51 This fact is probably due to hormonal protection
in women. With respect to oestrogen, an experimental study has shown that a reduction of oestrogen levels causes alterations in the mechanism of action of insulin.52 Moreover, replacement therapy with natural estrogens reduced insulin resistance, contributing to the control of glucose levels.53 Although promising, these findings demonstrate the complexity of the action of these hormones, especially in hyperglycaemic conditions. In an experimental study on oestrogen replacement therapy, Ceylan-Isik et al. found no positive effects on glycaemic control.40 The present results confirm the diabetic condition of the animals and demonstrate the efficacy of insulin treatment in glycaemic control. In addition, oestrogen at physiological
doses BIBF 1120 mw was important for the regulation of glucose levels. However, further studies are necessary to better understand the mechanism underlying the action of oestrogen and other possible beneficial effects of this hormone. Analysis of the salivary glands showed alterations in the expression of cellular receptors in both untreated diabetic Avasimibe animals and diabetic animals submitted to either treatment alone. In contrast, recovery of the expression of INS-R and ER-alpha occurred in the group receiving oestrogen plus insulin, similar to what was observed in healthy animals. Various factors including hormones act on the homeostatic mechanism in different tissues, such as the salivary glands. Different conditions such as diabetes mellitus can cause alterations in hormone levels. This agrees with studies showing that diabetic women tend to be at a higher risk of sexual dysfunctions.54 Thus, hormone alterations may act in a feedback loop, potentiating the damage caused by diabetes mellitus.
Considering that oestrogen at normal levels plays an important role as an immunoregulator, Ishimaru et al. studied the effects of oestrogen deficiency in an experimental model.17 The authors observed a higher apoptotic activity in salivary glands and an increase of autoimmune lesions, lesions that are common in type I diabetes mellitus. Current evidence also indicates that, in addition to hormone alterations, increased expression of oestrogen receptors localized close the nuclei of epithelial cells is related to the development of adenomas in the salivary glands.55 In this respect, Kumar et al. reported Amylase the involvement of ER-alpha in the development of tumours in glandular tissue.56 These results are important when relating oestrogen to diabetes since glucose metabolism and hyperglycaemic conditions have also been suggested to play a role in the development of cancer.57 and 58 Thus, experimental evidence from animal models indicates that oestrogen alterations may participate in the pathogenesis of salivary gland.59 On the other hand, the oestrogen and their receptors may regulate gene expression and influence crucial physiological events in target tissues.60 According to Tsinti et al.