Urinary and Fecal Coproporphyrin Excretion in Rats: I. Results in Normals and Castrates. ∗

Abstract

Conclusions

1. Excretion of coproporphyrin in the urine and feces of normal rats has been measured in 2 stocks of Sprague-Dawley rats. Collections periods of 48 hours were made. Male rats of these 2 stocks excreted an average of 40 ± 16 and 47 ± 13 μg of urinary coproporphyrin per 48 hours, respectively, while the female rats excreted an average of only 14 ± 5 and 30 ± 12 μg of urinary coproporphyrin per 48 hours, respectively. There was no significant correlation between body weight and urinary coproporphyrin excretion. No significant sex difference was found in the fecal excretion of coproporphyrin; mean values in the various groups ranged from 33 ± 9 to 46 ± 21 μg per 48 hours. Reduced values were found in both male and female rats weighing less than 115 g. In both males and females, over 75% of the urinary and fecal coproporphyrin was type III isomer. 2. The administration of androgen to female castrate rats increased the excretion of coproporphyrin in the urine. The administration of estrogen to male castrate rats caused a decrease in the amount of coproporphyrin in the urine. 3. A diuresis, induced by substituting saline for drinking water, did not increase the urinary excretion of coproporphyrin. 4. Trace amounts of uro-type porphyrins are excreted normally in rat urine and feces. Protoporphyrin is excreted only in the feces.