androgen deficiency.

A male pseudohermaphrodite rat mutant showing a blind-ending vagina, small undescended testes, rudimentary male sex accessory organs and XY karyotype was investigated. Genetic analysis revealed an autosomal single recessive transmission of this defect and indicated that the gene action is restricted to males. Microscopic examination showed an absence of typical Leydig cells in testes of the mutant.

Sperm retention cysts in the efferent duct and testicular atrophy of TE inbred rats.

Sperm retention cysts were observed in the efferent duct of TE inbred rats at 15 weeks of age. Spermatozoa agglutinated in the efferent duct with destruction of the epithelium. Testicular weight increased or decreased.

[Morphological study on the hypoplastic testis with aplasia of the epididymis, ductus deferens, and gland of the ductus deferens in the TW inbred rat].

In the TW inbred rat, about 50% of the males show bilateral or unilateral testicular hypoplasia with aplasia of the ipsilateral epididymis, ductus deferens and gland of the ductus deferens. To investigate the pathogenesis of the testicular abnormality in the TW rats, the weight and morphology of the testes on the aplastic and normal side were studied between one week and one year of age. The weight of the testes on the affected side was greater than those on the normal side at four and five weeks.