Biomedical subjects

M Orava

Publications and source records attributed to M Orava.

At least 19 recordsLinked to original sources

PubMed2001

One versus two embryo transfer after IVF and ICSI: a randomized study.

BACKGROUND: The main reason for adverse treatment outcome in assisted reproduction is the high rate of multiple pregnancies. The only strategy to avoid dizygotic twins is to transfer one embryo at a time. METHODS: A total of 144 women, who had had at least four good quality embryos available after IVF/intracytoplasmic sperm injection (ICSI) and who had no more than one previous failed treatment cycle, were randomized to have either one or two embryos transferred. The treatment outcomes including those after frozen embryo transfer were compared between these groups. RESULTS: The clinical pregnancy rate per transfer was 32.4% in the one embryo transfer group and 47.1% in the two embryo transfer group, the difference being not significant. Eleven twin deliveries (n = 39) occurred in the two embryo transfer group and there was one pair of monozygotic twins in the one embryo transfer group. The cumulative pregnancy rate per patient after transfer of fresh and frozen embryos was 47.3% in the one embryo transfer group and 58.6% in the two embryo transfer group. CONCLUSIONS: Our results indicate that among women who have good quality embryos in their first IVF/ICSI, good treatment results can be achieved. They support the idea of changing embryo transfer policy towards one embryo transfer without any remarkable decrease in the success rate, while dizygotic twins can be avoided.

Adult↗

PubMed1998

Low pregnancy rate is achieved in patients treated with intracytoplasmic sperm injection due to previous low or failed fertilization in in-vitro fertilization.

The main indications for intracytoplasmic sperm injection (ICSI) are severe male factor and fertilization failure or a low fertilization rate in previous in-vitro fertilization (IVF) treatments. The fertilization and pregnancy rates after ICSI, however, are seldom reported separately for these two different indications. The aim of this study was to compare the treatment outcome and pregnancy rate after ICSI between 65 patients with previous failed fertilization or a low fertilization rate without male factor, and 219 patients with a primary male factor. From the 2726 oocytes collected, 2087 (77%) were micro-injected and 1355 (65%) achieved normal fertilization. The oocyte fertilization rate was similar in the group with previous failed fertilization or a low fertilization rate and the group with a male factor (65 and 65% respectively), as was the cleavage rate of normally fertilized oocytes (92 and 94% respectively). Despite the similar fertilization and cleavage rates and the similar number and morphological quality of embryos transferred in both groups, the pregnancy rate was significantly lower (P < 0.05) in the group with previous failed fertilization or a low fertilization rate than in the group with a male factor (19.6 versus 33.5% respectively; 95% confidence intervals for the difference, 2-26%). The implantation rate was also lower (P = 0.01) in patients with previous failed fertilization or a low fertilization rate (9.6%) than in the group with a male factor (19.5%). We conclude that patients with previous failed fertilization or a low fertilization rate in standard IVF without male factor have a significantly smaller chance of becoming pregnant after subsequent ICSI than patients with a primary male factor. This poor outcome probably reflects intrinsic oocyte defects not bypassed by ICSI.

Adult↗

PubMed1996

Molecular cloning of mouse 17 beta-hydroxysteroid dehydrogenase type 1 and characterization of enzyme activity.

The biological activity of certain estrogens and androgens is modulated by enzymes called 17 beta-hydroxysteroid dehydrogenases (17 beta-HSDs), which catalyze the interconversion between less active 17-oxosteroid and more active 17 beta-hydroxysteroid forms. In the present report, we describe cloning of mouse 17 beta-HSD type-1 cDNA from an ovarian library generated from 4,4'-(1,2-diethyl-1,2-ethenediyl)bisphenol-(diethylstilbestrol)-tr eated mice, and characterization of the corresponding enzyme. The open reading frame of the mouse 17 beta-HSD type-1 cDNA encodes a peptide of 344 amino acid residues with a predicted molecular mass of 36785 Da. The mouse 17 beta-HSD type-1 enzyme shares 63% and 93% overall identity with human and rat 17 beta-HSD type-1 enzymes, respectively, and the most striking differences between the mouse and human type-1 enzymes are between the amino acid residues 197 and 230 and in the carboxy terminus of the enzymes. Similarly to the human 17 beta-HSD type-1 enzyme, the mouse type-1 enzyme primarily catalyzes reductive reactions from 17-oxo forms to 17 beta-hydroxy forms in intact cultured cells, but unlike the human type-1 enzyme, the mouse enzyme does not prefer phenolic over neutral substrates. Thus, mouse 17 beta-HSD type 1 catalyzes reduction of androst-4-ene-3,17-dione (androstenedione) to 17 beta-hydroxyandrost-4-en-3-one (testosterone) as efficiently as 3 beta-hydroxyestra-1,3,5(10)-trien-17-one (estrone) to estra-1,3,5(10)-triene-3 beta, 17 beta-diol (estradiol). 17 beta-HSD type 1 is predominantly expressed in mouse ovaries, in which it is located in granulosa cells.

17-Hydroxysteroid Dehydrogenases↗

PubMed1995

Serum and urinary steroids in girls with precocious pubarche and/or hirsutism due to mild 3-beta-hydroxysteroid dehydrogenase deficiency.

To obtain data on the correlation of serum and urinary steroids in nonclassical 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency, 9 girls with precocious pubarche and 33 adolescent girls with mild to severe hirsutism were studied. Urinary steroid profiles were analyzed by capillary gas chromatography. Serum 17-OH-pregnenolone (17-OHPreg) and 17-OH-progesterone (17-OHP) were determined by RIA after column-chromatographic separation. One out of 9 girls with precocious pubarche and 4/33 girls with hirsutism had elevated ratios of 17-OHPreg to 17-OHP after ACTH stimulation in serum and elevated urinary excretion of 5-ene steroids under basal conditions. These patients were defined to have decreased adrenal 3 beta-HSD activity. Basal and ACTH-stimulated serum 17-OHPreg levels in patients with mild 3 beta-HSD deficiency overlapped those of healthy controls and peripubertally virilized female patients without enzyme deficiency. Post-ACTH 17-OHPreg/17-OHP ratios in serum discriminated patients with and without 3 beta-HSD deficiency using a cutoff value of 13 instead of mean + 2 SD for age-related control values (6.7 and 11.6 for girls with Tanner stage II-III and IV-V, respectively). Sums of urinary 5-ene steroids in patients with 3 beta-HSD deficiency overlapped those in patients without enzyme deficiency. Results showed that an abnormal post-ACTH serum 17-OHPreg/17-OHP ratio may not be associated with elevated urinary 5-ene steroid excretion, and vica versa. In conclusion, patients with simultaneous elevation of post-ACTH serum 17-OHPreg/17-OHP ratio and basal urinary 5-ene steroid excretion are supposed to have mild 3 beta-HSD deficiency.

17-alpha-Hydroxyprogesterone↗

PubMed1994

Structure and chromosomal location of the gene encoding mouse corticosteroid-binding globulin: strain differences in coding sequence and steroid-binding activity.

Corticosteroid-binding globulin (CBG) is a member of the serine proteinase inhibitor superfamily and is responsible for the plasma transport of glucocorticoids. The mouse Cbg gene structure has been deduced from two non-overlapping DNA fragments of a lambda EMBL-3 genomic library, as well as PCR amplification of the approx. 2 kb of genomic DNA that lies between them. Mouse Cbg comprises five exons that span a region of approx. 10.5 kb, and has been localized in tight linkage with the Aat (alpha 1-antitrypsin) and Spi (serine proteinase inhibitor) gene complex on chromosome 12, in a region syntenic with this genetic locus on human chromosome 14. Intron-specific oligodeoxyribonucleotide primers were also used to PCR-amplify Cbg coding regions from several mouse strains. No differences were found in the Cbg coding sequences of BALB/c and C57BL/6J-cpk/cpk mice, while two mutations were found within RIIIS/J Cbg that result in Lys201-->Glu and Ala357-->Thr substitutions in the mature mouse CBG polypeptide. To assess what impact these substitutions might have on the steroid-binding activity of RIIIS/J CBG, these mutations were introduced separately or together into a BALB/c mouse Cbg cDNA. Expression of these mutants in the MDCK cell line indicated that the Lys201-->Glu substitution accounts for the abnormal steroid-binding affinity of CBG in RIIIS/J mice.

Amino Acid Sequence↗

PubMed1994

Serum distribution of two contraceptive progestins: 3-ketodesogestrel and gestodene.

A cross-over study of two oral contraceptive formulations, containing 30 micrograms ethinylestradiol in combination with 150 micrograms desogestrel (Marvelon) or 75 micrograms gestodene (Femovan), has been performed to compare the serum distribution and pharmacokinetics of gestodene and the active metabolite of desogestrel, namely 3-ketodesogestrel. Serum concentrations of both sex hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG) were also measured and were increased more than 3-fold and 2-fold, respectively, on day 21 of the treatment cycle, with no statistically significant difference between treatment groups. In addition, 35 days after ingestion of either oral contraceptive had ceased, the serum SHBG and CBG concentrations were similar to the pretreatment values. During treatment cycles, increased serum SHBG levels were associated with a redistribution of 3-ketodesogestrel and gestodene such that the non-protein-bound (NPB) and albumin-bound fractions were reduced in concert with an increase in the relative proportions bound to SHBG. The proportion of gestodene bound to SHBG was consistently higher than that observed for 3-ketodesogestrel, and this undoubtedly reflects the higher affinity of SHBG for gestodene (Kd = 1.2 nM at 37 degrees C) when compared to 3-ketodesogestrel (Kd = 4.7 nM at 37 degrees C). It also probably accounts, in part, for the much higher total serum levels of gestodene (8.58 nmol/L) when compared to 3-ketodesogestrel (2.37 nmol/L) during the treatment cycles. Consequently, the absolute amounts of NPB, non-SHBG-bound, and SHBG-bound gestodene are significantly higher than those measured for 3-ketodesogestrel. It is concluded that ethinylestradiol-induced increases in serum SHBG levels during treatment with Marvelon or Femovan, influenced the distribution and total amount of 3-ketodesogestrel and gestodene in serum, respectively, and that this, combined with the higher affinity of SHBG for gestodene, results in a greater amount of bioavailable gestodene compared to 3-ketodesogestrel, despite the smaller dose of gestodene administered.

Adult↗

PubMed1994

Characterization of 17 beta-hydroxysteroid dehydrogenase type 1 in choriocarcinoma cells: regulation by basic fibroblast growth factor.

17 beta-Hydroxysteroid dehydrogenase type 1 (17-HSD type 1) is a steroidogenic enzyme catalyzing reversible interconversion of estradiol and estrone. 17-HSD type 1 is actively expressed in human placenta. We characterized 17-HSD type 1 expression and its regulation by basic fibroblast growth factor (bFGF) in JAR, JEG-3 and BeWo choriocarcinoma cell lines. Based on Southern and Northern analysis, as well as measurement of catalytic activity and immunoreactive protein, all the choriocarcinoma cell lines contained and expressed the gene coding for 17-HSD type 1, identical to that of normal human cells. However, the cell lines showed marked quantitative differences in the levels of expression of the enzyme, being lowest in JAR cells and highest in BeWo cells, as measured by immunofluorometric assay, Northern analysis and catalytic activity. These differences in the basal level of expression were most probably not based on any sequence differences in the putative proximal promoter area of the gene in different cell lines, since no dissimilarities were observed in the 806 bp region upstream from the transcription start site of 1.3 kb mRNA coding for 17-HSD type 1 except for frequent polymorphism characteristic of normal human cells using polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) analysis. The reductive (estrone-->estradiol) activity was about 4-7 times higher compared with the oxidative activity (estradiol-->estrone) in all the cell lines studied, indicating that in these choriocarcinoma cell lines, 17-HSD activity favours estradiol formation.(ABSTRACT TRUNCATED AT 250 WORDS)

17-Hydroxysteroid Dehydrogenases↗

PubMed1994

Rat 17 beta-hydroxysteroid dehydrogenase type 1: primary structure and regulation of enzyme expression in rat ovary by diethylstilbestrol and gonadotropins in vivo.

17 beta-Hydroxysteroid dehydrogenase (17HSD) catalyzes the reversible conversion of estrone into estradiol. The complementary DNA (cDNA) coding for rat 17HSD type 1 was cloned from a commercial rat ovarian cDNA library, using human 17HSD type 1 cDNA as a probe. The nucleotide sequence extends for 1160 basepairs (bp), including 1035 bp of open reading frame, a stop codon, and 125 bp of 3'-untranslated sequence. The cDNA encodes a protein of 344 amino acids, with a calculated molecular mass of 36,967 daltons. The overall amino acid identity and similarity between rat and human 17HSD type 1 enzymes are 68% and 80%, respectively. Immunohistochemistry and in situ and Northern hybridizations were used to study regulation of the enzyme in rat ovary in vivo. Enzyme expression was detected in granulosa cells only, whereas no expression was observed in stromal or thecal cells. The enzyme was almost undetectable in ovaries from immature hypophysectomized rats. After 2-day treatment with recombinant FSH (recFSH), an induction of 17HSD type 1 expression was observed in granulosa cells of growing antral follicles. During 5 days of diethylstilbestrol (DES) treatment, a time-dependent increase in developing follicles was observed, showing strong expression of 17HSD type 1 in granulosa cells. Treatment with recFSH for 2 days in DES-primed animals resulted in down-regulation of ovarian enzyme expression. This reduction of enzyme expression was associated with luteinization of the follicles. hCG treatment of recFSH- or DES- plus recFSH-primed animals further induced luteinization, resulting in strong down-regulation of 17HSD type 1 expression. The enzyme was not detected in corpora lutea. The data show that 17HSD type 1 expression in rat ovary is regulated by gonadotropins and estrogens. The results suggest that expression of 17HSD type 1 and that of cytochrome P450 aromatase are regulated by distinct mechanisms, and 17HSD type 1 may be down-regulated earlier than P450 aromatase during luteinization, limiting estradiol biosynthesis in luteinizing granulosa cells in rat ovary.

17-Hydroxysteroid Dehydrogenases↗

PubMed1994

Regulation of 17 beta-hydroxysteroid dehydrogenase type 1 by epidermal growth factor and transforming growth factor-alpha in choriocarcinoma cells.

17 beta-Hydroxysteroid dehydrogenase type 1 (17HSD type 1) is a steroidogenic enzyme that catalyzes the reversible interconversion of estrone and estradiol. In this study, we investigated the roles of epidermal growth factor (EGF) and tumor growth factor-alpha (TGF alpha) in the regulation of 17HSD type 1 gene expression and catalytic activity in cultured JAR, JEG-3, and BeWo choriocarcinoma cells. EGF and TGF alpha increased 17HSD type 1 protein concentrations in JAR and JEG-3 cells, as measured by time-resolved immunofluorometric assay, and 17HSD catalytic activity, as determined by production of estradiol from estrone. These increases were accompanied by parallel increases in concentrations of the 1.3-kilobase messenger RNA coding for 17HSD type 1 in these cells. EGF receptor tyrosine kinase activity inhibitors, tyrphostins, inhibited EGF action in JEG-3 cells, indicating that tyrosine kinase activity is needed for stimulation of the 17HSD type 1 gene. Treatment with 8-bromo-cAMP or phorbol 12-myristate 13-acetate increased the amount of 17HSD type 1 protein. Furthermore, phorbol 12-myristate 13-acetate potentiated the stimulatory effect of EGF. These results suggest that EGF and/or TGF alpha may play an important role in 17HSD type 1 regulation and, consequently, in estrogen production in the human placenta.

17-Hydroxysteroid Dehydrogenases↗

PubMed1993

Spatial and temporal distribution of corticosteroid-binding globulin and its messenger ribonucleic acid in embryonic and fetal mice.

Glucocorticoids influence fetal development, and their actions are regulated by plasma corticosteroid-binding globulin (CBG). Immunohistochemistry and in situ hybridization were, therefore, used to localize CBG and its mRNA in sections of embryonic and fetal mice and their associated placental tissues from day 5 of gestation until term (day 19). In the fetus, CBG mRNA was first detectable in the hepatocytes on day 11 of gestation. The amount of CBG mRNA in these cells increased transiently to a maximum on days 15-16 of gestation and was negligible by day 19. In hepatocytes, CBG immunoreactivity correlated with the distribution and relative abundance of CBG mRNA. The fetal exocrine pancreas also contained CBG mRNA, but this was only present on days 15-16 of gestation, while immunoreactive CBG persisted in these cells until term. Immunoreactive CBG was detected in the tubular cells of the developing fetal kidney as early as day 13, but CBG mRNA was never found in the fetal kidney, suggesting that the protein is probably sequestered from fetal blood directly or via the glomerular filtrate. The placenta contained immunoreactive CBG throughout gestation, even before its detection in fetal tissues, and it was most abundant in the spongiotrophoblasts and the extracellular matrix surrounding fetal and maternal capillaries. However, CBG mRNA was not detected in the placenta at any gestational age. Therefore, CBG present in the placenta is most likely of maternal origin and may influence the activities of steroid hormones that control placental development and/or function. The presence of smaller immunoreactive polypeptides in placental extracts, compared to CBG in corresponding maternal serum samples, suggests that this process may involve an interaction between maternal CBG and placental proteinases. The results presented here suggest that temporal and spatial changes in the localization of CBG and its mRNA in the fetus may influence the effects of steroid hormones on developing tissues.

Amino Acid Sequence↗

PubMed1992

Effect of growth hormone administration on human ovarian function and steroidogenic gene expression in granulosa-luteal cells.

OBJECTIVE: To study the effect of growth hormone (GH) in combination with an ultrashort-term gonadotropin-releasing hormone analogue/human menopausal gonadotropin (hMG)/human chorionic gonadotropin (hCG) regimen in ovarian hyperstimulation for in vitro fertilization (IVF). DESIGN: Prospective randomized placebo-controlled study. SETTING: University-based IVF program. PATIENTS: Fifty-four normally cycling women (27 control and 27 GH-treated) participated in this study. INTERVENTIONS: Human recombinant GH (24 IU)/placebo was given intramuscularly on alternate days starting on cycle day 4 until the day of last hMG injection. RESULTS: Serum estradiol (E2) and progesterone (P) concentrations were slightly lower in the GH group than in the placebo group on the day of hCG injection and 1 day thereafter (P < 0.01 to 0.001). Serum luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone (T), and sex hormone-binding globulin did not differ between the groups. The follicular fluid (FF) concentration of T was higher in the GH group than in the placebo group (15.9 +/- 6.0 nmol/L versus 10.2 +/- 4.9 nmol/L, P < 0.005), and no differences were observed in the FF concentrations of E2, P, and insulin-like growth factor I between the groups. In granulosa cells isolated from patients who received GH treatment, the levels of 3 beta-hydroxysteroid dehydrogenase and aromatase messenger ribonucleic acid were significantly higher than in the patients receiving placebo. The number of hMG ampules needed for follicular development and the number of follicles and oocytes recovered were similar in both groups. CONCLUSIONS: These results indicate that GH administration modifies ovarian steroidogenic response to gonadotropins in IVF patients, suggesting a role for GH in the regulation of human ovarian function.

Adult↗

PubMed1991

Regulation of steroid and steroid sulfate production and aromatase activity in cultured human granulosa-luteal cells.

The regulation of the production of steroids and steroid sulfates and the activity of aromatase in human luteinized granulosa cells were investigated. The cells were cultured for 48 h in the presence or absence of hCG and FSH. Basal production of pregnenolone (Pre, 0.3 +/- 0.03 ng/micrograms protein) and progesterone (P, 19.3 +/- 1.7 ng/micrograms protein) were high compared with that of other steroids beyond P in the steroidogenic pathway. The concentration of 17 alpha-hydroxyprogesterone (17-OHP) was lower 0.17 +/- 0.06 ng/micrograms and that of other steroids in the 4-ene and 5-ene pathways and steroid sulfates less than 0.05 ng/micrograms. Both hCG and FSH (100 ng/ml) stimulated the production of Pre and P 3- to 5-fold, but only minimal stimulation of other steroids and steroid sulfates was observed. Aromatase activity of granulosa-luteal cells was measured from the rate of formation of 3H2O from 1 beta-[3H]androstenedione (1 beta[3H]A) after exposing the cells to hCG, FSH or estradiol (E2) for 48 h. Basal aromatase activity was relatively low, but hCG and FSH stimulated aromatase 8- and 4-fold, respectively. The incubation of granulosa-luteal cells with E2 did not affect basal aromatase activity, but E2 augmented FSH-stimulated aromatase 1.4-fold (P less than 0.025). The results suggest that there is low 17 alpha-hydroxylase and steroid sulfokinase activity in human granulosa-luteal cells. Aromatase activity in these cells is regulated by both hCG and FSH, and intra-ovarian estrogens may regulate granulosa cell aromatase activity.

Aromatase↗

PubMed1990

Endocrine responses to gonadotrophins after LHRH agonist administration on cycle days 1-4: prevention of premature luteinization.

A treatment regime comprising an intranasally administered luteinizing hormone-releasing hormone (LHRH) agonist analogue (buserelin) on cycle days 1-4, followed by gonadotrophin administration [follicle stimulating hormone (FSH)/human menopausal gonadotrophin (HMG)] resulted in identical oestradiol (E2) responses compared with the reference method using clomiphene citrate (CC) and gonadotrophins. Immediately after analogue administration (day 4), buserelin-treated women showed short-lived elevations in serum LH and progesterone concentrations, but in the later follicular phase, the serum LH concentration was lowered compared with the controls. None of the women treated with analogue displayed elevated serum LH or progesterone concentrations at the time of injection of human chorionic gonadotrophin. In the early luteal phase, these women had higher serum levels of progesterone and higher progesterone to E2 ratios than the controls, but the length of the luteal phase was slightly shortened. Hence, in hyperstimulated cycles, 4-day treatment with buserelin caused profound endocrinological changes: namely, short-term rescue of the corpus luteum, prevention of an endogenous LH rise and premature luteinization and increased progesterone production in the early luteal phase.

Adult↗

PubMed1989

Steroid sulfates in testis tissue of prostatic cancer patients treated for six months with the gonadotropin releasing hormone agonist buserelin.

In order to assess the extent of inhibition of testicular steroidogenesis during long-term treatment of prostatic cancer with GnRH agonist, we measured the intratesticular levels of 5 steroid sulfate conjugates in human testis tissue removed from patients after 6 months of intranasal treatment with buserelin. The most pronounced decreases were found in testosterone and pregnenolone sulfates, to 1.6 and 7.1%, respectively, of concentrations measured in testis tissue from primarily orchiectomized prostatic cancer patients. In contrast, clearly smaller decreases were found in three other steroid sulfates measured, those of dehydroepiandrosterone (to 26%), 17-hydroxyprogesterone (to 27%) and 5-androstene-3 beta, 17 beta-diol (to 62%). These results are in keeping with our previous analyses of unconjugated steroids in similar tissue samples, and indicate that testicular steroidogenesis per se is not totally blocked by long-term intranasal treatment with GnRH agonist. Testicular steroid sulfate conjugation may be specifically suppressed since the total concentration of these conjugates decreased more than free steroid levels in our earlier measurements.

Aged↗

PubMed1989

Prolactin suppression by bromocriptine stimulates aromatization of testosterone to estradiol in women.

The effect of follicular phase bromocriptine therapy on the ovarian endocrine response to clomiphene citrate and gonadotropins was studied in 35 tubal infertility patients in a randomized placebo-controlled trial. During bromocriptine treatment, the serum prolactin (PRL) concentration significantly decreased, and consequently the serum estradiol (E2) concentration was significantly higher than in the controls on cycle day 9, and the ratio of testosterone (T) to E2 was decreased from cycle day 8 through day 10. The luteal phase progesterone concentration and the length of the luteal phase were not affected by bromocriptine therapy. The number and quality of oocytes harvested and the cleavage rates were similar in both groups. The present results, together with our previous observations, demonstrate that PRL participates in the regulation of ovarian steroidogenesis, particularly aromatization of T to E2.

Adult↗

PubMed1989

Comparison of the inhibitory effects of interferons-alpha and -gamma on testosterone production in porcine Leydig cell culture.

In porcine Leydig cell culture, incubation with natural or recombinant human interferon-alpha (IFN-alpha), or recombinant porcine IFN-gamma preparations were effective in inhibiting basal and human chorionic gonadotropin (hCG)-stimulated testosterone production in a dose-dependent manner. Combined treatment with any of the human IFN-alpha preparations plus recombinant porcine IFN-gamma at the maximal inhibitory dose (1,000 pmoles/liter) further increased the inhibitory effect of any single IFN preparation on hCG-stimulated testosterone production. These results show that in porcine Leydig cells, both human IFN-alpha and porcine IFN-gamma are able to inhibit testosterone production and that the inhibitory action can be enhanced significantly by combined treatment with these types of IFNs. The enhancement of the inhibitory effect by combined treatment is consistent with the known presence of distinct cell membrane receptors for IFN-alpha and IFN-gamma.

Animals↗

PubMed1989

Interferon-gamma inhibits steroidogenesis and accumulation of mRNA of the steroidogenic enzymes P450scc and P450c17 in cultured porcine Leydig cells.

The inhibitory effects of recombinant porcine interferon-gamma (IFN gamma) on human CG (hCG)-stimulated testosterone production, and on mRNA concentrations of cholesterol side-chain cleavage (P450scc) and 17 alpha-hydroxylase/C17-20lyase (P450c 17) were investigated using porcine primary Leydig cell culture as a model. After preincubation of Leydig cells for 24 h with 1000 pM IFN gamma, hCG-stimulated (10 ng/ml, 2 h) testosterone production was inhibited by 50%, whereas no significant changes were seen in hCG-stimulated cAMP production. Incubation with 10 microM 5-cholestene-3 beta,22(R)-diol or 10 microM 5-cholestene-3 beta,20 alpha-diol together with hCG (10 ng/ml, 2 h) reversed most of the inhibitory effect of IFN gamma, suggesting that IFN gamma inhibits P450scc activity, possibly by inhibiting the substrate (cholesterol) availability for P450scc. Incubation with IFN gamma also decreased basal concentrations of P450scc (45%) and P450c 17 (35%) mRNA, although these changes probably did not contribute to the decreased testosterone production. Long-term treatment with hCG (100 ng/ml, 24 h) increased P450scc mRNA (3- to 4-fold) and P450c 17 mRNA (4- to 5-fold) concentrations. Simultaneous treatment with IFN gamma attenuated these hCG-induced increases in P450scc mRNA (50%) and P450c 17 mRNA (40-100%) concentrations, as well as in testosterone production (77%). This inhibition of testosterone production could only be partly reversed by the hydroxylated cholesterol derivatives. This suggests that in addition to possible suppression of cholesterol availability, decreased P450scc and/or P450c 17 activities (through decreased mRNA concentrations) were also involved in the IFN gamma suppressed steroidogenic capacity of porcine Leydig cells during long-term hCG stimulation.

Animals↗

PubMed1987

Metoclopramide-induced hyperprolactinaemia: effects on corpus luteum function, endometrial steroid receptor concentrations and 17 beta-hydroxysteroid dehydrogenase activity.

Induced hyperprolactinaemia impairs ovarian follicular development, especially during the recruitment period. The consequences of hyperprolactinaemia during the luteal phase alone on corpus luteum function have not been characterized, nor have the actions of excessive circulating PRL on the endometrium. In this study, postovulatory 5-d administration of metoclopramide (MC) increased serum concentrations of PRL and decreased those of pregnenolone and progesterone indicating inhibition of steroidogenesis in the corpus luteum. This effect may partly explain the relatively common failure of implantation in association with induced ovulation using regimens leading to transient hyperprolactinaemia. In contrast to this, MC-induced hyperprolactinaemia during the mid-follicular (4 d) or early luteal phase of the cycle did not alter the concentrations of cytosol or nuclear oestrogen and progestin receptors or the activity of 17 beta-hydroxysteroid dehydrogenase in endometrial tissue. Thus, transiently elevated circulating PRL does not seem to have direct effects on female sex steroid receptors or their function in the proliferative or secretory endometrium.

17-Hydroxysteroid Dehydrogenases↗