During the histological study of sperm invasion phenomenon, it was noticed that the head of the spermatozoon stained metachromatically with toluidine blue, and, moreover, that the basophilia of the spermatozoon diminished gradually as it was released from the seminiferous eepithelia and reached epididymis.
The finding was of interest because it might elucidate chemical changes involved in the maturing phenomenon of germ cells. So the nature of this metachromatic substance were studied in relation to morphological changes of the maturing spermatozoon.
Materials were obtained from men by biopsy or at operation. Rabbits testicles were also studied. They were fixed in absolute alcohol and embedded in paraffin, cut, and stained with the buffered (Walpole buffer ranging from pH 1.2-4.2) aquaeous toluidine blue solution. Fixatives containing heavy metal salts end formaldehyde, usually used in testicular tissues, inhibited or abolished metachromasia. Various other histochemical procedures were run in parallel sections.
The results obtained may be summarized as follows. The head of the maturing spermatozoon stained metachromatically above pH 2.3. The metachromasy was first noticed when the nuclei of spermatids took the form of spermatozoon heads and disappeared after they lost contast with Sertoli nuclei. So the appearance and disappearance of metachromasy roughly coincided with that of acrosomic material.
As metachromasy was saliva, and hyaluronidase resistent, it was suggested that the metachromasy was not due to polysaccharide known to be present in germ cells. As will be reported in the later issues, the metachromatic staining was most likely due to DNA, especially to highly polymerized one.
In some of the specimens, numerous intensely basophilic, but not metachromatic corpuscles were noticed at the margin of seminiferous epithelia. These corpuscles corresponded with “residual body” of Leblond and Clermont, the exact chemical nature of which has not been established. The basophilia of these corpuscles completely disappeared after the treatment with ribonuclease suggesting that these were composed of RNA.