| Abstract |
Abstract
Background : In order to clarify the signal transduction mechanism in the proliferation/differentiation and saliva synthesis/secretion of salivary glandular cells, the expression and localization of phospholipase D (PLD1 & 2), one of important effector molecules working in response to the activation of intramembranous receptors for the first messengers, mainly autonomic nervous transmitters
Objective : This study proposed to investigate the localization at light and electron microscopic levels of PLD in the mouse submandibular gland (SMG)
Methods : SMGs of male and female mice at postnatal 0, 2, 4 and 8 week were utilized for immunoblotting and immuno-light and -electron microscopic analyses
Results : The expression of PLD1 was non-detectable at birth and it increased and reached a peak at postnatal 4 week (P4W) and P8W and decreased thereafter, while that of PLD2 was already at a substantial level at birth and was intense at P2W and decreased thereafter. The expression of both isoforms showed a female dominance. In accord with the immunoblotting finding, the immunoreactivity for PLD1 was faint throughout the gland at birth, it progressively increased in granular convoluted tubules and striated ducts and the immunoreactive material was deposited along their apical plasmalemma and in the cytoplasm at P2W-P8W. On the other hand, PLD2-immunoreactivity was distinctly positive in terminal tubule cells and ductal cells at birth, and it increased along both apical and basal plasmalemma of ductal cells at P2W, and it progressively attenuated thereafter. In contrast, acinar cells were immunonegative for PLD1 or PLD2 throughout the postnatal stages
Conclusions : The present postnatal finding suggests that PLD1 is involved intimately in the signaling for saliva production of ductal cells while PLD2 more in the proliferation/differentiation of glandular cells than the saliva production
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Publication
Journal Publication
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