S.C. Rappaport

Direct Radioimmunoassay (RIA) of salivary testosterone: correlation with free and total serum testosterone

Simple and sensitive direct RIA for determination of salivary testosterone was developed by using RSL NOSOLVEX TM (125 1) kit produced by Radioassay System Laboratories (Carson, California). In addition, a relationship between salivary and serum free and total testosterone concentrations was studied in randomly selected 45 healthy subjects, 5 females on oral contraceptive pills and 28 hypertensive patients on various treatment regimens. The lowest weight of testosterone detectable by our modified method was equivalent to 1 pg/ml of saliva, taking into account analytical variability. Intra- and interassay coefficients of variation were 5.09 +/- 2.7% and 8.2 +/- 5.9% respectively. Statistically significant correlations were found between salivary and serum free testosterone (r = 0.97) and salivary and serum total testosterone concentrations (r = 0.70-0.87). The exception to this was a group of hypertensive females in which no correlation (r = 0.14) between salivary and total serum testosterone was found. It is also of interest that, while salivary testosterone was significantly increased in subjects taking oral contraceptives and most of the hypertensive patients the total serum testosterone concentration was in normal range. Our findings suggest that determination of salivary testosterone is a reliable method to detect changes in the concentration of available biologically active hormone in the circulation.

Cellular Regulation of the Metabolism of Androgens in Rat Oral Mucosa. III. Activation of Δ4-3-ketosteroid-5α-A Ring Reductase Enzyme System by 5,5-Diphenylhydantoin

Systemic pretreatment of rats with diphenylhydantoin (DPH) or its addition into an in vitro assay increases 5α-reduction of testosterone by the oral mucosa. Enzyme kinetic studies showed that DPH binds to the enzyme and probably activates it by an allosteric mechanism.

Effect of Progestins on Androgen Δ4-3-Ketosteroid-5α-A-Ring Reductase System in Rat Oral Mucosa

Rat oral mucosa microsomal Δ 4-3-ketosteroid-5α-A-ring reductase enzyme system, reducing testosterone and 4-androstenedione, was found to be inducible by systemic administration of medroxyprogesterone acetate (MPA). MPA, when used in a mixture with testosterone and/ or 4-androstenedione in vitro, acted as a competitive inhibitor of the reduction of these substrates.

Phenytoin effect on the proliferation of rat oral epithelium is mediated by a hormonal mechanism

Systemic pretreatment of male rats with phenytoin (PHT) (30 mg/100 g body weight) significantly (P less than 0.001) increased mitotic frequency, shortened mitotic duration and renewal time in the basal cells of the oral epithelium. This effect of PHT was abolished by simultaneous s.c. injection of cyproterone acetate (CyA) (50 micrograms/100 g body weight) or by castration. CyA treatment of intact rats or castration further decreased mitotic frequency, prolonged mitotic duration and turnover time in the oral epithelium. The effect of castration was reversed by the simultaneous s.c. injection of testosterone propionate (Tp) (50 micrograms/100 g body weight). These results suggest that PHT effect on epithelial proliferation is mediated by a hormonal mechanism.

Cellular Regulation of the Metabolism of Androgens in Rat Oral Mucosa: I. Effect of Medroxyprogesterone Acetate (MPA) on the Soluble Supernatant (Cytosol) Activating Microsomal Δ4-3-Ketosteroid-5α-Reductase and 17β -Hydroxysteroid Oxidoreductase Enzyme Systems

Soluble supernatant (cytosol) of rat oral mucosa was found to contain a factor accelerating the activity of microsomal Δ4-3-ketosteroid-5α-reductase and 17β-hydroxysteroid oxidoreductase enzymes metabolizing testosterone. Systemic administration of medroxyprogesterone acetate further increased this cytosolic activity.

Metabolism of Androgens by Human Periodontal Ligament

The metabolism of androgens (testosterone and androstenedione) has been studied in healthy and diseased human periodontal ligaments. An increased activity of 17β-oxidoreductase and 17-keto-5α-A-ring reductase and decreased activity of 17β-hydroxy-5α-A-ring reductase, 3αβ-oxidoreductase and 5β-A-ring reductase have been found in diseased periodontal ligament.

Biosynthesis of 17β-estradiol and Its Binding to Specific Receptors in Human Gingiva

An increased biosynthesis of 17β-estradiol was found by microsomes obtained from the inflamed human gingivae when compared to those from healthy and hyperplastic tissues. In contrast, binding of estradiol to cytoplasmic receptors was increased only in hyperplastic tissue and was independent of the amount of estradiol formed.

Cellular Regulation of the Metabolism of Androgens in Rat Oral Mucosa. II. Product Activation of 17 β-hydroxysteroid Oxidoreductase Enzyme System

Product activation of 17β-hydroxysteroid oxidoreductase for testosterone and androstenedione was established using the enzyme preparation from rat oral mucosa. It is suggested that this activation could be due to the conformational changes of the enzyme.