Specific estrogen receptors in human gingiva

The cytoplasm of normal human male and female gingiva contains a receptor capable of specifically binding 17 beta-estradiol and moxestrol (R-2858) with high affinity (Kd = approximately 3.4 X 10(-10) M) and low capacity (4.5 fmol/mg protein). The binding is sensitive to heat (destroyed by warming to 37 C for 60 min), proteolytic enzymes (pronase, trypsin, and chymotrypsin), and exhibits a pattern of competition similar to that obtained with estrogen receptors from other target tissues. Nuclear uptake of [3H]estradiol was demonstrated by using a dry autoradiographic technique. Specific nuclear localization of [3H]estradiol was found predominantly in basal and spinous layers of gingival epithelium, stromal connective tissue cells (fibroblasts), and endothelial cells and pericytes of small blood vessels in the lamina propria. There was no difference between the Kd values in normal and diseased tissue or between the Kd values or number of binding sites and the age or sex of the patient. However, there was a difference between the amount of estrogen binding sites per mg protein in normal tissue compared to gingiva with dilantin hyperplasia. These results provide the first direct evidence that human gingiva may function as a target organ for estrogens.