Stimulation of rat testis microsomal 17alpha-hydroxyprogesterone side-chain cleavage enzyme by luteinizing hormone added in vitro.
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ABSTRACT:
SUBMITTER: Hagerman DD
PROVIDER: S-EPMC1198433 | biostudies-other | 1967 Dec
REPOSITORIES: biostudies-other
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Project description:The action of a luliberin (luteinizing-hormone-releasing hormone) agonist (ICI 118630) and lutropin (luteinizing hormone) on the activity of the cytochrome P-450 cholesterol side-chain cleavage enzyme in rat Leydig cells has been investigated. This has been carried out by studying the metabolism of exogenous (22R)-22- and 25-hydroxycholesterol to testosterone. It was found that both hydroxycholesterols increased testosterone production to higher levels than achieved by lutropin alone. Addition of luliberin agonist but not lutropin was found to increase further the metabolism of the hydroxycholesterol to testosterone; this occurred in the presence of saturating and subsaturating levels of the hydroxycholesterols. This effect of luliberin agonist was potentiated in the presence of lutropin. The protein synthesis inhibitor, cycloheximide, inhibited the luliberin agonist-induced stimulation of the hydroxycholesterol metabolism. At low calcium levels (1.1 microM), testosterone production was increased by addition of (22R)-22-hydroxycholesterol but the luliberin agonist effect was negated. The calmodulin inhibitor trifluoperazine inhibited (22R)-22-hydroxycholesterol-stimulated steroidogenesis and negated the luliberin agonist effect. These results indicate that luliberin agonist specifically increases the synthesis of the cytochrome P-450 cholesterol side-chain cleavage enzyme in rat testis Leydig cells.
| S-EPMC1152570 | biostudies-other
Project description:Gonadotropins are heterodimers consisting an alpha chain (Cgα) and a beta chain. Interestingly, presence of complicated LH-β transcripts in rat testis was accidently found; testicular LH-β transcripts were confined in seminiferous tubules to spermatids, and the translated products were localized in the elongated spermatids. We hypothesized that mouse testis has potential to produce the tissue specific LH-β with similar structure to the rat testicular forms. To verify our hypothesis, we examined the adult mouse (ICR) testis using RT-PCR and immunohistochemistry. The PCR revealed the presence of the identical products in the reactions for three LH subunit types. The expected product sizes for mouse Cgα and LH-β known as pituitary type were 224 bp and 503 bp, respectively. The testicular type LH-β products were produced by a primer set based on the rat sequences, with unexpected size of 800 bp. Sequencing revealed that the proximal and distal parts (2-82 and 661- 773 bp, respectively) were homologous to rat testicular LH-β cDNA, and middle part (83-660 bp) was a unique mouse-specific region. Both Cgα and LH-β positive signals were in the round and elongated spermatids and mature sperms, and the LH-β signals were more intense. In conclusion, our study demonstrated that the presence and localization of the LH subunits in mouse testis. Further studies will be needed to understand the precise structure and function of mouse testicular LH.
| S-EPMC5651699 | biostudies-literature
Project description:Gonadotrophin-releasing hormone (GNRH1) regulates pituitary luteinizing hormone (LH). Previous studies have delineated a mechanism for GNRH1-induced LHbeta subunit gene (Lhb) transcription, the rate-limiting step in LH production. GNRH1 induces expression of early growth response 1 (EGR1), which interacts with steroidogenic factor 1 (SF1) and paired-like homeodomain transcription factor 1 (PITX1) to regulate Lhb promoter activity. Though the cis-elements for these factors are conserved across species, regulation of human LHB transcription has not been thoroughly investigated. We therefore characterized LHB transcriptional regulation by GNRH1 using promoter-reporter analyses in LbetaT2 cells. GNRH1 stimulated LHB transcription via an extracellular signal-regulated kinase 1/2 pathway. EGR1 bound to two binding sites on the LHB promoter and this binding was increased by GNRH1. Mutation of either site or knockdown of endogenous EGR1 decreased basal and/or GNRH1-regulated promoter activity. The human LHB promoter also contains low and high affinity SF1 binding sites. Mutation of these elements or depletion of endogenous SF1 impaired basal and ligand-induced transcription. Knockdown of PITX1 or PITX2 isoforms impaired GNRH1 induction, and endogenous PITX1 bound to the candidate PITX binding site on the LHB promoter. Thus, the mechanism described for GNRH1 regulation of Lhb in other species is largely conserved for human LHB. We also uncover a previously unappreciated role for PITX2 isoforms in this process.
| S-EPMC2734162 | biostudies-literature
Project description:Identifying the foxglove P450scc through differential transcriptomic analysis.
2023-06-07 | GSE224014 | GEO
Project description:ContextThe LH receptor (LHCGR) drives fetal testosterone secretion, which is vital for human masculinization. Maternal smoking is associated with defective masculinization, but the relationship between smoking, tropic hormones, testosterone, and functional LHCGR expression is poorly understood.ObjectiveThis study aimed to investigate developmental changes in fetal gonadotropins, human chorionic gonadotropin (hCG), and expression of fetal testicular LHCGR isoforms and the effects of maternal cigarette smoking.DesignWe conducted an observational study of the male fetus, comparing pregnancies in which the mothers did or did not smoke.SettingThe study was conducted at the Universities of Aberdeen and Glasgow.Patients/participantsTestes and blood were collected from 54 morphologically normal human male fetuses of women undergoing elective termination of normal second-trimester pregnancies.Main outcome measuresWe measured circulating testosterone, hCG, LH, prolactin, FSH, and testicular LHCGR isoform expression.ResultsFetal testosterone and hCG, but not LH, significantly declined between 11 and 19 wk gestation with no significant change in testicular responsiveness. The proportion of nonfunctional LHCGR transcript in fetal testes was 2.3-fold lower than in adults. Fetal hCG was reduced 38% (P = 0.021) and the ratio of inactive vs. active LHCGR isoforms lowered by smoking.ConclusionsFalling second-trimester fetal testosterone is probably due to declining maternal hCG because Leydig cell LH/hCG responsiveness remains constant. Although maternal cigarette smoking reduces fetal hCG, the ratio of inactive LHCGR isoforms is reduced and gonadotropin drive maintains testosterone production near control levels. The lower relative abundance of inactive isoforms compared with the adult testis reflects the importance of LHCGR.
| S-EPMC2848822 | biostudies-literature
Project description:BACKGROUND: High circulating luteinizing hormone (LH) level is a typical biochemical feature of polycystic ovary syndrome (PCOS) whose pathophysiology is still unclear. Certain mutations of LH and LH receptor (LHR) may lead to changes in bioactivity of these hormones. The aim of this study was determine the role of the LH and LHR polymorphisms in the pathogenesis of PCOS using a genetic approach. METHODS: 315 PCOS women and 212 controls were screened for the gene variants of LH G1052A and LHR rs61996318 polymorphisms by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). RESULTS: PCOS patients had significantly more A allele frequency of LH G1052A mutations than controls (p=0.001). Within PCOS group, carriers of LH 1052A allele had lower LH (p=0.05) and higher fasting glucose levels (p=0.04). No subjects were identified with LHR rs61996318 polymorphisms. A new LHR single nucleotide polymorphism (SNP) was found without clear association with PCOS. CONCLUSIONS: Results suggested LH G1052A mutation might influence PCOS susceptibility and phenotypes.
| S-EPMC3403896 | biostudies-literature
Project description:The effect of luteinizing hormone (luteotropin) and cycloheximide on specific protein synthesis in rat testis Leydig cells has been investigated. Proteins were labelled with either I114C]leucine, [3H]leucine or [35S]methionine during incubation with Leydig-cell suspensions in vitro. Total protein was extracted from the cells and separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. No detectable increase in the synthesis of specific proteins could be observed after incubation of Leydig cells with luteinizing hormone for up to 1 h. However, after a 2h incubation period, an increase in [35S]methionine incorporation was observed in a protein with an apparent mol.wt. of 21000 (referred to as 'protein 21"). When, after labelling of this protein with [35S]-methionine, Leydig cells were incubated for another 30min with cycloheximide, no decrease in radioactivity of this protein band was observed, indicating that it does not have a short half-life. However, another protein band was detected, which after incubation with cycloheximide disappeared rapidly, the reaction following first-order kinetics, with a half-life of about 11 min. This protein, with an apparent mol.wt. of 33000 (referred to as "protein 33"), was found to be located in the particulate fraction of the Leydig cell, and could not be demonstrated in other rat testis-cell types or blood cells. No effect of luteinizing hormone on molecular weight, subcellular localization or half-life of protein 33 was observed. A possible role for protein 33 and protein 21 in the mechanism of action of luteinizing hormone on testosterone production of Leydig cells is discussed.
| S-EPMC1164606 | biostudies-other
Project description:Protein kinase activity was determined in subcellular fractions of rat testis interstitial tissue after incubation of the intact tissue with LH (luteinizing hormone) in vitro. Various factors that might have changed the activity of this enzyme during preparation of the fractions before assay were also investigated. The following results were obtained. 1. LH and 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor) added together during incubation of the interstitial tissue caused a twofold increase in the protein kinase activity in the total tissue homogenate and subcellular fractions (12000g X 5 min pellet and 105000g X 60 min supernatant and pellet). 2. A decrease of approx. 40% in the total amount of protein kinase recovered in the soluble fraction (105000g supernatant) occurred in tissue incubated with LH and 3-isobutyl-1-methylxanthine when compared with the controls. No change in total activity was found in the other fractions. 3. LH and 3-isobutyl-1-methylxanthine caused an increase in cyclic AMP concentration in the soluble fraction (from 30 +/- 6 to 450 +/- 40 pmol/mg of protein, means +/- S.E.M., n = 4), but there was little or no increase in the particulate fractions [from 9 +/- 1 to 13 +/- 3 pmol/mg of protein (n = 3) and from 6 +/- 2 to 23 +/- 11 pmol/mg of protein (n = 3) in the 12000g and 105000g pellets respectively]. 4 Addition of 3-isobutyl-1-methylxanthine alone had little effect on protein kinase activity or cyclic AMP concentrations. 5. Little or no protein kinase activity could be demonstrated in subcellular particulate fractions unless Triton X-100 was added; the effect of this detergent was shown to be at least partly due to the inhibition of adenosine triphosphatase activity. 6. In the presence of Triton X-100 approx. 57% of the total protein kinase activity in the homogenate was found in the 105000g supernatant compared with 11% in the 105000g pellet and 32% in the 12000g pellet. 7. In contrast with adipose-tissue protein kinase [Corbin et al. (1973) J. Biol. Chem. 248, 1813-1821] the relative amounts of cyclic AMP-dependent and -dependent enzyme were not affected by dilution of the interstitial-tissue fractions. NaCl (0.5 M) decreased the estimated total amount of protein kinase activity.
| S-EPMC1172717 | biostudies-other
Project description:Tachykinins (neurokinin A [NKA], neurokinin B [NKB], and substance P [SP]) are important components of the neuroendocrine control of reproduction by direct stimulation of Kiss1 neurons to control GnRH pulsatility, which is essential for reproduction. Despite this role of tachykinins in successful reproduction, knockout (KO) mice for Tac1 (NKA/SP) and Tac2 (NKB) genes are fertile, resembling the phenotype of human patients bearing NKB signaling mutations, who often reverse their hypogonadal phenotype. This suggests the existence of compensatory mechanisms among the different tachykinin ligand-receptor systems to maintain reproduction in the absence of one of them. In order to test this hypothesis, we generated complete tachykinin-deficient mice (Tac1/Tac2KO). Male mice displayed delayed puberty onset and decreased luteinizing hormone (LH) pulsatility (frequency and amplitude of LH pulses) but preserved fertility. However, females did not show signs of puberty onset (first estrus) within 45 days after vaginal opening, they displayed a low frequency (but normal amplitude) of LH pulses, and 80% of them remained infertile. Further evaluation identified a complete absence of the preovulatory LH surge in Tac1/Tac2KO females as well as in wild-type females treated with NKB or SP receptor antagonists. These data confirmed a fundamental role of tachykinins in the timing of puberty onset and LH pulsatility and uncovered a role of tachykinin signaling in facilitation of the preovulatory LH surge. Overall, these findings indicate that tachykinin signaling plays a dominant role in the control of ovulation, with potential implications as a pathogenic mechanism and a therapeutic target to improve reproductive outcomes in women with ovulation impairments.
| S-EPMC7722126 | biostudies-literature
Project description:Histological examination of testes is essential for understanding infertility, sex development, and growth. Therefore, to understand the histomorphology of testes at different developmental stages, we performed hematoxylin and eosin staining of Yak testis. Our results revealed that the diameters of spermatogenic cells and their nuclei were significantly larger (p < 0.05) in the testis at six years compared to at six and 18 months. No significant difference was noted between 30 months and six years. The study was designed to compare the expression profile of LHB in Datong yak. The expression pattern of LHB was explored using quantitative PCR, semi-quantitative PCR, molecular bioinformatic, and Western blot analysis. Our observations indicated that expression of LHB was significantly higher (p < 0.05) in the testis of Datong yak. Western blotting indicated that the molecular mass of LHB protein was 16 kDa in yak. The protein encoded by yak LHB included conserved cysteine-knot domain regions. The high expression of LHB in testis indicated that LHB may be vital for the development of male gonads and the fertility of Datong yak.
| S-EPMC7022877 | biostudies-literature