Abstract
Abstract: :
Purpose:Prolactin (PRL) is the primary lactogenic pituitary hormone that plays an essential role in many aspects of reproduction, functional development and morphogenesis for mammary gland. Hyperprolactinemia was found in 46% of patients with primary SS, correlation between high levels of PRL and active disease has been observed, however the precise role of PRL in exocrine glands remains obscure and controversial. To further define the role of PRL, we have generated transgenic rats which overexpress PRL in lacrimal and salivary glands. Methods:We constructed Wister background transgenic rats (TG) in which the expression of rat PRL cDNA was regulated by the salivary gland tissue-specific Lama6 promoter. We examined the expression of PRL by Northern blotting in the various organs of TG and found PRL expression in the lacrimal and salivary glands. Results:Histological findings indicated that PRL TG had no tissue alteration in the glands. The average saliva and tear volume of PRL TG was significantly higher than non-transgenic rats. After irradiation with 15 Gy, lacrimation and salivation decreased dramatically and began to improve gradually with advancing age in contrast to those of non-transgenic rats. There were no significant gender differences. Circulating autoantibodies were not detected. Time-dependent amylase expression (secretory marker) and phosphorylation of CREB (cAMP response element binding protein) were detected in human salivary epithelial cell line treated with rPRL (1mg/ml) in vitro. Conclusion:These results suggest that PRL significantly enhance lacrimation and salivation by cyclic AMP response through phosphorylation of CREB (ser133). PRL may be clinically useful in sicca symptoms associated with Sjogren's syndrome.
Keywords: 370 cornea: basic science • 372 cornea: epithelium • 376 cornea: tears/tear film/dry eye