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Biomedical subjects

F Labrie

Publications and source records attributed to F Labrie.

At least 397 records · Page 22Linked to original sources
PubMed1988

Androgenic activity of dehydroepiandrosterone and androstenedione in the rat ventral prostate.

In order to assess the androgenic potency of physiological plasma concentrations of the adrenal steroids dehydroepiandrosterone (DHEA) and androstenedione (delta 4-dione) in the rat prostate, these two steroids were released from Silastic tubings of appropriate length and size in castrated male rats. Implants of DHEA led to plasma levels of DHEA and 5-androsten-3 beta,17 beta-diol covering the range of concentrations found in adult men while no significant change was observed in plasma levels of delta 4-dione, testosterone and dihydrotestosterone (DHT). delta 4-Dione implants, on the other hand, led to a parallel increase in plasma delta 4-dione and testosterone levels at all doses used while plasma DHT only increased at supraphysiological doses of delta 4-dione. At plasma concentrations comparable to those found in adult men; delta 4-dione (0.8 ng/ml) and DHEA (3.4 ng/ml) stimulated prostate weight 3.7- and 2.1-fold, respectively. In the same groups, prostatic DHT levels were elevated at 4.48 +/- 0.05 and 2.70 +/- 0.73 ng/g tissue, respectively. A close parallelism was observed between prostatic DHT levels and prostatic weight in all groups. The present data show that in the rat, a species having no significant secretion of adrenal androgens, plasma concentrations of DHEA and delta 4-dione maintained within the range of those found in adult men are efficiently converted into DHT and act as potent androgenic stimuli in prostatic tissue. The castrated rat bearing Silastic implants releasing constant and predetermined amounts of adrenal steroids offers a good model to study the recently identified role of adrenal steroids in peripheral tissues.

Androgens↗
PubMed1988

Mediation by the androgen receptor of the stimulatory and antiandrogenic actions of 17 beta-estradiol on the growth of androgen-sensitive Shionogi mammary carcinoma cells in culture.

Increasing concentrations of 17 beta-estradiol (E2) led to a maximal 7-fold stimulation of growth of the highly androgen-sensitive clone (SEM-1) of the mammary carcinoma Shionogi cell line. Half-maximal stimulation by the estrogen was observed at 100 nM E2. Diethylstilbestrol (DES), on the other hand, a synthetic estrogen with no affinity for the androgen receptor, had no significant stimulatory effect on cell growth but caused growth inhibition at concentrations above 1 microM. Mediation of the action of E2 by the androgen receptor is indicated by the absence of interference of E2 action by the antiestrogen LY156758 while the antiandrogen hydroxyflutamide (3 microM) caused a 50% inhibition of E2 action. While increasing concentrations of E2 led to a progressive increase in cell growth, a progressive shift in the ED50 value of action of dihydrotestosterone (DHT) was observed at intermediate (10-100 nM) concentrations of E2 while 10 microM E2 completely inhibited DHT action. At those high E2 concentrations, however, E2 itself led to a stimulation of cell growth equivalent to approximately 50% of the maximal value achieved by DHT. E2 competed with the specific uptake of [3H]testosterone in intact cells at an inhibition constant (Ki) value of 15 nM, thus indicating direct interaction of E2 with the androgen receptor. Preincubation with E2 had no influence on the apparent affinity of testosterone for the androgen receptor nor on the number of androgen binding sites. The present data demonstrate that both the stimulatory and antiandrogenic action of E2 on the growth of the androgen-sensitive mammary carcinoma cell line SEM-1 are mediated through direct interaction of the estrogen with the androgen receptor. Such data may offer an explanation for the subjective improvements reported in prostate cancer patients receiving a high dose of E2 when relapsing after castration.

Androgen Antagonists↗
PubMed1988

Changes in plasma lipoproteins during various androgen suppression therapies in men with prostatic carcinoma: effects of orchiectomy, estrogen, and combination treatment with luteinizing hormone-releasing hormone agonist and flutamide.

Cardiovascular complications are a well recognized side-effect of antihormonal therapy in men with prostatic carcinoma. We studied changes in plasma lipoproteins in patients with prostate cancer during treatment with several androgen suppression therapies. Estrogen, orchiectomy, and a combination of LHRH agonist and antiandrogen (flutamide) reduced plasma testosterone concentrations (89-92%) and plasma estradiol decreased by 85%, 44%, and 54%, respectively. Estrogen induced hypertriglyceridemia and elevation of plasma HDL cholesterol, phospholipid, and apolipoprotein A-I and A-II concentrations. Low density lipoprotein (LDL) cholesterol decreased but LDL apolipoprotein B did not. These results suggest that the cardiovascular complications that occur during estrogen administration are not mediated through changes in lipoprotein profile, other than the hypertriglyceridemic effect. Orchiectomy caused hypercholesterolemia and an increase in both total and LDL apolipoprotein B, all of which are strong determinants of cardiovascular disease. The high density lipoprotein (HDL) concentration was not affected despite a reduction in plasma testosterone, perhaps due to a simultaneous decrease in estradiol. Combination therapy had no effect on plasma lipid and apolipoprotein B concentrations, but very low density lipoprotein (VLDL) apolipoprotein B decreased, and LDL apolipoprotein B increased. The HDL cholesterol and apolipoprotein A-I concentrations increased but A-II and phospholipids did not. These results suggest enhanced lipoprotein lipase activity, consistent with the reciprocal changes in VLDL and LDL apolipoprotein B levels, apolipoprotein B enrichment of LDL particles, and increase in HDL cholesterol. The higher apolipoprotein A-I to A-II ratio indicates an increase in HDL2 subfraction due to inhibition of endothelial hepatic lipase, increased secretion of apolipoprotein A-I, or both. These effects are attributed to estradiol, which decreased less than after orchiectomy, and to additional adrenal androgen inhibition by flutamide. We conclude that estradiol plays an important role in determining plasma lipoprotein concentrations in men, and androgens exert an antagonist effect. The lipoprotein profile resulting from the combination treatment is more beneficial than that resulting from orchiectomy or estrogen administration.

Aged↗
PubMed1988

Effect of luteinizing hormone releasing hormone (LHRH) and [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide on alpha-subunit and LH beta messenger ribonucleic acid levels in rat anterior pituitary cells in culture.

The effect of incubation with LHRH and its agonist [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide has been measured on the concentrations of mRNAs for the common alpha-subunit of glycoprotein hormones and beta-LH in rat anterior pituitary cells in primary culture. After incubation, total RNA was analyzed by Northern blot or dot blot hybridization with alpha- and LH beta 32P-labeled cRNA probes and mRNA levels were quantified by autoradiography. Short-term treatment (4-6 h) of pituitary cells with 100 nM LHRH led to a marked stimulation of LH release but no effect was observed on alpha-subunit or LH beta mRNA levels. Longer (24-72 h) incubation periods with LHRH led to complete desensitization of the LH response to the neurohormone and induced 2- to 3-fold increases in alpha-mRNA cell content while LH beta mRNA levels remained unchanged. Maximal induction of alpha mRNA accumulation was observed with an LHRH concentration as low as 0.1 nM. Incubation with the LHRH agonist [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide for 24-72 h also increased alpha mRNA but did not modify LH-beta mRNA levels. It is concluded that long-term exposure of anterior pituitary cells to LHRH or to an LHRH agonist positively regulates alpha-subunit gene expression in the absence of change in LH beta mRNA levels. This observation can provide an explanation for the high plasma levels of free alpha-subunits found in patients treated chronically with LHRH agonists.

Animals↗
PubMed1988

Modulation by sex steroids and [D-Trp6, Des-Gly-NH2(10)]luteinizing hormone (LH)-releasing hormone ethylamide of alpha-subunit and LH beta messenger ribonucleic acid levels in the rat anterior pituitary gland.

LHRH and sex steroids play a major and direct regulatory role in the secretion of LH by the anterior pituitary gland. The aim of the present study was to investigate the interactions between sex steroids, more especially the potentiating effect of progesterone (P) in the presence or absence of a low dose of 17 beta-estradiol (E2) and/or dihydrotestosterone (D) on mRNA levels encoding the alpha- and beta-subunits of LH in both female and male rats. We also studied the effect of 2-week treatment with the LHRH agonist [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide on the same parameters. After treatment with the LHRH agonist (5 micrograms daily), the accumulation of mRNA encoding the alpha-subunit was stimulated by approximately 3-fold while the LH beta mRNA concentration remained unchanged. Ovariectomy performed 14 days earlier, increased pituitary alpha and LH beta mRNA levels by 3.7- and 8.8-fold, respectively, while orchiectomy performed 14 days earlier increased alpha and LH beta mRNA levels by 6- and 6.5-fold, respectively. The present data demonstrate that although P alone exerts no effect on alpha and LH beta mRNA levels in castrated animals, treatment with P markedly potentiates the inhibitory effect of E2 on both mRNA levels in female as well as male rats. In addition, P potentiates the inhibitory effect of D on LH beta mRNA levels in castrated female rats. Furthermore, the present study illustrates the importance of the cumulative inhibitory effects of relatively low doses of E2 and D on mRNAs encoding both LH subunits. Moreover, the present observation of a differential modulation of alpha-subunit and LH beta mRNA levels after chronic treatment with an LHRH agonist offers an explanation for the high plasma levels of free alpha-subunit found in patients treated with LHRH agonists.

Animals↗
PubMed1988

Effects of sex steroids on regulation of the levels of C1 peptide of rat prostatic steroid-binding protein mRNA evaluated by in-situ hybridization.

Prostatic steroid-binding protein (PBP) is the most abundant protein synthesized in the rat ventral prostate. The protein is under strict androgenic control and is made of two subunits containing the polypeptides C1, C2 and C3. Using an 35S-labelled cDNA probe, we have used quantitative in-situ hybridization to assess the regulation of polypeptide C1 mRNA levels by sex steroids in the adult male rat. Densitometric quantification of autoradiographic hybridization signals revealed that a significant decrease in C1 mRNA levels could be detected 5 h after castration. Levels of C1 mRNA decreased by 50% 2.5 days after castration, while undetectable levels were reached within 7 days. Administration of the potent androgen 5 alpha-dihydrotestosterone to castrated rats caused a progressive increase in C1 mRNA levels which became significant 5 h after the first injection, while prolonged treatment, for 3 and 7 days, caused 50 and 100% reversals respectively of the effect of castration on C1 mRNA levels. Similar results were obtained by dot-blot hybridization using the same 32P-labelled cDNA probe, thus confirming the specificity and quantification achieved by in-situ hybridization. Administration of oestradiol-17 beta to orchiectomized adult rats for 14 days had no effect on steady-state C1 mRNA levels. Progesterone, on the other hand, at the dose used (2 mg twice daily) caused a marked increase in C1 mRNA levels, measured by in-situ hybridization, which was completely reversed by concomitant administration of the pure antiandrogen flutamide. The present data clearly demonstrate that the expression of PBP C1 peptide mRNA is under strict androgenic control and is a very sensitive and specific parameter of androgenic activity. They also indicate that quantitative in-situ hybridization is a powerful, sensitive and most efficient tool to study the regulation of gene expression while, in addition, providing precise information about the site of mRNA localization as well as information about the histology of the tissue, particularly the heterogeneous nature of the acinar response to androgenic stimulation and deprivation.

Androgen-Binding Protein↗
PubMed1988

Endocrine effects of combined treatment with an LHRH agonist in association with flutamide in metastatic prostatic carcinoma.

The plasma levels of pituitary hormones (LH, FSH and prolactin) as well as testosterone were determined in 62 patients treated with combined therapy using the LHRH agonist [D-Trp6, des-Gly-NH2(10)]LHRH ethylamide and the antiandrogen Flutamide. Plasma radioimmunoassayable LH and FSH levels increased to 534% (p less than 0.01) and 150% (p less than 0.01) of control, respectively, during the first 5 days of treatment, while, afterwards, a marked inhibition was observed which remained constant at approximately 30-50% of control values during the whole period of treatment. All patients showed a decrease of plasma testosterone concentration to approximately 10% of control levels. Detailed determinations of plasma testicular and adrenal steroid levels were then performed in 15 patients. Our data indicate that, except for the blockade of testicular 17-hydroxyprogesterone secretion, the combined therapy has no effect on plasma C-21 steroid levels. However, adrenal C-19 steroids, namely dehydroepiandrosterone and its sulfate, androst-5-ene-3 beta, 17 beta-diol and androstenedione were decreased to approximately 50% of control values (p less than or equal to 0.01). The main testicular steroids, testosterone and dihydrotestosterone, which were increased during the first 10 days of combined administration, rapidly decreased and reached approximately 10% of control values at later time intervals. The present study extends our previous observations indicating that the combined antihormonal treatment affects both testicular and adrenal steroidogenesis. Moreover, we have demonstrated that, up to at least 2 years, this treatment, in addition to decreasing the serum levels of testicular androgens, causes an inhibition of the plasma levels of C-19 steroids from adrenal origin.

Adenocarcinoma↗
PubMed1988

Combination therapy with flutamide and castration (orchiectomy or LHRH agonist): the minimal endocrine therapy in both untreated and previously treated patients with advanced prostate cancer.

One hundred fifty-four patients with clinical stage D2 prostate cancer with no previous endocrine therapy or chemotherapy received the combination therapy with the pure antiandrogen Flutamide and the LHRH agonist [D-Trp]LHRH ethylamide for an average of 22 months (3 to 49). The objective response to the treatment was assessed according to the criteria of the US NPCP. There was a 6.3-fold increase (29.2 versus 4.6%) in the percentage of patients who achieved a complete response as compared to the results achieved in 5 recent studies limited to removal (orchiectomy) or blockade (DES or Leuprolide) of testicular androgens. Only 4.5% of patients did not respond to the combination therapy as compared to an average of 18% by standard therapy. The duration of response is also significantly increased in the patients who received the combination therapy while the death rate was decreased by approximately 2-fold between 2 and 3 years of treatment. The marked (6.3-fold) improvement in the rate of complete objective responses coupled with the 4-fold decrease in the number of non responders, the increased duration of the positive responses and the 2-fold decrease in the death rate at 2 to 3 years of treatment are obtained with the combination therapy using Flutamide and castration with no or minimal secondary effects. In addition, two hundred nine patients with biopsy-proven stage D2 prostatic adenocarcinoma showing disease progression after orchiectomy, DES or an LHRH agonist used alone received the combination therapy with the pure antiandrogen Flutamide. In patients treated with DES, the estrogen was replaced by the LHRH agonist [D-Trp6]LHRH ethylamide. Objective response to therapy was also assessed according to the criteria of the US NPCP. Thirteen patients (6.2%) had a complete response to treatment while partial and stable responses were achieved in 20 (9.6%) and 39 (18.7%) patients, respectively, for a total objective response rate of 34.5%. The mean duration of response was 24 months. While, in the non responders, the median survival was 8.13 months with a 17% probability of survival at 2 years, the probability of survival of patients who showed partial and stable responses at 2 years was 87 and 67%, respectively. All patients who achieved a complete response are still alive. Considering the excellent tolerance coupled with an objective response observed in 34.5% of the patients, the combination therapy with Flutamide and castration (surgical or LHRH agonist) appears to be the treatment of choice for prostate cancer patients in relapse after standard endocrine therapy.

Adenocarcinoma↗
PubMed1987

Development of androgen resistance in mouse mammary tumor cells can be prevented by the antiandrogen flutamide.

As has been clearly demonstrated in prostate and breast cancer, progression to hormone insensitivity is a major problem responsible for the usually partial and short-lived response to antihormonal therapy. Preincubation of androgen-sensitive Shionogi mouse carcinoma cells for 15 days in the absence of androgens causes the development of complete resistance of cell growth to androgens. Of potentially important therapeutic significance is the finding that androgen sensitivity can be maintained not only by the androgen dihydrotestosterone (DHT) but also by incubation with the pure antiandrogen Flutamide-OH in the absence of androgens. Since androgen resistance is one of the main problems facing the treatment of prostate cancer, the possibility of avoiding or at least delaying the development of androgen resistance with a pure antiandrogen could well provide the basis for improving the success of therapy for this disease.

Anilides↗
PubMed1987

Combination therapy in stage C and D prostatic cancer: rationale and five year clinical experience.

In 1941, Huggins and his colleagues discovered that testicular androgens exert a stimulatory effect on prostate cancer growth. Our group has made the key observations that the human adrenals, in addition to the tests, also secrete important amounts of androgens and cancer cells exhibit a marked heterogeneity of androgen sensitivity. In fact, human adrenals secrete large amounts of precursor steroids that are converted into active androgens in peripheral tissues (including the prostate), thus providing 40% to 50% of total androgens in adult men. The action of these androgens remaining after castration can be inhibited in prostatic cancer tissue by administering a pure antiandrogen that also decreases the local concentration of dihydrotestosterone (DHT). The castration levels of serum testosterone left in men after castration have an important stimulatory activity on the growth of androgen-sensitive normal as well as cancer tissues. Cancer cells have markedly different requirements for androgens. Some cell clones can grow in the presence of minimal amounts of androgens, requiring more complete androgen blockade and more potent antiandrogens for inhibiting growth. Among the compounds recommended as antiandrogens, the most unexpected finding is that many of them are devoid of any antiandrogenic activity. In fact, medroxyprogesterone acetate, chlormadinone acetate, and megestrol acetate have androgenic activity, but do not inhibit the peripheral action of DHT in prostatic tissue. These compounds should not be classified as antiandrogens. Cyproterone acetate, on the other hand, is a mixed agonist-antagonist. The only compounds showing pure antiandrogenic activity are Flutamide and its analogues. There is thus a need for a more complete blockade of androgens of both testicular and adrenal origins in order to exert a maximal inhibitory effect on cancer growth. We have therefore performed clinical studies in previously untreated stage D2 and C prostate cancer patients with the combination therapy using the LHRH agonist [D-Trp6, des Gly NH2(10)] LHRH ethylamide and the antiandrogen Flutamide. There was a significant increase in patients with a complete response, as compared with studies limited to the removal or blockade of testicular androgens. There was also a significant decrease in the number of non-responders, an increased duration of positive response, and a decrease in the death rate. This was achieved with minimal or no side effects, thus preserving a good quality of life.

Adrenal Glands↗
PubMed1987

Adrenal C19-5-ene steroids induce full estrogenic responses in rat pituitary gonadotrophs.

Previous studies have shown that the C19 adrenal steroid 5-androstene-3 beta, 17 beta-diol (5-ene-diol), a metabolite of dehydroepiandrosterone (DHEA), can stimulate typical estrogenic responses in target tissues. Since estrogens are known to cause a specific stimulatory effect on LHRH-induced LH release in rat anterior pituitary cells in culture, we have taken advantage of the precision of this system to study the effect of 5-ene-diol or DHEA on this precise estrogen-sensitive parameter. Pretreatment for 48 h with 17 beta-estradiol (E2), 5-ene-diol or DHEA induces a 2.4-, 2.7- and 2.6-fold stimulation of LH release induced by 0.3 nM LHRH, the effect being exerted at respective 50% maximally effective concentrations (ED50 values) of 0.015, 45 and 115 nM. Following a 48-h preincubation with 10 nM E2, 1 microM 5-ene-diol or 1 microM DHEA, the maximal LH and FSH responses to LHRH are increased by approx 50% above control. On the other hand, the sensitivities of the LH and FSH responses to LHRH as assessed by ED50 values of LHRH action are increased by 3.3- to 7.5-fold. As further proof of the estrogenic nature of the effect of 5-ene-diol and DHEA, the effects of E2, 5-ene-diol and DHEA are inhibited competitively by simultaneous incubation with the antiestrogen LY156758 (keoxifene). The 2-fold stimulation of LHRH-induced LH release caused by DHEA-S, at concentrations within the range found in the plasma of women, is also completely blocked by 120 nM LY156758. In direct binding studies, 5-ene-diol and DHEA or DHEA-S have approx 85- and greater than 10,000 lower affinities than E2, respectively, for the estrogen receptor in rat anterior pituitary homogenate and human breast carcinoma cytosol. The present data clearly show that 5-ene-diol, DHEA and DHEA-S can exert full estrogenic activity in rat gonadotrophs, thus supporting the potential estrogenic role of these C19 adrenal steroids in estrogen-dependent processes, especially breast cancer.

Androstenediol↗
PubMed1987

Combination therapy with flutamide and castration (orchiectomy or LHRH agonist): the minimal endocrine therapy in both untreated and previously treated patients.

Patients (154) with clinical stage D2 prostate cancer with no previous endocrine therapy or chemotherapy received the combination therapy with the pure antiandrogen Flutamide and the LHRH agonist [D-Trp6]LHRH ethylamide for an average of 22 months (3-49 months). The objective response to the treatment was assessed according to the criteria of the US NPCP. There was a 6.3-fold increase (29.2 vs 4.6%) in the percentage of patients who achieved a complete response as compared to the results achieved in five recent studies limited to removal (orchiectomy) or blockade (DES or Leuprolide) of testicular androgens. Only 4.5% of patients did not respond to the combination therapy as compared to an average of 18% by standard therapy. The duration of response is also significantly increased in the patients who received the combination therapy. The death rate was decreased by approximately 2-fold between 2 and 3 yr of treatment. The marked (6.3-fold) improvement in the rate of complete objective responses coupled with the 4-fold decrease in the number of non-responders, the increased duration of the positive responses and the 2-fold decrease in the death rate at 2-3 yr of treatment are obtained with the combination therapy using Flutamide and castration with no or minimal secondary effects.

Adenocarcinoma↗
PubMed1987

Effects of flutamide and aminoglutethimide on plasma 5 alpha-reduced steroid glucuronide concentrations in castrated patients with cancer of the prostate.

Plasma levels of androstane-3 alpha, 17 beta-diol glucuronide (3 alpha-diol-G) and androsterone glucuronide (ADT-G) have been found to be effective markers of C-19 steroid metabolism in periphery in man. The present study has been performed in order to study in castrated patients the effect of antiandrogen administered alone or in combination with aminoglutethimide (AG) on the metabolism of adrenal C-19 steroid. Ten castrated patients with prostatic cancer received flutamide (FLU) alone for 2 months and, afterwards, the combined therapy of FLU and AG for 2 months. Antiandrogen treatment alone reduces the levels of dehydroepiandrosterone sulfate (DHEA-S), dehydroepiandrosterone glucuronide (DHEA-G) and androstenedione (4-ene-dione) by 43, 34 and 38% (P less than or equal to 0.01) respectively while dehydroepiandrosterone (DHEA), androst-5-ene-3 beta,17 beta-diol (5-ene-diol) and androst-5-ene-3 beta,17 beta-diol-glucuronide (5-ene-diol-G) levels show a nonsignificant inhibition. In these patients, plasma 3 alpha-diol-G and ADT-G concentrations are nonsignificantly stimulated to 122 and 143%. Moreover, when patients were receiving the combined administration of FLU and AG, adrenal C-19 steroids were further inhibited while both 3 alpha-diol-G and ADT-G show a small but nonsignificant decrease. Our data indicate that the antiandrogen increases the formation and/or the metabolism of adrenal C-19 steroids into steroid glucuronides.

Aged↗
PubMed1987

Analysis of the androgenic activity of synthetic "progestins" currently used for the treatment of prostate cancer.

In order to assess the androgenic activity of synthetic "progestins" currently used as "antiandrogens" for the treatment of prostate cancer in men, the effect of a series of these compounds has been measured following 14 days of treatment of adult castrated rats on specific and sensitive parameters of androgenic activity, namely ventral prostate weight and prostatic ornithine decarboxylase (ODC) activity. Medroxyprogesterone acetate (MPA) is almost equipotent with 5 alpha-dihydrotestosterone (DHT), a 49% increase in prostatic weight being observed at the low dose of 0.15 mg, twice daily (P less than 0.01). Megestrol acetate (Megace), chlormadinone acetate (CMA) and spironolactone were less potent but caused a 36-59% increase in prostatic weight at the highest dose used, namely 10 mg. At the 5 mg dose, cyproterone acetate (CPA) caused a 75% increase in prostatic weight. The androgenic activity of the compounds is even more clearly illustrated by their marked stimulatory effect on prostatic ornithine decarboxylase (ODC) activity. MPA, at the low dose of 0.15 mg, caused a 20-fold increase (relative to the effect of placebo) in the activity of the enzyme while the same dose of DHT caused a 15-fold stimulation of enzymatic activity. At the 10 mg dose, megestrol acetate, CMA and spironolactone caused 13.1, 11.8 and 8.6-fold stimulations of ODC activity, respectively. Flutamide, on the other hand, had no stimulatory effect on either ventral prostate weight or prostatic ODC activity. In agreement with glucocorticoid activity, MPA, megestrol acetate and CMA caused a marked inhibition (45-64%) of adrenal weight. The present data show that MPA is a highly potent androgen while megestrol acetate, CMA, CPA and spironolactone have lower but significant androgenic activity on all the parameters measured. It should be added that MPA, megestrol acetate and CMA are completely devoid of antiandrogenic activity while spironolactone shows weak antiandrogen action and CPA is a mixed agonist-antagonist. Flutamide, the compound used as reference, is the only compound devoid of any androgenic action and is thus acting as a pure antiandrogen on both ventral prostate weight and prostatic ODC activity. The present data have major implications for the choice of drug to be used for the treatment of androgen-sensitive diseases, especially prostate cancer. As shown by the present data, the synthetic "progestins" so-far available all possess variable levels of androgenic activity and are thus not recommended for the treatment of prostate cancer.

Adrenal Glands↗
PubMed1987

Increase in plasma high-density lipoprotein concentration following complete androgen blockage in men with prostatic carcinoma.

There is evidence that endogenous estrogens have a positive effect on plasma high density lipoprotein (HDL) concentration, whereas the relation between HDL and male sex hormones is unclear, since both positive and negative effects have been reported. This study examined the effects of LHRH agonist in combination with an antiandrogen on plasma lipids and lipoproteins in 17 elderly men with prostatic carcinoma. Subjects were examined prior to and after therapy at 4-week intervals up to 16 weeks. Prior to therapy, their lipid and lipoprotein profiles were not significantly different from a control group composed of individuals of similar age and living in the same community area. Following therapy plasma levels of testosterone and dihydrotestosterone were markedly decreased (above 90%) and their residual activity neutralized through effective use of an antiandrogen. Plasma estradiol decreased between 65% and 85% and the concentration of cortisol was unaffected. The very low density lipoprotein (VLDL) apo-B decreased and low density lipoprotein (LDL) apo-B increased; thus, no change was observed in the total plasma apo-B levels. Total plasma cholesterol increased by 6% (baseline v peak values, mg/dL, mean +/- SEM; 219 +/- 9 v 233 +/- 9, P less than 0.05) due to a significant rise in HDL cholesterol concentration (45.5 +/- 2.8 v 56.5 +/- 3.6, P less than 0.01). Both VLDL and LDL cholesterol levels remained unchanged. The mean elevation of 21% in HDL cholesterol was accompanied by a significant rise in HDL apo-A concentration (161 +/- 6 v 193 +/- 10, P less than 0.01), thus suggesting an increase in HDL mass and/or particle number.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1987

Flutamide eliminates the risk of disease flare in prostatic cancer patients treated with a luteinizing hormone-releasing hormone agonist.

Although chronic treatment with luteinizing hormone-releasing hormone agonists achieves castration levels without side effects other than those related to hypoandrogenism, a limitation to their use alone for the treatment of prostatic cancer is the transient increase in serum androgens that lasts for 5 to 8 days at the start of treatment with the risk of disease flare. Our data show that the concomitant administration of the pure antiandrogen flutamide in association with the luteinizing hormone-releasing hormone agonist (D-Trp6) luteinizing hormone-releasing hormone ethylamide caused a 64 to 78 per cent decrease in serum prostatic acid phosphatase on days 3 and 7 after the start of treatment in 70 patients with previously untreated stage D2 prostatic cancer. Pain, which was present in 41 patients at the start of treatment, did not increase in any patient, it decreased in 7 at 1 week and it disappeared or decreased in 27 at 2 weeks. Performance, which originally was abnormal in 34 patients, became normal in 7 within 1 week and in 20 within 1 month (59 per cent). These data show that the addition of flutamide completely eliminates the risks of disease flare associated with the use of the otherwise exceptionally well tolerated luteinizing hormone-releasing hormone agonists in patients treated for prostatic cancer.

Acid Phosphatase↗
PubMed1987

Characteristics of radioimmunoassays for the alpha- and beta-subunits of human luteinizing hormone.

The binding characteristics and specificities of the National Hormone and Pituitary Program (NHPP) kits for the radioimmunoassay of the alpha- and beta-subunits of human luteinizing hormone (hLH-alpha and hLH-beta) were studied, as well as the specificities of the anti-hLH and anti-human follicle stimulating hormone (anti-hFSH) antisera distributed by the same organization. The affinity constants of the anti-hLH-alpha and anti-hLH-beta antisera were calculated at 157 +/- 8.4 nM-1 and 109 +/- 7.4 nM-1, respectively. Both antisera were highly specific with regard to the other subunit. However, in the homologous hLH-alpha RIA, native hLH cross-reacted at 21.9%, hFSH at 17.5% and hTSH at 7.9%. The alpha-subunit of the human chorionic gonadotropin, hCG-alpha, was equipotent with the hLH-alpha standard in this assay. In the homologous hLH-beta RIA, hLH showed a cross-reactivity of 14.7% while the cross-reactivities of hCG-beta, hFSH and hTSH were 3.5%, 1.2% and 0.6%, respectively. The anti-hFSH antiserum was highly specific, while the anti-hLH antiserum showed non parallel competition curves. With this knowledge of the specificity of each antiserum, corrections can be properly made for the assays of hLH, hLH-alpha and hLH-beta while the hFSH RIA can be used without correction for the presence of the three other components.

Antibody Specificity↗