ISSN:
1432-119X
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Medizin
Notizen:
Abstract Retinoic acid (RA), through its cognate receptors (retinoic acid receptors,RARs), plays an important role in the ontogenesis and maintenance of the normal function of murine Harderian and submandibular glands. In the present study, autoradiography was used to study RA binding to these glands. Both glands showed high radioactive labelling after [14C]-RA administration in normal and partially vitamin A-deficient (VAD) mice. The peak uptake was at 6 h after [14C]-RA administration in normal mice and at 0.5 h in VAD mice. At 24 h, RA binding remained high in normal mice, while it decreased significantly in VAD mice. In western blots with an antibody recognizing all forms of RARs, a band of molecular weight 51 kDa was seen in homogenates of both glands. Immunohistochemically, RAR staining was found in the nuclei of the glandular cells. The Harderian gland exhibited more intense staining than the submandibular gland. In the latter, the most intense staining was seen in the acinar cells, followed by the intercalated duct cells. The granular convoluted tubule showed weak immunostaining and the striated duct was negative. In the Harderian gland, RAR immunostaining was observed in both type I and II cells, but only part of them stained with RAR antibody. The expression of RARα, β, and γ transcripts was studied by in situ hybridization using specific oligonucleotide probes. The cell-specific expression of RARα mRNA in the submandibular gland corresponded to the RAR proteins detected by immunohistochemistry, while the RARβ transcript was mainly seen in the striated duct. The transcripts of RARα and β were evenly distributed in type I and II glandular cells of the Harderian gland. RARγ labelling was below detectable levels in both glands. This result suggests that RA and RARs regulate the functions of Harderian and submandibular glands in a cell-specific manner.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/s004180050047
Permalink