Immunohistochemical evidence for the presence of tryptophan hydroxylase and serotonin in the rodent Harderian gland

Abstract

The Harderian gland is considered as being an extrapineal source of melatonin. In most rodents, the Harderian gland contains two epithelial cell types (I and II). The aim of this study has been to define which cell type is involved 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 is involved in indoleamine synthesis in the rodent Harderian gland.

Long‐term daily melatonin infusion induces a large increase in N‐acetyltransferase activity, hydroxyindole‐O‐methyltransferase activity, and melatonin content in the Harderian gland and eye of pinealectomized male Siberian hamsters (Phodopus sungorus)

“…A variety of secondary functions have also been ascribed, e.g., a site of immune responses, a source of pheromones and/or thermoregulatory lipids, and a source of photoprotective secretions [for reviews see Sakai, 1981;Payne, 1994]. In addition, these glands share a common biochemistry with the pineal gland and retina with respect to the produc-tion of melatonin [Pévet et al, 1980;Hoffman et al, 1985;Menendez-Pelaez et al, 1991, 1993Djeridane et al, 1998Djeridane et al, , 1999. Several studies suggest that the biochemical pathway for melatonin synthesis is similar within the three structures, with serotonin being acetylated into N-acetylserotonin by N-acetyltranferase (NAT), then O-methylated into melatonin by hydroxyindole-O-methyltransferase (HIOMT) [for reviews see Reiter, 1991;Menendez-Pelaez et al, 1993;Nowak and Zawilska, 1994].…”

Coexpression of MT1 and RORα1 melatonin receptors in the Syrian hamster Harderian gland

“…Porphyrin and melatonin synthesis, as well as antioxidant enzyme activities, in the HGs display a different pattern between male and female Syrian hamsters. Thus, females, which are subject to porphyrin‐dependent phototoxicity due to the porphyrin accumulation in their glands and they produce more melatonin than do those of males [26–28]. These differences between sexes in the HG were also maintained in the immunohistochemical localization of ROR α 1 in the cells.…”

Immunohistochemical characterisation of epithelial cells of rodent harderian glands in primary culture

“…: j33 03 88 35 85 15 ; fax : 33 03 88 24 04 61n ; e-mail : djeridane!neurochem.ustrasbg.fr (Brownscheidle and Niewenhuis, 1978 ;Payne et al 1992 ;Schreckenberger and Reuss, 1993 ;Djeridane, a, 1996. Moreover, we have recently demonstrated by means of immunohistochemistry on tissue sections, using serotonin (melatonin precursor) and tryptophan hydroxylase (the rate-limiting enzyme for serotonin synthesis) antibodies, that the indoleamine synthesis occurs in the type I cell (Djeridane et al 1999).…”