Differential Distribution of An Estrogen Receptor in the Submandibular and Parotid Salivary Glands of Female Rats

Abstract

The purpose of this study was to measure the availability of the estrogen receptor in submandibular and parotid salivary glands in female rats. The presence of a specific, competitive, and saturable estrogen binder in rat salivary gland tissue was determined by saturation analysis and steroid competition in cell-free homogenates of salivary gland tissue from adult ovariectomized females. Scatchard analysis of the data indicated an estrogen receptor content of 1971.1 +/- 651.4 femtomoles/gm of tissue in submandibular salivary gland. This was significantly (p less than 0.01) greater than the number of estrogen binding sites in the parotid gland (457.1 +/- 123.4 femtomoles/gm tissue). Thus, there is a differential distribution in estrogen receptor content between parotid and submandibular salivary glands. The presence of an estrogen receptor in salivary gland tissue may serve to promote gender differences in submandibular salivary gland EGF content, to mediate changes in saliva composition during the female reproductive cycle and to regulate EGF release for cyclic uterine growth.

Multifocal Ductal Cell Hyperplasia in the Submandibular Salivary Glands of Wistar Rats Chronically Treated with a Novel Steroidal Compound

“…In contrast to our findings, the estrogenreceptor has been identified in rat SMG homogenates by others using binding studies (6) or immunohistochemistry in normal and castrated rats (27,31). Although from these studies it was clear that the estrogen-receptor was located in ductal cells, there is no consensus about the cell type that is the most important in this respect.…”

“…Testosterone was found to increase and estrogen and/or progesterone to decrease the total granular duct area considerably (30). Further evidence for a regulatory role of steroids in rat SMG functioning comes from receptor binding assays and immunohistochemical studies demonstrating the presence of estrogen-and progesterone-receptors in the ductal system of the SMG (6,25,27,31). The presence of these hormone receptors suggests that the SMG could be a target in toxicity studies with estrogens, progestagens, and combinations of both.…”

Identification of androgen, estrogen and progesterone receptor mRNAs in the eye

“…If this indication is confirmed by quantitative analysis, then this finding would be consistent with the observations of other investigators. Thus, significant tissue-, gender-and species-differences have been identified in sex steroid receptor mRNA and protein expression, as well as in sex hormone binding activity, nuclear uptake and/or retention in nonocular sites (Abdelgadir et al 1990;Asaithambi et al 1997;Bergman et al 1987;Campbell et al 1990;Godwin & Crews 1999;Roselli & Resko 1997;Sheridan & Weaker 1982;Young et al 1995;Zhang et al 1989). Sex steroids may also up-or down-regulate the levels of their own or other sex steroid receptors (Blanchere et al 1998;Clark et al 1992;Saceda et al 1989).…”

The granular convoluted tubule (GCT) cell of rodent submandibular glands

“…There are only a few studies on receptors for other hormones known to influence the GCT cells, such as the receptors for thyroid hormones, adrenocorticosteroids, progesterone, or estrogens. Campbell et al (1990) and Sakabe et al (1987Sakabe et al ( , 1988 kinetically characterized the receptors for progestin and estrogen in extracts of the rat SMG; the latter authors have immunocytochemically localized them to cells of the GCT and striated ducts. Ozono et al (1991) confirmed the immunohistochemical localization of the progesterone receptor in GCT and striated duct cells and showed that expression of this receptor is increased by estradiol treatment.…”