Cell proliferation as a function of metabolism in three species of native rodents

• 1.

  1. Incorporation of the thymidine analog 5-¹³¹iodo-2′-deoxyuridine (¹³¹IUDR) was measured in vivo in cotton rats, Sigmodon hispidus, white-footed mice, Peromyscus leucopus and pine voles, Microtus (Pitymys) pinetorum.

• 2.

  2. The percentage of initial activity retained per 10 g of body weight 48 hr post-injection o f 1 μc of ¹³¹IUDR was used as an index to cell proliferation in the intestinal epithelium. The values were: Sigmodon male 0·22, female 0·26; Peromyscus male 0·68, female 1·00; Microtus male 1·40, female 1·50.

• 3.

  3. When measurements of ¹³¹IUDR retention were plotted as a function of average oxygen consumption for these species the resulting regression equation indicated that for every 1 ml increase in oxygen consumption there was a doubling in cell proliferation. Animals tested which had high rates of metabolism likewise had high rates of cell proliferation.