While the usefulness of the human fetal pancreas transplanted into diabetic humans has yet to be realized, its transplantation into nude mice has revealed some of its potential. In this animal the organ grows in size, during which time differentiation of its endocrine component and maturation of the insulinogenic response to glucose occurs. The results reported in this article expand these results by providing data on the weight and both the insulin and glucagon content of these passaged organs.
Human fetal pancreata of gestational age 14–19 wk were implanted subcutaneously (s.c.) in nude mice and maintained in vivo for 5–54 wk (absolute age 19–68 wk). The implants were then removed and their insulin and glucagon content determined. Both the weight of these implants and their insulin content were positively correlated with the absolute age of the tissue (weight: r = 0.61, P < 0.001; insulin content: r = 0.62, P = 0.0003). The glucagon content bore no relationship to the age. The maximum level of insulin extracted from 30 passaged human fetal pancreata was 0.8 U, a level far below the daily insulin requirements in adult humans. It is suggested that an explanation for this is the site of transplantation used. To compare the s.c. site with the renal subcapsular space, the explants of four fetal pancreata were evenly divided between these two sites. After 11–13 wk, the implants were removed. Those beneath the renal capsule were larger and contained a greater amount of insulin and glucagon than those transplanted s.c.
It is concluded that: (1) the human fetal pancreas implanted in the nude mouse grows and its insulin content increases with time, and (2) the renal subcapsular space is a better site for transplantation in these animals than a S.C. Site.