Antioxidant response of osteoblasts to doxycycline in an inflammatory model induced by C-reactive protein and interleukin-6.

OBJECTIVES: Investigation of osteoblastic responses to oxidative stress, induced by C-reactive protein (CRP) and IL-6 and ameliorating effects of doxycycline (Dox); using assays for 5-alpha dihydrotestosterone (DHT) as an antioxidant marker of healing. IL-6 and CRP are risk markers of periodontitis and prevalent comorbidities in periodontitis subjects. METHODS: Confluent monolayer cultures of osteoblasts were incubated with radiolabelled testosterone (14C-T) as substrate, in the presence or absence (Control) of pre-determined optimal concentrations of CRP, IL-6, Dox; alone and in combination (n=8) for 24h in MEM. The eluent was solvent-extracted for steroid metabolites. They were separated using TLC in a benzene/ acetone solvent system 4:1 v/v; and quantified using radioisotope scanning. The identity of formed metabolites was confirmed using the mobility of cold standards added to the samples and disclosed in iodine. Further confirmation of the authenticity of DHT was carried out by combined gas chromatrography-mass spectrometry, after derivatization to pentafluorobenzyloxime trimethyl silyl ether. RESULTS: The yields of DHT from 14C-testosterone showed 2-fold and 1.8-fold- inhibition in response to IL-6 and CRP respectively and 28% stimulation in response to Dox, via the 5-alpha reductase pathway. The combination of IL-6 + CRP showed a 2-fold reduction in the yields of DHT, elevated to control values when combined with Dox (n=8; p<0.001). Yields of 4-androstenedione showed an inverse relationship to those of DHT, in response to the agents tested, in keeping with the 17-beta hydroxysteroid dehydrogenase pathway. CONCLUSIONS: Inhibition of DHT synthesis in osteoblasts by IL-6 and CRP was overcome by doxycycline. Oxidative actions of IL-6 and CRP; and antioxidant actions of Dox are reinforced by the metabolic yields of DHT in response to agents tested. Using a novel metabolically active model allows closer extrapolation to in vivo conditions; in the context of adjunctive therapeutic applications for periodontitis and prevalent comorbidities.

Analysis of histopathological and immunohistochemical differences of oral squamous cell carcinoma in young and old patients in Sri Lanka.

BACKGROUND: Oral squamous cell carcinoma (OSCC) most commonly occurs in the middle-aged and older individuals. The purpose of the present study was to evaluate the histopathological and immunohistochemical differences of the younger (<40 years) and the older (more than 50 years) groups. METHODS: The histopathological parameters of 112 patients (younger 56 and older 56) were compared according to three grading systems (Broder JAMA 1920; 74: 656, Anneroth et al. Scand J Dent Res 1987; 95: 229, Bryne et al. J Pathol 1992; 166: 375) and as individual histopathological parameters. Further, the expression of p53 and Proliferative Cell Nuclear Antigen (PCNA) index was also compared. RESULTS: Although there was no significant difference between two groups regarding the three grading systems, a significantly higher number of nuclear aberrations was found in younger group (P<0.001). Interestingly, higher number of mitoses (P<0.05) and lymph node metastasis (P<0.05) were observed in the older group (P<0.05). Furthermore, significantly a higher PCNA index was found in the older group (P<0.005). CONCLUSIONS: Although tumours of the young patients showed more nuclear aberrations, OSCC of the older patients is proliferative and showed higher metastatic rate.

Demographic, aetiological and survival differences of oral squamous cell carcinoma in the young and the old in Sri Lanka.

Oral squamous cell carcinoma (OSCC) is a major oncological problem in many regions of the world where tobacco habits are practiced in the form of chewing and/or smoking with or without alcohol intake. It accounts for 16.5% of all cancers in Sri Lankan patients with a male:female ratio of 4:1. In Sri Lanka nearly 5% of OSCC are diagnosed in young patients. This comparative study describes, demographic, aetiological and survival data from young and old patients with OSCC (n=56). Both younger and older groups showed a marked male predilection (male:female ratio was 4:1 and 3.7:1 in younger and older groups respectively). Tongue was the commonest site for younger group (41%, P<0.01) whilst buccal mucosa (37.5%, P<0.05) and alveolar mucosa (25%, P<0.01) were for older group. 39% of cancers in younger group were not associated with any identifiable risk factor (P<0.01) and 70% of SCC of the tongue has no associated habits (P<0.01). SCC of the tongue in the younger group shows poor prognosis than the older patients. Three-year survival rate for the total number showed no significant difference in two age groups. Survival appeared to be better in patients without associated habits in the older group.

Modulation of androgen metabolism by phenytoin, oestradiol and tamoxifen in human gingival fibroblasts.

OBJECTIVES: The aim of this investigation is to study androgen metabolism in gingival fibroblasts in response to phenytoin, oestradiol and the antioestrogen tamoxifen, in order to establish the possible role of hormones in the aetiopathogenesis of phenytoin-induced gingival overgrowth. MATERIALS AND METHODS: Six cell lines of human gingival fibroblasts were established in monolayer culture in Eagle's minimum essential medium. Duplicate incubations were performed independently with radiolabelled testosterone and 4-androstenedione, respectively (14C-T/14C-4-A), with optimal concentrations of phenytoin, oestradiol and tamoxifen alone and in combination. At the end of a 24-h incubation period, the medium was solvent extracted for steroid metabolites, which were separated by thin layer chromatography and quantified using a radioisotope scanner. RESULTS: The substrates were metabolised mainly to the diols, 5alpha-dihydrotestosterone (DHT) and 4-androstenedione or testosterone, with the two substrates used. The trends were that phenytoin and oestradiol significantly elevated the yields of the androgens DHT, diols and 4-A/testosterone from both substrates while tamoxifen inhibited the stimulatory effects of oestradiol and phenytoin alone and in combination (n=6; p<0.01, one-way anova). CONCLUSION: Specific hormone-mediated activity in response to phenytoin could contribute to the pathogenesis of gingival overgrowth, which can be decreased by the anti oestrogen tamoxifen.

Anabolic potential of fibroblasts from chronically inflamed gingivae grown in a hyperglycemic culture medium in the presence or absence of insulin and nicotine.

BACKGROUND: Impaired fibroblast function due to hyperglycemia shows reversal in response to insulin. The aim of this investigation was to use a hyperglycemic cell-culture model to study the anabolic products of androgen metabolism in fibroblasts in response to insulin and nicotine. METHODS: Human gingival fibroblasts were derived from chronically inflamed gingivae of six nondiabetic periodontal patients with no history of smoking. Six cell lines were established in monolayer culture in 24 well multiwell plates, and duplicate incubations were performed with each cell line for all three experiments. Eagle's minimum essential medium was used in a range of individual experiments, with radiolabeled testosterone as substrate, in the presence or absence of (1) glucose (1 to 4,000 microg/ml); (2) insulin (1 to 100 microg/ml) independently; (3) an effective concentration of glucose (500 microg/ml) with serial concentrations of insulin (1 to 100 microg/ml); and (4) effective concentrations of nicotine (250 microg/ml), glucose, and their combinations in response to insulin (5 microg/ml). The controls contained no agents other than the radiolabeled substrate. At the end of a 24-hour incubation period, the medium was solvent extracted with ethyl acetate, and androgen metabolites were separated by thin-layer chromatography and were quantified using a radioisotope scanner. RESULTS: The androgen substrate 14C-testosterone was metabolized mainly to 5alpha-dihydrotestosterone (DHT) and 4-androstenedione. (1) Glucose at a concentration of 500 microg/ml reduced yields of DHT by 36% (n = 6; P < 0.01). (2) Insulin caused a small but significant inhibition of DHT in normoglycemic cells. (3) Serial concentrations of insulin significantly counteracted the inhibitory effects of glucose on the yields of DHT (n = 6; P < 0.01). (4) The independent inhibitory effects of nicotine and glucose on metabolic yields of DHT were marginally more pronounced in combination but significantly overcome in the presence of insulin. CONCLUSION: Human gingival fibroblasts obtained from chronically inflamed tissue of nondiabetic patients demonstrated that the inhibitory effects of glucose and nicotine on androgen metabolism can be overcome by insulin, in varying degrees.

Androgen metabolic response to indomethacin and the alkaline phosphatase inhibitor levamisole in fibroblasts.

OBJECTIVES: The aim of this investigation is to study the effects of indomethacin (I) and the alkaline phosphatase (ALP) inhibitor levamisole (L) on androgen 5alpha-reductase expression in gingival and periosteal fibroblasts, in the context of repair in the periodontium. Chronically inflamed human gingival fibroblasts (HGF) were used to demonstrate the comparative effects of L on HGF and human oral periosteal fibroblasts (HPF). MATERIAL AND METHODS: Monolayer cultures of six cell lines of HPF of the fifth to ninth passage were incubated in duplicate with 14C-testosterone/14C-4-androstenedione as substrates in Eagle's MEM; I was added at concentrations of 1 and 3 microg/ml in the presence or absence of the established inhibitory concentration of 30 microg/ml L and incubated for 24 h. The medium was solvent extracted for radioactive metabolites, separated by thin layer chromatography and quantified. RESULTS: L caused 50% inhibition of 5alpha-reductase and 17beta-hydroxysteroid dehydrogenase activity in HGF. In HPF, 5alpha-reductase expression was enhanced by I with both substrates, by 65-76% (n = 6; p<0.01), inhibited by 30-50% (n = 6; p<0.01) with L and restored to control values in combination. CONCLUSION: Yields of androgen metabolites may be linked to ALP activity, with implications on healing, during adjunctive treatment of inflammatory periodontal disease with I.

The modulation of androgen metabolism by estradiol, minocycline, and indomethacin in a cell culture model.

BACKGROUND: This investigation attempts to clarify the proanabolic effects of minocycline and indomethacin by studying their effects on androgen metabolism and mediation by estradiol. A cell culture model was used with androgen substrates because of the proanabolic effects of androgen metabolites. METHODS: Monolayer cultures of human gingival fibroblasts (HGF) derived from 6 patients were incubated in duplicate with 14C- testosterone or 14C-4-androstenedione as substrates and optimal concentrations of estradiol (E1,3 microgram/ml) and minocycline (M25 microgram/ml) or indomethacin (I, 1 microgram/ml) alone and in combination (E1,3+11 or E1,3+M25 microgram/ml); similar experiments were carried out with human oral periosteal fibroblasts (HPF), M, I, E, and the combinations. At the end of a 24-hour incubation period in Eagle's MEM, the medium was solvent extracted with ethyl acetate and the metabolites were separated by TLC in a benzene:acetone solvent system (4:1 v/v). The separated metabolites were quantified using a radioisotope scanner. RESULTS: Both androgens were metabolized to 5alpha-dihydrotestosterone (DHT) and 4-androstenedione (4-A) or testosterone (T) at baseline and in response to the agents tested, by HGF and HPF. With HGF, there were significant increases in the yields of DHT and 4-A or T in response to M, E, and M+E, resulting in 50% to 2.4-fold increases in these metabolites over control incubations (n = 6; P<0.01). The responses to I and combinations of I+E were similar. HPF also demonstrated significant increases of 29% to 4-fold in the yields of androgen metabolites in response to M, E, and M+E (n = 6; P<0.01). I and E similarly increased the yields of androgen metabolites, alone and in combination. CONCLUSIONS: Adjunctive periodontal treatment with minocycline or indomethacin can contribute to hormone-modulated anabolic responses in males and females in gingival and periosteal fibroblasts derived from a chronically inflamed source.

Dexamethasone-mediated androgen metabolism in human gingival and oral periosteal fibroblasts.

Dexamethasone modulates the effects of other hormones and mediates cell function; the periodontium is a target tissue for androgens. It was therefore relevant to investigate the modulation of androgen metabolism by dexamethasone in cultured human gingival (HGF) and oral periosteal fibroblasts (HPF). Each cell line was incubated in Eagle minimum essential medium with [(14)C]testosterone/[(14)C]4-androstenedione as substrates and serial concentrations of dexamethasone (0.5-50 microg/ml), for 24h; the medium was solvent-extracted, analyzed and quantified for steroid metabolites. In response to dexamethasone, both HGF (n=6) and HPF (n=4) showed up to two-fold increases in the formation of 5alpha-dihydrotestosterone and 4-androstenedione (P<0.01, one-way ANOVA), and 3.6- to 5-fold increases in the formation of testosterone (P<0.001), from [(14)C]4-androstenedione, with some inhibition at higher concentrations. Dexamethasone stimulated the formation of physiologically active androgen metabolites in a dose-dependent manner. These metabolites might therefore contribute to dichotomous effects in connective tissues of the periodontium, dependent on effective concentrations of dexamethasone.

Modulatory effects of indomethacin on androgen metabolism in human gingival and oral periosteal fibroblasts.

The non-steroidal anti-inflammatory agent indomethacin (I) suppresses gingival inflammation and alveolar bone resorption. Androgens particularly 5 alpha-dihydrotestosterone (DHT) have anabolic effects on connective tissue and bone matrices. Human oral periosteal fibroblasts (HPF) and gingival fibroblasts (HGF) instigate healing in inflammatory periodontal lesions. The aim of this investigation was to compare the modulatory effects of I on the metabolism of two androgen substrates in human oral periosteal and gingival fibroblasts in culture. Monolayer cultures of both cell types (5(th)-9(th) passage) were established in Eagle's MEM and incubated with 14C-testosterone/14C-4-androstenedione and serial concentrations of I (0.5-50 microg/ml) for 24 h. The steroid metabolites were solvent extracted from the medium, separated by TLC and quantified using a radioisotope scanner. Both androgen substrates were metabolized mainly to DHT and 4-androstenedione/testosterone respectively, expressing 5 alpha-reductase and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity in both HPF and HGF. There were 51% and 73% increases in the levels of DHT over controls, with HGF and HPF respectively (n = 6; n = 4, P < 0.01) in response to I at 1-5 microg/ml, often reaching control values at 50 microg/ml. The expression of 17 beta-HSD activity showed less stimulation than the levels of DHT. Both androgen substrates were effective in this metabolic conversion, which is applicable to healing responses in both males and females in vivo. There were 57% increases (n = 4; P < 0.01) over controls, in the formation of androstanediol from 14C-4-androstenedione at 10 microg of I, in HPF. This transformation may regulate androgen action in androgen-dependent tissue. In addition to its anti-inflammatory properties, indomethacin can contribute to anabolic reparatory responses, by increasing the expression of steroid metabolizing enzymes in gingival and periosteal fibroblasts, in the inflammatory periodontal lesion.

Effects of the anti-androgen finasteride on the modulatory actions of oestradiol on androgen metabolism by human gingival fibroblasts.

5 alpha-Reduction of androgen substrates results in the formation of the biologically active androgen 5 alpha-dihydrotestosterone (DHT), while 17 beta-hydroxysteroid dehydrogenase metabolises androgen substrates to 4-androstenedione or testosterone. The aim here was to study the effect of the anti-androgen finasteride on 5 alpha-reduction of androgens by human gingival fibroblasts (HGF) and its modulation by oestradiol-17 beta. Duplicate cultures of HGF were incubated with [14C]testosterone/[14C]4-androstenedione in Eagle minimum essential medium (n=6) in the presence or absence of oestradiol-17 beta (O) or finasteride (F; 0.1-3 microg/ml) for 24 h. The steroid metabolites were analysed and quantified using a radioisotope scanner. With [14C]testosterone as substrate, oestradiol stimulated the formation of DHT by 63% (n=6; P<0.01). In contrast, finasteride inhibited this activity by 61% (n=6; P<0.01). The combination of O+F produced 43% less inhibition than finasteride alone (n=6; P<0.01). There were 200-300% increases in the formation of 4-androstenedione in response to O and F, being less pronounced in combination. Oestradiol stimulated the formation of DHT from [14C]4-androstenedione by 300-600% and finasteride reduced the yield of DHT by 40-64%; there was less inhibition in combination with O. There were 300-700% increases in the formation of testosterone in response to F and O alone and in combination (n=6; P<0.01). Oestradiol-induced stimulation of 5 alpha-reductase activity on androgen substrates by HGF is suggestive of hormone modulatory mechanisms in the healing periodontium of both sexes. Its inhibition by finasteride is suggestive of type 2 isoenzyme activity, confirming target-tissue functions in the gingiva.

Effects of hormonal contraceptives on the periodontium, in a population of rural Sri-Lankan women.

AIMS: Women using hormonal contraceptives can be considered to be a 'risk group' for periodontal disease, due to prolonged, sustained serum levels of oestrogens and progesterone. This investigation aims to study the effects of hormonal contraceptives on periodontal tissues. METHODS: 32 women using hormonal contraceptives for less than 2 years, 17 for 2-4 years and a matched control group of 39 non-users were selected for the study. They were clinically examined for plaque levels (plaque index: PLI), gingival condition (gingival index: GI) and loss of periodontal attachment (LA). RESULTS: Contraceptive users of less than 2 years and 2-4 years duration (n=32, n= 17 respectively) and non-users (n=39) had similar oral hygiene levels; yet the contraceptive users had a significantly higher level of gingival inflammation, compared to the non-users (p<0.001; 1-way ANOVA). Usage of hormonal contraceptives for 2-4 years (n= 17) caused a significantly higher LA (p<0.001) compared to that of controls (n=39). CONCLUSIONS: Usage of contraceptive preparations containing oestrogen and progesterone resulted in hormonal changes similar to those seen in pregnancy, associated with increased prevalence of gingivitis. There was significantly higher LA with prolonged usage of hormonal contraceptives, compared with controls.

Periodontal disease status during pregnancy and 3 months post-partum, in a rural population of Sri-Lankan women.

OBJECTIVES: The aim of this investigation was to study the effects of pregnancy on the periodontium, in a rural population of Sri-Lankan women. METHODS: The study group consisted of 47 pregnant women and 47 non-pregnant women who served as matched controls. All subjects were examined for plaque (plaque index: PLI), gingival condition (gingival index: GI) and loss of periodontal attachment (LA) levels, 4 x during the study, at 3-monthly intervals. RESULTS: Despite similar scores for plaque levels in both pregnant and non-pregnant women, the GI of pregnant women was significantly increased, during the 1st and 2nd trimesters compared to the controls (p<0.01, 2-way ANOVA). During the 3rd trimester, GI was further increased (p<0.001), but dropped at 3 months post-partum. Values for LA did not show significant differences from that of controls, during any of the stages of pregnancy. CONCLUSIONS: The results of this study show that pregnancy had an effect only on the gingivae and not on periodontal attachment levels. The effects of oestrogen and progesterone could give rise to a more florid response to the irritant effects of plaque, resulting in severe gingivitis.

Effects of the anti-androgen finasteride on 5 alpha-reduction of androgens in the presence of progesterone in human gingival fibroblasts: modulatory actions of the alkaline phosphatase inhibitor levamisole.

Oestrogens and androgens stimulate collagen matrix synthesis, while progesterone is a competitive inhibitor for the 5 alpha-reduction of testosterone to 5 alpha-dihydrotestosterone (DHT). The anti-androgen finasteride is a specific inhibitor of the 5 alpha-reductase type 2 isoenzyme, associated with anabolic functions. The aim of this investigation is to study the effects of progesterone and finasteride on 5 alpha-reduction of androgen substrates by human gingival fibroblasts. Monolayer cultures of human gingival fibroblasts (HGF) of the 4th 9th passage were established in Eagle's minimum essential medium (MEM). Duplicate incubations were performed with 14C-testosterone/14C-4-androstenedione as substrates and progesterone (P) or finasteride (F), at concentrations of 0.5, 1, 3 and 5 microg/ml, alone and in combination, for 24 h. Similarly, the effects of the alkaline phosphatase inhibitor levamisole (L, 30 microg/ml) and P were studied. Steroid metabolites were analysed and quantified, using a radioisotope scanner. Progesterone inhibited DHT synthesis in HGF from 14C-testosterone by 24-62% (n = 8; p < 0.01). Finasteride caused 59 82% inhibition (n=8;p<0.01). The combination of P+F showed a similar degree of inhibition (68-78%) of DHT synthesis to that of F alone (n = 8; p<0.01). There was 35-56% stimulation of 17beta-HSD (hydroxysteroid dehydrogenase) activity by P, F and P + F (n = 8; p < 0.01). When 14C-4-androstenedione was used as substrate there was 47% inhibition of 5 alpha-reductase activity at higher concentrations of P and 63 and 44% stimulation at 0.5 and 1 microg/ml (n = 8;p < 0.01). F and P + F caused 40-67% inhibition of this activity. P, F and P + F caused 2-2.7-fold stimulation of 17beta-HSD activity in response to all concentrations studied. L inhibited DHT synthesis from both substrates by 36-38%, with further inhibition of 55-70% (n = 4; p < 0.01), with P; this is suggestive of ligand-independent alkaline phosphatase activity mediated by 5 alpha-reductase. Inhibition of 5 alpha-reductase activity by finasteride in gingival fibroblasts is suggestive of target tissue anabolic functions in gingivae and competitive inhibition by progesterone, is suggestive of regulation of hormone mediated tissue responses during repair.

The effect of minocycline on the metabolism of androgens by human oral periosteal fibroblasts and its inhibition by finasteride.

The antimicrobial minocycline has matrix-stimulatory effects on connective tissue and bone. The aim here was to study the effect of minocycline on 5alpha reduction of androgen substrates to 5alpha-dihydrotestosterone (DHT) in periosteal fibroblasts and the influence of the antiandrogen finasteride on this conversion. Confluent cultures of periosteal fibroblasts established from oral periosteum isolated from the bone surface were incubated in duplicate in multiwell dishes with two androgen substrates, [(14)C]-testosterone/[(14)C]-4-androstenedione, in the presence or absence of serial concentrations of minocycline or the antiandrogen finasteride or the two in combination for 24 h. The metabolites formed were solvent-extracted with ethyl acetate, separated by thin-layer chromatography and quantified using a radioisotope scanner. Both androgen substrates were metabolized to DHT and 4-androstenedione or testosterone. Minocycline stimulated the synthesis of DHT from these substrates by 75-83% at 20-30 microg/ml (n=4; p<0.01). Finasteride inhibited the 5alpha-reductase activity of these substrates by 3-5-fold at 1 microg/ml and 40-80% at 0.01 and 0.1 microg/ml (n=4; p<0.01), with little change in 17beta-hydroxysteroid dehydrogenase activity. Minocycline and finasteride in combination showed an intermediate response with one substrate. As finasteride inhibits the type 2, 5alpha-reductase isoenzyme associated with anabolic functions, these findings demonstrate target-tissue androgen metabolic activity in periosteal fibroblasts at baseline and in response to minocycline. This has implications for the reparatory potential of the diseased periodontium during adjunctive treatment with minocycline.

Androgen metabolism in response to oestradiol-17beta and progesterone in human gingival fibroblasts (HGF) in culture.

The modulation of androgen metabolism by oestrogen and progesterone in HGF has been investigated, to elucidate hormone modulatory mechanisms, in periodontal disease presentation and healing responses. Duplicate incubations of HGF were performed in Eagle's MEM for 24 h with either 14C-testosterone/14C-4-androstenedione as substrate and serial concentrations of oestradiol-17beta, or progesterone (0.01-50 microg/ml). The effect of the anti- oestrogen tamoxifen on the action of oestradiol in HGF was also investigated. The medium was analysed and quantified for steroid metabolites. When 14C-testosterone was used as substrate, oestradiol stimulated the synthesis of 5alpha-dihydrotestosterone (DHT), 4- androstenedione (4-A) and the diols by 35%, 25% and 2-10-fold respectively (n=4; p<0.01), at optimal concentrations. Tamoxifen inhibited the stimulatory effects of oestradiol. Similarly, when 14C-4-androstenedione was used as substrate, there were 60% and 2-fold increases in the yields of DHT and testosterone respectively, with significant increases in the formation of the diols in response to oestradiol (n=4; p<0.001). Progesterone inhibited the formation of DHT and 4-A by 10-fold and 3-5-fold at effective inhibitory concentrations (n=4; p<0.001), when 14C- testosterone was used as substrate. Similarly, when 14C-4-androstenedione was used as substrate, progesterone decreased the yields of testosterone, DHT and the diols substantially. These results reinforce the potentially anabolic and catabolic roles of oestradiol and progesterone, respectively. This may partly explain the modulatory mechanisms involved, in periodontal disease presentation during altered hormonal states and healing responses in the inflamed periodontium.

Modulation of androgen metabolism by estradiol-17beta and progesterone, alone and in combination, in human gingival fibroblasts in culture.

BACKGROUND: Androgens, particularly 5alpha-dihydrotestosterone (DHT), have anabolic effects on connective tissues and bone with implications on periodontal healing. This can be enhanced by estradiol-17beta (E-17beta), in synergy with androgen action. The effects of progesterone (P) contribute to plaque-induced inflammatory changes. The aim of this investigation was to study the modulation of androgen metabolism by E-17beta and P, alone and in combination. METHODS: Human gingival fibroblasts were established in monolayer culture and duplicate incubations were performed in Eagle's MEM for 24 hours with either 14C-testosterone (14C-T) or 14C-4-androstenedione (14C-4-A) as substrate and serial concentrations of E-17beta, P and E-17beta + P. The medium was solvent extracted for steroid metabolites, analyzed, and quantified using a radioisotope scanner. The androgen substrates were converted mainly to DHT and 4-androstenedione/testosterone from 14C-T and 14C-4-A respectively. RESULTS: At concentrations of 0.1 and 0.5 microg/ml, E-17beta stimulated DHT synthesis from 14C-T by 18% and 12%, respectively, decreasing to control values at 0.1 microg/ml. While the effect of similar concentrations of P on the same substrates was inhibitory by 18, 70, and 82% (n = 4; P <0.01). E-17beta + P showed a 12% increase in DHT synthesis over controls at 0.1 microg/ml, similar to that of E-17beta alone, despite the inhibitory effects of P (n = 4; P <0.01) with 12% and 77% decreases at 0.5 and 1 microg/ml (n = 4; P <0.01). The inhibitory effect of P on DHT synthesis was less apparent when E-17beta was present in combination. The formation of 4-androstenedione from 14C-T was stimulated by E-17beta (12.5%), inhibited by P (50%) and showed an intermediate response with E + P (33% stimulation). At the concentrations used, E-17beta stimulated DHT synthesis from 14C-4-A by 3.6-, 3- and 2.6-fold. P also stimulated this conversion from the same substrate by 16%, 2-fold, and 1.6-fold increases, partly due to the low yields at baseline. The combination of E + P stimulated the synthesis of DHT from 14C-4-A by 4-fold at 0.1 and 0.5 microg/ml and a 2.3-fold increase at 1 microg/ml. The formation of T from 14C-4-A was stimulated by E-17beta (50%) and inhibited by P (40%), with 93% stimulation by E + P at 0.1 microg/ml. CONCLUSIONS: The modulatory effects of estradiol-17beta and progesterone on androgen metabolism may influence disease presentation and the progress of healing responses in the inflamed periodontium.