As the result of biological-metabolic experiments with loose-binding glycyl-lycine iron colloid, whict has been proven to be almost an ideal colloid for the use in examining the function of reticulo-endothelial system (as described in Part 1), using mice and rabbits, the following conclusions were drawn.
1. In the case of intravenous injection to mice LD50 of this colloid solution proves to be 1.25 ml/20 g (solution containing 100γ Fe… plus 10 mg/ml of glycyl-lycine), and when 1/3 of this amount is used as a fixed dose for the tracing of the reticulo-endothelial system, there can be observed no side-effects and it yields the desired result.
2. It has been demonstrated that immediately after the in travenous iujection phagocytosis of this colloid solution commences rapidly and Fe… can be detected in reticulo endothelial cells, and subsequently it is utilized for hemoglobin synthesis. Experimentally, it is observed that phagocytotic phase and iron metabolic phase are distinct and in addition, the retension in the reticulo-endothelial system is rapidly released.
3. This iron colloid can reveal precisely any experimental abnormality of the reticulo-endothelial function. It has been shown that the funcfion of reticulo-endothelial system should be studied from two angles of phagocytosis and utilization, and that there is room for further clitical study on the unilateral approach in this study.
4. Compararative studies on the efficiency of commercial, hard-binding iron colloid with this loose-binding colloid have demonstrated that cellular blocking occurs least with this new iron colloid in vivo. In addition, similar comparisons made in vitro likewise verify this point.
5. In the comparison of this colloid with serum iron colloid, no superiority can be seen with either one as regards the efficiency in vivo metabolism. Therefre, it can safely be said that glycyl-lycine iron colloid is superior from the viewpoint of it being a non-biological preparation.
These findings support the author's belief that glycyl-lycine iron colloid is the best available substance at present for the clinical use in exmamining the function of reticulo-endothelial system and also as an excellent therapeutic agent for iron-deficiency anaemia