ABSTRACT
The isolation and evaluation of thymic extracts, as described in Chapter 11, reasonably pointed to the unknown tin-bearing antioncogenic biochemical having a steroid nature. As noted in Chapter 10, the thymus gland processes cholesterol and cholesterol derivatives. Consequently, one could hypothesize that the anticarcinogenic S factor of extract IIB3 is a tin-cholesterol derivative. In order to assess the merit of this hypothesis a series of tin steroids were prepared by methods described in Chapter 15 and elsewhere. 1 Since the reported molecular weight of S is around 400 daltons, the material promised to be little more than the steroid ring structure with an attached tin. Immediately, two unknowns were encountered. At which of the four principle active sites on the steroid ring might the tin moiety be attached? In order to meet the obvious constraints of covalent bonding, the tin atom must have attached to it one or more other groups — which ones? The literature, of course, was silent as to tin steroids which appear to be a new class of chemical compounds. Therefore, Dr. Sebastian Kanakkanatt of Unique Technologies Inc. (Mogadore, Ohio) synthesized a series of tin steroids wherein both the tin-steroid binding site and the nature of the tin moiety were varied. Furthermore, as seen in the preceding chapter, not only cholesterol and cholesterol derivatives were used as the steroid reactant, but also several of the sex hormones were likewise combined with various organotins; the latter for two reasons: (1) to examine the hypothesis by evaluating not only tin-cholesterol types, but also steroids which ought not to be effective. The sex hormones are implicated as causative factors in normal thymus involution as described in Chapter 10; and (2) to evaluate the effect of variation in the nature of the tin moiety.
