High Insulin Tolerance in an Inbred Strain of Mice

Abstract

Survival of a tolerant strain of mice for insulin was the same for intraperit. and subcut. injns., and there were no sex differences. Mice up to 15 days gave about the same response for all strains. The tolerance then diverged. There was increased sensitivity for a Zr strain and a decreased sensitivity for a KL strain. With high doses, death in the KL strain was delayed to 3 and 4 days. The usual maximum is 30 hrs. Strain L (from "Swiss" albinos and one parent of the KL strain) also approached the high tolerance level. At 30-40 days, some KLs tolerated up to 750 times the amt. tolerated by Zrs. The maximum amts. tolerated at 17 g. were, in units/kg., 59 for Zr, 201 for C57 Black, and 18,300 for KL. The lowest killing dose was 1 unit for Zr, 1 for C57 Black, and 240 units for KL. Genetic tests between KL and Zr showed that extreme tolerance may be a single recessive factor. Normal blood sugar analyses gave the following results in mg. %: 170 for Zr, 172 for C57 Black, and 171 for KL.