Lethal factor released from submandibular grafts in mice

The present series of experiments clearly demonstrates the existence of the lethal factor in the submandibular gland of male BALB/c mice. This lethal factor was released from the submandibular gland of male mice when the glands were transplanted autologously into submandibular-sialoadenectomized male mice or isologously into normal intact adult male or female mice. Neither the sublingual nor the parotid grafts demonstrated the same effect. The lethal effect was not observed in the experiments with submandibular grafts obtained from immature male or mature female mice. As a host, the female mouse was found to be more susceptible to the lethal factor. There was a linear relationship between the strength of the lethal factor and the number of submandibular grafts used. The site of production of the lethal factor is unknown. It was extremely unusual to see the death of host mice which merely received a normal organ other than the submandibular gland.

Testosterone dependency of the lethal factor in mouse submandibular gland isografts

In previous papers we have described the presence of the lethal factor which was exerted by the submandibular glands transplanted from adult male donor mice autologously and isologously. The lethal factor was not demonstrated by submandibular grafts obtained from immature male or adult females. We then hypothesized that the lethal factor may be directly related to sexual maturation of male donors and also to an action of testosterone. To clarify this hypothesis, the present experiments were carried out, and the results obtained indicate that the lethal factor is testosterone-dependent. Submandibular grafts obtained from both immature male and adult female donors which received pretreatment with testosterone enanthate exerted a lethal effect on the hosts. Large dosages of testosterone enanthate, which obviously increased the lethal factor level in the submandibular gland, did not kill normal intact adult mice; nor did it increase the mortality of bilaterally submandibular-sialoadenectomized immature mice beyond that of controls without testosterone treatment, when they were not transplanted. Although the site of production of the lethal factor is unknown, we postulate that the submandibular gland is the source.