Comparison of Porphyrin Producing Enzyme Activities in Harderian Glands of Mice and Other Rodents. ∗

Abstract

Summary and conclusions

1. A quantitative study was made of porphyrin producing enzyme activities of Harderian glands, livers, brains, and muscles of mice, rats, hamsters, rabbits, and guinea pigs. 2. The tissues used were obtained from commercially available male albino rats, rabbits, guinea pigs, and brown hamsters, and strong A strain mice. 3. A buffer-saline solution or extract was made from a weighed quantity of each homogenized tissue mentioned. Measured amounts of these extracts were mixed with 0.01 M solution of δ-aminolevulinic acid and incubated at 37° for 24 hours. 4. Harderian gland extracts of mice and rats showed greatest amount of porphyrin producing enzyme activity, while the same tissue from the hamster was only slightly lower in enzyme activity. The 2 lobes of the Harderian gland of rabbit and guinea pig contained far less porphyrin producing enzyme. The white fluorescent antero-dorsal lobe of the rabbit contained considerably greater quantities of porphyrin producing enzymes than the grey-reddish postero-ventral lobe. 5. Liver, brain, and muscle extracts of the same rodent revealed amounts of porphyrin producing enzyme, uniform for tissue in various rodents and these values compared favorably with previous values determined for same tissues in the mouse. 6. Because of great variation in amounts of enzyme in various Harderian glands, the liver homogenate extract from rat and hamster contained less porphyrin enzyme than the Harderian gland. The reverse, however, was true in rabbit and guinea pig, for liver tissue contained more porphyrin producing enzyme than the Harderian glands of these rodents. It may be concluded that porphyrin produced by Harderian glands may have some function. This comparative study failed to give any clue as to what the function may be.