Pituitary control of mouse testis in hereditary dwarfism: Histological and cytochemical observations

The weight, histology, and cytochemistry of the testis in hereditary dwarf mice were compared with those of normal litter-mates; the effect of pure pituitary gonadotropic hormones was also investigated, with particular emphasis on the cytochemistry of the Leydig cells. In dwarfs, the testes were found to be undersized and underdeveloped; 3β-hydroxysteroid dehydrogenase, α-naphthylesterase, and acid α-naphthylphosphatase activities in the Leydig cells were scarce; in addition, there was a lack of alkaline α-naphthylphosphatase in the basement membranes. Administration of pure FSH or prolactin led to an increase of testis weight, but could not establish either normal histology or normal cytochemistry; administration of ICSH, either alone or associated with FSH, caused a more marked weight increase, stimulated spermiogenesis, and partly restored to normal the cytochemistry of the Leydig cells and the basement membranes. In no case did hormonal treatment establish a completely normal morphology of the testes of the dwarf animals. These results appear to indicate that ICSH has a direct influence on the enzyme activities of the Leydig cells.