Y. Djeridane et al., Immunohistochemical evidence for the presence of tryptophan hydroxylase and serotonin in the rodent Harderian gland, CELL TIS RE, 296(3), 1999, pp. 517-523
The Harderian gland is considered as being an extrapineal source of melaton
in. In most rodents, the Harderian gland contains two epithelial cell types
(I and IT). The aim of this study has been to define which cell type is in
volved in indoleamine synthesis. The presence and localization of serotonin
(melatonin precursor) and tryptophan hydroxylase (the rate-limiting enzyme
for serotonin synthesis) have been investigated by immunohistochemistry in
male Wistar rats, Syrian hamsters and Djungarian hamsters. The results of
the present study show that immunoreactivity for tryptophan hydroxylase and
serotonin is confined to the type I cell, suggesting that this cell type i
s involved in indoleamine synthesis in the rodent Harderian gland.