Biomedical subjects

B Sato

Publications and source records attributed to B Sato.

At least 109 records · Page 6Linked to original sources

PubMed1987

Inhibitory and stimulatory effects of glucocorticoid on androgen-induced growth of murine Shionogi carcinoma 115 in vivo and in cell culture.

It has been generally accepted for 20 years that the growth of Shionogi carcinoma 115 (SC115) is stimulated only by androgen in vivo and in cell culture. However, we recently found that the growth of SC115 is also stimulated by pharmacological, but not physiological, doses of glucocorticoid both in vivo and in cell culture and by pharmacological doses of estrogen only in vivo. In the present study, therefore, we investigated the effect of dexamethasone on androgen-induced growth of SC115 cells in vivo and in cell culture. In a serum-free medium [Ham's F-12:Eagle's minimum essential medium (1:1, v/v) containing 0.1% bovine serum albumin], the proliferation of SC-3 cells (a cloned cell line from SC115 cells) estimated by cell number and DNA synthesis reached a plateau at 10(-8) M testosterone (up to 93-fold) or 10(-6) M dexamethasone (up to 7.2-fold); high stimulation induced by higher than 10(-8) M testosterone was inhibited by the addition of 10(-5)-10(-8) M dexamethasone in a concentration-dependent manner, whereas low stimulation induced by lower than 10(-10) M testosterone was significantly enhanced by the addition of dexamethasone. The presence of typical glucocorticoid and androgen receptors in SC-3 cells was also demonstrated; dexamethasone did not bind to androgen receptor and testosterone did not bind to glucocorticoid receptor. In castrated mice, the concomitant administration of dexamethasone again significantly inhibited the high growth of SC115 tumors induced by high doses of androgen but significantly enhanced the low growth induced by low doses of androgen. The present results demonstrate both inhibitory and stimulatory effects of glucocorticoid on androgen-induced proliferation of SC115 cells in cell culture and probably in vivo.

Animals↗

PubMed1987

Growth-stimulating effect of pharmacological doses of glucocorticoid on androgen-responsive Shionogi carcinoma 115 in vivo in mice and in cell culture.

It has been generally accepted for 20 years that the growth of Shionogi carcinoma 115 (SC115) is stimulated only by androgen. However, we recently found that the growth of SC115 cells is also stimulated by pharmacological doses of estrogen in vivo but not in cell culture. In the present study, the growth-stimulatory effect of glucocorticoid on SC115 cells was examined. In castrated mice, daily injections of high doses of dexamethasone (100 micrograms/mouse) markedly stimulated the tumor growth, and the growth approached that found in normal males. However, daily injections of physiological doses of dexamethasone (4 micrograms/mouse) or high doses of epitestosterone, progesterone, or cholesterol (200-5000 micrograms/mouse) did not enhance the tumor growth in castrated mice. The androgen dependency, growth speed, steroid receptors, and histological type of the tumors grown by pharmacological doses of glucocorticoid were not significantly different from those of the original SC115 tumors grown by androgen. In a serum-free medium [Ham's F-12:Eagle's minimum essential medium (1:1, v/v) containing 0.1% bovine serum albumin], the proliferation of SC-3 cells (a cloned cell line from SC115 cells) was markedly (by up to 25-fold) stimulated by 10(-10)-10(-8) M testosterone, whereas the proliferation was only slightly but significantly (by up to 3.3-fold) stimulated by 10(-8)-10(-5) M dexamethasone. The present findings demonstrate that the growth of SC115 cells in vivo and in cell culture is significantly stimulated by physiological doses of androgen or pharmacological doses of glucocorticoid.

Androgens↗

PubMed1987

Growth-stimulating effect of pharmacological doses of estrogen on androgen-dependent Shionogi carcinoma 115 in vivo but not in cell culture.

Shionogi carcinoma 115 (SC115) had been accepted for 20 years as an androgen-dependent mouse mammary tumor, the growth of which is stimulated only by androgen. However, we very recently found that the growth of SC115 tumors in vivo is stimulated not only by physiological doses of androgen but also by pharmacological doses of estrogen through the estrogen receptor system. In the present study, the growth-stimulative effect of estrogen on an androgen-dependent cloned cell line (SC-3) derived from SC115 cells, which showed androgen- and estrogen-dependent growth in vivo, was examined in vitro. In serum-supplemented medium (Eagle's minimum essential medium containing 2% steroid-free fetal calf serum), testosterone or 5 alpha-dihydrotestosterone (10(-9)-10(-6) M) significantly stimulated the growth of SC-3 cells (3.2-fold increase in cell number at day 10 in culture containing 10(-8) M androgens) and changed the shape of SC-3 cells from epithelial to spindle (fibroblast-like), whereas 17 beta-estradiol (10(-12)-10(-6) M) even in high concentrations had no such effects on SC-3 cells. Contrary to the effect of 17 beta-estradiol in vivo, 17 beta-estradiol as well as cyproterone acetate (10(-8)-10(-6) M) inhibited the growth-stimulative effect of testosterone (10(-8) M) on SC-3 cells in a dose-dependent manner in the serum-supplemented medium. The anti-androgen and 17 beta-estradiol also showed comparable competitive effects on [3H]testosterone binding to androgen receptor in SC-3 cells. In serum-free medium [Ham's F-12:Eagle's minimum essential medium (1:1, v/v) containing 0.2% bovine serum albumin], testosterone [10(-8) M] also markedly stimulated the growth of spindle-shaped SC-3 cells, and epidermal growth factor (1 ng/ml) enhanced the growth-stimulative effect of testosterone, whereas 17 beta-estradiol (10(-8)-10(-6) M) in the absence or presence of epidermal growth factor had no growth-stimulative effect on SC-3 cells. We conclude that the growth of SC115 cells is stimulated by either physiological doses of androgen or pharmacological doses of estrogen in vivo but only by androgen in cell culture.

Androgens↗

PubMed1987

Sodium molybdate converts the RNA-associated transformed, oligomeric form of the glucocorticoid receptor into the transformed, monomeric form.

The glucocorticoid receptor from rat liver cytosol prepared in 2 ml buffer/g tissue sedimented at approximately 10 S in low salt density gradient centrifugation without molybdate. When the receptor was heated at 25 degrees C, both approximately 10 S and approximately 7 S forms were seen in low salt gradient. The approximately 10 S form was not capable of binding to DNA-cellulose and was stabilized by sodium molybdate, namely it corresponded to untransformed receptor. The approximately 7 S form was capable of binding to DNA-cellulose and regarded as transformed receptor. On the other hand, partially-purified transformed receptor labeled with [3H]dexamethasone-21-mesylate sedimented at approximately 5 S, which migrated as a approximately 94 kDa species in SDS-polyacrylamide gel electrophoresis. The reconstitution analysis of this partially-purified approximately 5 S receptor and liver cytosol, showed the shift to approximately 7 S form. RNase A or T1 converted approximately 7 S transformed form into approximately 5 S but it did not affect approximately 10 S untransformed form. 5-20 mM sodium molybdate also shifted approximately 7 S to approximately 5 S. These results indicate that the approximately 7 S transformed form of the glucocorticoid receptor observed in low salt conditions might be an oligomer, probably including both approximately 5 S steroid-binding component and RNA/ribonucleoprotein, and that molybdate dissociates these interactions in a specific manner.

Adrenalectomy↗

PubMed1987

Biological and biochemical characterization of estrogen-dependent mouse Leydig cell tumors.

Leydig cell tumors formed in BALB/c mice were found to be able to be transplanted subcutaneously in the same strain. One of the sublines, called T 22137, showed growth inhibition in response to estrogenization of host mice. The other subline (T 124958-O), which was originally classified as an estrogen-independent line, was observed to contain the low-affinity estradiol binding component in the cytosol fraction. At a later stage of transplantation, however, the growth of this subline was modestly but significantly enhanced by estrogenic stimuli. This alteration was accompanied by appearance of an estrogen receptor-like molecule which was associated with chromatin even in the absence of estrogen stimuli. In the presence of estrogen selection pressure, a new tumor line, designated as T 124958-R, was established, which showed marked estrogen-dependent growth. T 124958-R was found to contain the cytosolic estrogen receptor. The additional difference was that the annulate lamellae were identified only in T 124958-R, but not in T 124958, by electron microscopic studies. The estrogen dependency of T 124958-R was further substantiated by demonstration of an estrogen secretory protein as well as the estrogen-enhanced formation of 5 alpha-steroids. T 22137 showed growth inhibition in tamoxifen-treated mice. The growth of T 124958-R was enhanced by the administration of tamoxifen to mice. This tamoxifen-induced tumor growth was further stimulated by the simultaneous administration of estrogen. These observations would suggest that mouse Leydig cell tumor systems provide us with a valuable model to investigate the influence of estrogen as well as antiestrogen on malignant cells.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed1987

Action mechanisms of physiological doses of androgen or pharmacological doses of estrogen in growth stimulation of Shionogi carcinoma 115 in mice.

Shionogi carcinoma 115 (SC115) had been accepted for 20 yr as an androgen-dependent mouse mammary tumor. However, we recently found that the growth of SC115 tumors in vivo is also stimulated by pharmacological doses of estrogen through estrogen receptor. In the present study, action mechanisms of androgen or high doses of estrogen in the growth stimulation of SC115 were examined using a cloned cell line (SC-3) derived from the SC115 tumor. In serum-supplemented [2% steroid-free fetal calf serum-Eagle's minimum essential medium (MEM)] and serum-free [HAM F-12: MEM (1:1, v/v) containing 0.1% bovine serum albumin] media, testosterone (Test, 10(-9)-10(-6) M) significantly increased both cell number and DNA synthesis of SC-3 cells (by up to 10-fold), whereas oestradiol-17 beta (10(-12)-10(-6) M) had no such effects; the Test-induced growth was completely inhibited by the addition of a 100-fold molar excess of cyproterone acetate (CA). The serum-free medium cultured with SC-3 cells in the presence or absence of 10(-8) M Test was collected [conditioned medium (CM) or conditioned medium without Test (CM-)], and then Test in CM was removed by Gel filtration using Sephadex G-100 or inactivated by the addition of a 100-fold molar excess of CA. In the serum-free culture system, the addition of the CM without Test activity significantly enhanced both number of SC-3 cells and DNA synthesis in the cells, whereas CM(-) had no such effects. The present findings suggest that growth-stimulatory activities of androgen and high doses of estrogen on SC115 cells are mediated by growth factor(s), secreted from SC115 cells through androgen receptor and from some of nontransformed cells through estrogen receptor, respectively.

Animals↗

PubMed1987

Leupeptin inhibits the transformation of glucocorticoid receptor.

The effect of leupeptin upon the transformation of the glucocorticoid receptor was tested. When the labeled receptor was treated with heat or high salt in the presence of leupeptin, the binding to DNA-cellulose decreased in a dose-dependent manner. We observed 50% inhibition with about 40 mM leupeptin. The addition of leupeptin after the transformation procedures did not inhibit the binding to DNA-cellulose. In gradient centrifugation, 40 mM leupeptin retained approximately 10S, untransformed form. Elution profiles from DEAE-cellulose showed the preservation of the peak eluted with 0.2 M KCl, corresponding to the untransformed form. These results indicate that leupeptin might have the similar effects to molybdate in regard to blocking the transformation of rat liver glucocorticoid receptor, though the effects with leupeptin were not as great as those seen with molybdate.

Adrenalectomy↗

PubMed1987

Effects of estrogen and vanadate on the proliferation of newly established transformed mouse Leydig cell line in vitro.

A permanent cell line (B-1-A-2) derived from an estrogen-responsive mouse Leydig cell tumor (T 124958-R) was established in culture. Although this cell line showed estrogen-induced enhancement of cell proliferation in vitro, a moderately high concentration (10(-8) M) of estradiol was required to stimulate maximum growth. A whole cell binding assay revealed that the B-1-A-2 cells contained estrogen receptors with relatively low affinity for estradiol (Kd, 10(-9)-10(-8) M). This estrogen receptor was found to have a mol wt of 65,000. In addition, incubation of the cells with [32P]orthophosphate and subsequent purification revealed that the estrogen receptor is phosphorylated. This finding prompted us to study the effect of phosphatase inhibitors on cell proliferation. The inclusion of vanadate (25 microM) in the culture medium resulted in a significant increase in estrogen sensitivity, showing a maximal growth stimulatory effect of estradiol at concentrations of 10(-10)-10(-9) M. Simultaneously, the conversion of the low affinity to the high affinity receptor (Kd, 10(-10)-10(-9) M) was induced by treatment of cells with vanadate. These data suggest that estrogen directly stimulates the growth of B-1-A-2 cells in culture, and that the sensitivity to estrogen can be altered by modulating the estrogen receptor possibly via a phosphorylation-dephosphorylation mechanism.

Animals↗

PubMed1987

A case of von Recklinghausen's disease associated with pheochromocytoma and papillary carcinoma of the thyroid gland.

A 58-year-old woman was admitted to our hospital complaining of headache, dizziness and intermittent elevation of blood pressure. Multiple café-au-lait spots and neurofibromas had appeared on the back and the limbs since the age of 30 years. At the age of 54 years she underwent total thyroidectomy because of papillary carcinoma of the thyroid gland. On admission, the levels of plasma norepinephrine and epinephrine, urinary norepinephrine and normetanephrine were all within the normal range. However, urinary excretion of metanephrine was markedly increased to 1.49 +/- 0.45 (Mean +/- SD) mg/day and that of epinephrine was also slightly increased. The computed tomographic scans of the abdomen and the scintigraphy with 131I-metaiodobenzylguanidine revealed a tumor mass in the region of the right adrenal gland. The tumor was histologically confirmed to be pheochromocytoma at the operation. In her family history, her mother and one of her two sisters had von Recklinghausen's disease and another sister suffered from follicular carcinoma of the thyroid gland. As far as we know, this paper is the first report of a patient with von Recklinghausen's disease associated with both pheochromocytoma and non-medullary carcinoma of the thyroid gland, and her family.

Carcinoma, Papillary↗

PubMed1987

Demonstration of specific dopamine receptors on human pituitary adenomas.

Dopamine receptors on human pituitary adenoma membranes were characterized using [3H] spiperone as the radioligand. The specific [3H]spiperone binding sites on prolactin (PRL)-secreting adenoma membranes were recognized as a dopamine receptor, based upon the data showing high affinity binding, saturability, specificity, temperature dependence, and reversibility. All of 14 PRL-secreting adenomas had high affinity dopamine receptors, with a dissociation constant (Kd) of 0.85 +/- 0.11 nmol/l (mean +/- SEM) and a maximal binding capacity (Bmax) of 428 +/- 48.6 fmol/mg protein. Among 14 growth hormone (GH)-secreting adenomas examined, 8 (57%) had dopamine receptors with a Kd of 1.90 +/- 0.47 nmol/l and a Bmax of 131 +/- 36.9 fmol/mg protein. Furthermore, 15 of 24 (58%) nonsecreting pituitary adenomas also had dopamine receptors with a Kd of 1.86 +/- 0.37 nmol/l and a Bmax of 162 +/- 26.0 fmol/mg protein. These results indicate that some GH-secreting adenomas as well as some nonsecreting pituitary adenomas contain dopamine receptors. But their affinity and number of binding sites are significantly lower (P less than 0.05) and fewer (P less than 0.001) respectively, than those in PRL-secreting adenomas.

Adenoma↗

PubMed1987

[Regulatory mechanism of steroid hormone receptor functions].

The steroid hormone receptor has been defined as an intracellular protein which associates with the corresponding ligand in a stereospecific manner. Its binding ability and affinity have been reported to be affected by many factors such as protein kinase, SH reducing agent and molybdate. Through ligand binding, hormone-receptor complexes undergo activation process resulting in its acquisition of high affinity toward DNA. Although the detailed biochemical mechanism of receptor activation remains to be elucidated, the reduction of their molecular size has been proposed to be an obligatory step for receptor activation. Recently, heat shock protein 90 K, has become known to bind with the oncogene product (pp 60 v-src). Furthermore, it has been demonstrated to be a common component of both nonactivated, and not activated steroid receptor. The recombinant gene technology has successfully determined the amino acid sequence of GR, ER and PgR. All steroid receptors consist of three domains, namely the immunogenic, DNA-binding and steroid-binding domains. Experiments using deletion mutant receptors revealed that the DNA binding domain has both abilities of DNA binding and transactivation, and that the steroid binding domain negatively regulates DNA binding activity. The purified GR has been found to bind with the specific region (GRE) of glucocorticoid-dependent genes. The consensus sequence of GRE has been observed to be TG-TTCT. Two other proteins which can be associated with some regions near GRE have been proposed to activate cooperatively the glucocorticoid responsive genes with GR. Therefore, the steroid hormone receptor systems are suitable for clarifying the molecular mechanism of gene activation.

Animals↗

PubMed1987

A case of virilizing adrenocortical carcinoma.

A 36-year-old woman who had experienced two pregnancies consulted our hospital, because of scant menses and virilization. A 24-hour excretion of 17-ketosteroids and 17-hydroxy-corticosteroids demonstrated a decrease in 11-hydroxylase. A computed tomogram showed a huge inhomogenous tumefaction in the left adrenal. Left selective renal angiography revealed a large adrenal tumefaction. Selective adrenal venous samplings revealed that testosterone and dehydroepiandrosterone (DHA) were produced in response to stimulation by 0.25 mg exogenous adrenocorticotropic hormone (ACTH). After left adrenalectomy was performed, a diagnosis of adrenocortical carcinoma was made by pathological examination. This is the first report of a patient with a virilizing adrenocortical carcinoma, which produced testosterone and DHA in response to exogenous ACTH stimulation.

17-Hydroxycorticosteroids↗

PubMed1987

Both androgen and glucocorticoid induce identical secretory proteins in serum-free culture of Shionogi carcinoma 115 cells.

The effects of androgen or glucocorticoid on the induction of secretory proteins in SC-3 cells (a cloned cell line from Shionogi carcinoma 115) were examined in a serum-free medium [Ham's F-12: Eagle's minimum essential medium (1:1, v/v) containing 0.1% bovine serum albumin]. Through analysis of [35S]methionine-labeled proteins by one-dimensional (sodium dodecyl sulfate polyacrylamide) gel electrophoresis, we successfully demonstrated the production of a testosterone (10(-9)-10(-6) M)- or dexamethasone (10(-8) M)-induced secretory protein with a molecular weight of 24,000 in SC-3 cells. However, 17 beta-estradiol (10(-8) M) or progesterone (10(-8) M) had no such effect. The production of the secretory 24K protein increased slightly within 2 hr after the addition of 10(-8) M testosterone and increased further thereafter. The addition of tunicamycin to the incubation mixture with [35S]methionine resulted in the identification of a testosterone- or dexamethasone-induced secretory protein with a molecular weight of 20,000. By the use of two-dimensional gel electrophoresis, we could demonstrate that both testosterone (10(-8) M) and dexamethasone (10(-8) M) added to the serum-free medium stimulate the secretion from SC-3 cells of the same 5 proteins (30-40K, 39K, 30K, 27K proteins and the secretory 24K glycoprotein). The present findings show that physiological concentrations of both androgen and glucocorticoid induce the secretion of the same 5 proteins from SC-3 cells.

Animals↗

PubMed1987

[Stimulation and inhibition of the growth of sex-steroid-dependent tumors].

Shionogi carcinoma 115 (SC 115) has been accepted for 20 years as a model androgen-dependent mouse mammary tumor. However, we recently found that the growth of SC 115 in vivo is also stimulated by large doses of estrogen via the estrogen receptor. In the present study, the action mechanisms involved in the growth stimulation of SC 115 were examined using a cloned cell line (SC-3) derived from the SC 115 tumor. In serum-supplemented (2% steroid-free FCS-MEM) and serum-free [HAM F-12: MEM (1:1, v/v) containing 0.1% BSA] media, testosterone (Test, 10(-9)-10(-6) M) markedly increased both the cell number and DNA synthesis of SC-3 cells (by up to 10-fold), whereas estradiol-17 beta (10(-12)-10(-6) M) had no such effects; the Test-induced growth was completely inhibited by the addition of a 100-fold excess of cyproterone acetate (CA). The serum-free medium cultured with SC-3 cells in the presence or absence of 10(-8) M Test was collected [conditioned medium (CM) or conditioned medium without Test (CM-)], and then Test in CM was inactivated by the addition of a 100-fold excess of CA. In the serum-free culture system, the addition of CM without Test activity significantly enhanced the proliferation of SC-3 cells, whereas CM (-) had no such effect. The present findings suggest that the growth-stimulatory activities of androgen and high doses of estrogen on SC 115 cells are mediated by growth factor (s), secreted from SC 115 cells via the androgen receptor and from some of the non-transformed cells via the estrogen receptor, respectively.

Androgens↗

PubMed1986

[Studies on estrogen receptor in normal and cancerous human uterine endometrium by immunological methods].

The presence of cytosol estrogen receptor (ER) and the ER of nuclear extracts in normal uterine endometrium and endometrial adenocarcinoma tissues were determined by radioreceptor assay (RRA) and enzyme immunoassay (EIA). In addition the intracellular localization of ER and tissue distribution of ER positive cells was demonstrated by immunocytochemical assay (ICA). The levels of cytosol ER measured by EIA and RRA had a significant correlation in normal endometrium (r = 0.90) (P less than 0.01) and endometrial adenocarcinoma (r = 0.96) (P less than 0.01) as well as in breast cancer (r = 0.93) (P less than 0.01). The ER measured by immunocytochemical method using the monoclonal anti-ER antibody obtained from breast cancer cells was applicable to the detection of the ER in uterine endometrial tissues. In endometrial adenocarcinoma, the levels of cytosol ER in G1 (Highly differentiated adenomatous carcinoma) tissues (187.6 +/- 189.0 fmoles/mg protein) were significantly higher than those in G2 (Moderately differentiated adenomatous carcinoma with partly solid areas) tissues (15.0 +/- 31.9 fmoles/mg protein) (P less than 0.05). The levels of cytosol ER peaked in the late follicular phase (432.0 fmoles/mg protein) and remained low in the other phases. Epithelial cells in the normal endometrium were stained uniformly by ICA, in contrast, ICA stained and non-stained cells existed concurrently in the same endometrial adenocarcinoma tissues. A similar finding was also shown in breast cancer tissues and may be related to the efficacy of anti-estrogenic drugs on the growth of whole cancer tissues.

Adenocarcinoma↗

PubMed1986

Impaired amylase activities caused by binding of abnormal immunoglobulin A in patients with macroamylasemia.

Eight of thirty analyzed samples of immunoglobulin A-linked macroamylases showed significantly higher enzyme activity with the low molecular (short-chain amylose) substrate than with the macromolecular (blue starch polymer) substrate. Immunoglobulin A, which had been separated from one macroamylase, was found to bind to normal amylases from different organs resulting in decreased affinity for the macromolecular substrate. These findings suggest that abnormal immunoglobulin A is stoichiometrically associated with a specific site adjacent to the active site of the amylase molecule. In addition, alpha-amylase inhibitor failed to inhibit the enzyme activity of some macroamylases with macromolecular substrate, suggesting that immunoglobulin A blocked the binding site for the inhibitor. We conclude that immunoglobulin A-linked macroamylases have heterogeneous binding sites for immunoglobulin A, resulting in functional abnormality of amylase activity.

Amylases↗

PubMed1986

Biochemical and immunological characterization of estrogen binding components in human neoplastic adrenocortical tissues.

The estrogen binding components in human adrenocortical tissues were examined. Two adrenocortical cancer cytosols were found to contain the binder with a relative low affinity (Kd 5 X 10(-9) M) for estradiol. The association of [3H]estradiol to these cytosols was inhibited by a large dose of unlabeled estrone, estradiol or estriol, but neither by diethylstilbestrol nor by dihydrotestosterone. Incubation of cultured cells derived from these cancers with [3H]estradiol also showed the presence of this low-affinity estradiol binder. The addition of bovine serum albumin into these cytosols surprisingly resulted in a marked increase in estradiol binding capacity in a concentration-dependent manner. This component sedimented at 5 S in the low salt sucrose density gradient. This binding ability was found to be heat-labile in the absence of estradiol, but preformation of complexes with estradiol markedly stabilized its binding ability against thermal inactivation. In addition, experiments using monoclonal antibodies to human estrogen receptor revealed that the estrogen binder from one adrenocortical cancer cytosol shared antigenic determinants with human estrogen receptor. These results suggest that the unique estrogen binder in some adrenocortical cancer has the characteristics similar to estrogen receptors in terms of thermal stability and immunological cross-reactivity to antibodies.

Adrenal Cortex Neoplasms↗

PubMed1986

Formation of 5 alpha-products as major C19-steroids in estrogen-responsive mouse Leydig cell tumor lines.

Homogenates of estrogen-responsive mouse Leydig cell tumors (T 124958-R and T 22137) or 28- and 120-day-old mouse testes were incubated with [3H]progesterone or [14C]4-androstene-3,17-dione in the presence of NADPH, and progesterone metabolism and enzyme activities were estimated. The growth of T 124958-R tumor transplanted in BALB/c mice was markedly stimulated by estrogenization of host mice, but the growth of T 22137 tumor was evidently suppressed by the estrogenization. The major C21-17-OH-steroids and C19-steroids formed from progesterone by both tumors and the testes of immature mice were 5 alpha-steroids, such as 3 alpha,17-dihydroxy-5 alpha-pregnan-20-one, 5 alpha-androstane-3,17-dione, androsterone, 3 beta-hydroxy-5 alpha-androstan-17-one and 5 alpha-androstane-3 alpha,17 beta-diol. In contrast, the major steroids formed by the testes of adult mice were testosterone and 4-androstene-3,17-dione, and no or little 5 alpha-steroids were produced. 5 alpha-Reductase activities in both tumor cells (40-50 nmol/l X 10(8) cells per h) were also found to be approx. 5-6 times higher than that in Leydig cells of adult mouse testes (8 nmol/l X 10(8) Leydig cells per h), though 17-hydroxylase activity was much higher in the Leydig cells of adult testes (730 nmol/l X 10(8) Leydig cells per h) than in both tumor cells (1-7 nmol/l X 10(8) cells per h). Furthermore, the presence of significant amounts of endogenous androsterone and/or 5 alpha-androstane-3 alpha,17 beta-diol was demonstrated in both tumors by radioimmunoassay. The present results demonstrate for the first time that C19-5 alpha-steroids are major C19-steroid products (immature type of testicular androgen production) in Leydig cell tumor lines.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗