The effects of age on the structure and porphyrin synthesis of the harderian gland of the female golden hamster.

The effects of age on structure and porphyrin synthesis were examined in the Harderian gland of the female golden hamster. An age range of 2-24 months was examined. Porphyrin enzyme activity reached a peak at 6 months and then declined; the porphyrin content of the gland (as determined both by biochemical assay and by the number of visible porphyrin accretions) also declined from 6 months. Mast cells, found in large numbers in the actively synthesising female gland, declined with age. Conversely, tubule epithelial cells with large lipid vacuoles (Type II cells--characteristic of the non-synthesising male gland) increased in frequency. There was considerable evidence of degenerative changes in gland structure with age. These included thinning of the tubule walls, invasion of the tubule lumen by neutrophils and the appearance of porphyrin stores within the interstitium of the gland. The latter were either large accretions surrounded by foreign body giant cells, or smaller deposits within individual free macrophages. Changes may be the result of ageing itself, of hormone insufficiency in post-reproductive senescence or inflammatory processes.