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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.

The cytoplasm of normal human male and female gingiva contains a receptor capable of specifically binding 5 alpha-dihydrotestosterone (DHT). This binding has a high affinity for DHT (Kd, approximately 2.2 x 10-9 M) and a low capacity (approximately 190 fmol/mg protein). The binding is extremely heat sensitive and exhibits a pattern of competition similar to that obtained with DHT receptors from other target tissues. The demonstration of a specific DHT receptor in human gingiva provides the first direct biochemical evidence that this tissue may function as a target organ for androgens. There was no correlation between the Kd in normal tissue and gingival hyperplasia or between the Kd or number of binding sites and the age or sex of the patient. However, there sites and the age or sex of the patient. However, there was a significant difference (P less than 0.0005) between the amount of DHT-binding sites per mg protein in normal tissue as compared to gingival hyperplasia (drugs or pregnancy).