Jozef Vittek

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.

The effect of alcohol ingestion on hepatic aromatase activity and plasma steroid hormones in the rat

Chronic alcohol ingestion in the rat resulted in increased hepatic aromatase activity, elevation of plasma estradiol, and a decrease in plasma testosterone levels. Testicular incubation studies indicated that the source of the estrogen was not of gonadal origin but was, most likely, due to increased peripheral conversion. The failure of HCG in vitro to restore testicular secretion of testosterone to normal levels suggested a direct action of alcohol, or a metabolic product, on gonadal secretory processes, as distinct from trophic hormone effects. This study demonstrates that many of the hormonal alterations seen in cirrhosis of the liver in man may be produced directly by alcohol feeding without cirrhotic changes in the rat.

Effect of Chronic Alcohol Use on Hepatic Testosterone 5α-A-Ring Reductase in the Baboon and in the Human Being

Hepatic testosterone 5-alpha-A-ring reductase (HTAR) activity was measured in open liver biopsies in eight alcohol-fed baboons and eight pair-fed controls. The animals were studied after at least 1 yr of alcohol feeding. In the alcholol-fed animals, a significant fall in enzyme activity was noted. This occurred whether the enzyme levels were related to soluble protein, to DNA, or to wet tissue weight, showing that the change was due to a decrease in the specific activity of the enzyme. In addition, aspiration liver biopsy specimens were obtained from 14 men and women with alcoholic liver disease. Again, there was a significant decrease in HTAH activity in these patients compared with a normal population. No relationship was found between hepatic histology and HTAR levels in either the baboon or human population with alcoholic liver disease, suggesting that the changes in enzyme activity were related to an alcohol effect rather than to liver disease per se. This study demonstrates that chronic alcohol use decreases the function of the enzyme which controls an important rate-limiting step in the metabolism of testosterone in the liver and that this effect may be due primarily to alcohol.

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.

Autoradiographic Localization of Dexamethasone in the Rabbit Submandibular Gland

Nuclear localization of 3H-dexamethasone to secretory and duct cells in the rabbit submandibular gland was determined by dry-mount autoradiography. This saturable nuclear binding indicates that glucocorticoid effects on this gland may be mediated by cytosol-nuclear receptors.

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.