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Bousfield GR, Harvey DJ. Follicle-Stimulating Hormone Glycobiology. Endocrinology 2019; 160:1515-1535. [PMID: 31127275 PMCID: PMC6534497 DOI: 10.1210/en.2019-00001] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/16/2019] [Indexed: 01/13/2023]
Abstract
FSH glycosylation varies in two functionally important aspects: microheterogeneity, resulting from oligosaccharide structure variation, and macroheterogeneity, arising from partial FSHβ subunit glycosylation. Although advances in mass spectrometry permit extensive characterization of FSH glycan populations, microheterogeneity remains difficult to illustrate, and comparisons between different studies are challenging because no standard format exists for rendering oligosaccharide structures. FSH microheterogeneity is illustrated using a consistent glycan diagram format to illustrate the large array of structures associated with one hormone. This is extended to commercially available recombinant FSH preparations, which exhibit greatly reduced microheterogeneity at three of four glycosylation sites. Macroheterogeneity is demonstrated by electrophoretic mobility shifts due to the absence of FSHβ glycans that can be assessed by Western blotting of immunopurified FSH. Initially, macroheterogeneity was hoped to matter more than microheterogeneity. However, it now appears that both forms of carbohydrate heterogeneity have to be taken into consideration. FSH glycosylation can reduce its apparent affinity for its cognate receptor by delaying initial interaction with the receptor and limiting access to all of the available binding sites. This is followed by impaired cellular signaling responses that may be related to reduced receptor occupancy or biased signaling. To resolve these alternatives, well-characterized FSH glycoform preparations are necessary.
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Affiliation(s)
- George R Bousfield
- Department of Biological Sciences, Wichita State University, Wichita, Kansas
- Correspondence: George R. Bousfield, PhD, Department of Biological Sciences, Wichita State University, 1845 Fairmount Street, Wichita, Kansas 67260. E-mail: ; or David J. Harvey, DSc, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford. Roosevelt Drive, Oxford OX3 7FZ, United Kingdom. E-mail:
| | - David J Harvey
- Target Discovery Institute, Nuffield Department of Medicine, Oxford University, Oxford, United Kingdom
- Correspondence: George R. Bousfield, PhD, Department of Biological Sciences, Wichita State University, 1845 Fairmount Street, Wichita, Kansas 67260. E-mail: ; or David J. Harvey, DSc, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford. Roosevelt Drive, Oxford OX3 7FZ, United Kingdom. E-mail:
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Campo S, Andreone L, Ambao V, Urrutia M, Calandra RS, Rulli SB. Hormonal Regulation of Follicle-Stimulating Hormone Glycosylation in Males. Front Endocrinol (Lausanne) 2019; 10:17. [PMID: 30761084 PMCID: PMC6361742 DOI: 10.3389/fendo.2019.00017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 01/11/2019] [Indexed: 11/13/2022] Open
Abstract
The Follicle-Stimulating Hormone plays an important role in the regulation of gametogenesis. It is synthesized and secreted as a family of glycoforms with differing oligosaccharide structure, biological action, and half-life. The presence of these oligosaccharides is absolutely necessary for the full expression of hormone bioactivity at the level of the target cell. The endocrine milieu modulates the glycosylation of this hormone. During male sexual development a progressive increase in FSH sialylation and in the proportion of glycoforms bearing complex oligosaccharides are the main features in this physiological condition. In late puberty, FSH oligosaccharides are largely processed in the medial- and trans-Golgi cisternae of the gonadotrope and remain without changes throughout adult life. In experimental models, the absence of gonads severely affects FSH sialylation; androgen administration is able to restore the characteristics observed under physiological conditions. The expression of ST6 beta-galactoside alpha-2,6-sialyltransferase 1 is hormonally regulated in the male rat; it decreases after short periods of castration but increases markedly at longer periods of androgen deprivation. Although ST3 beta-galactoside alpha-2,3-sialyltransferase 3 is expressed in the male rat pituitary it is not influenced by changes in the endocrine milieu. The oligosaccharide structure of FSH has an impact on the Sertoli cell endocrine activity. In more advanced stages of Sertoli cell maturation, both sialylation and complexity of the oligosaccharides are involved in the regulation of inhibin B production; moreover, FSH glycoforms bearing incomplete oligosaccharides may enhance the stimulatory effect exerted by gonadal growth factors. In this review, we discuss available information on variation of FSH glycosylation and its hormonal regulation under different physiological and experimental conditions, as well as the effect on Sertoli cell endocrine activity.
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Affiliation(s)
- Stella Campo
- Centro de Investigaciones Endocrinológicas “Dr. César Bergadá” (CEDIE), Buenos Aires, Argentina
- *Correspondence: Stella Campo
| | - Luz Andreone
- Centro de Investigaciones Endocrinológicas “Dr. César Bergadá” (CEDIE), Buenos Aires, Argentina
| | - Verónica Ambao
- Centro de Investigaciones Endocrinológicas “Dr. César Bergadá” (CEDIE), Buenos Aires, Argentina
| | - Mariela Urrutia
- Centro de Investigaciones Endocrinológicas “Dr. César Bergadá” (CEDIE), Buenos Aires, Argentina
| | - Ricardo S. Calandra
- Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
| | - Susana B. Rulli
- Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
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Andreone L, Ambao V, Pellizzari EH, Loreti N, Cigorraga SB, Campo S. Role of FSH glycan structure in the regulation of Sertoli cell inhibin production. Reproduction 2017; 154:711-721. [PMID: 28855248 DOI: 10.1530/rep-17-0393] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/21/2017] [Accepted: 08/30/2017] [Indexed: 01/16/2023]
Abstract
Variations in follicle-stimulating hormone (FSH) carbohydrate composition and structure are associated with important structural and functional changes in Sertoli cells (SCs) during sexual maturation. The aim of the present study was to investigate the impact of FSH oligosaccharide structure and its interaction with gonadal factors on the regulation of monomeric and dimeric inhibin production at different maturation stages of the SC. Recombinant human FSH (rhFSH) glycosylation variants were isolated according to their sialylation degree (AC and BA) and complexity of oligosaccharides (CO and HY). Native rhFSH stimulated inhibin α-subunit (Pro-αC) but did not show any effect on inhibin B (INHB) production in immature SCs isolated from 8-day-old rats. Activin A stimulated INHB and had a synergistic effect on FSH to stimulate Pro-αC. The less acidic/sialylated rhFSH charge analogues, BA, were the only charge analogue mix that stimulated INHB as well as the most potent stimulus for Pro-αC production. Native rhFSH stimulated both Pro-αC and INHB in SCs at a more advanced maturation stage, isolated from 20-day-old rats. In these cells, all rhFSH glycosylation variants increased INHB and Pro-αC production, even in the presence of growth factors. The BA preparation exerted a more marked stimulatory effect on INHB and Pro-αC than the AC. Glycoforms bearing high mannose and hybrid-type oligosaccharides, HY, stimulated INHB and Pro-αC more effectively than those bearing complex oligosaccharides, CO, even in the presence of gonadal growth factors. These findings demonstrate the modulatory effect of FSH oligosaccharide structure on the regulation of inhibin production in the male gonad.
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Affiliation(s)
| | - Verónica Ambao
- Centro de Investigaciones Endocrinológicas 'Dr. Cesar Bergadá' (CEDIE-CONICET) Hospital de Niños 'R. Gutiérrez', Buenos Aires, Argentina
| | - Eliana H Pellizzari
- Centro de Investigaciones Endocrinológicas 'Dr. Cesar Bergadá' (CEDIE-CONICET) Hospital de Niños 'R. Gutiérrez', Buenos Aires, Argentina
| | - Nazareth Loreti
- Centro de Investigaciones Endocrinológicas 'Dr. Cesar Bergadá' (CEDIE-CONICET) Hospital de Niños 'R. Gutiérrez', Buenos Aires, Argentina
| | - Selva B Cigorraga
- Centro de Investigaciones Endocrinológicas 'Dr. Cesar Bergadá' (CEDIE-CONICET) Hospital de Niños 'R. Gutiérrez', Buenos Aires, Argentina
| | - Stella Campo
- Centro de Investigaciones Endocrinológicas 'Dr. Cesar Bergadá' (CEDIE-CONICET) Hospital de Niños 'R. Gutiérrez', Buenos Aires, Argentina
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Arey BJ, López FJ. Are circulating gonadotropin isoforms naturally occurring biased agonists? Basic and therapeutic implications. Rev Endocr Metab Disord 2011; 12:275-88. [PMID: 21706143 DOI: 10.1007/s11154-011-9188-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The gonadotropins, luteinizing hormone, human chorionic gonadotropin and follicle-stimulating hormone, are key regulators of reproduction. As a result of this function, they have been the focus of research for many years. Isolated or recombinant proteins have been successfully used therapeutically for the treatment of infertility; and, in the case of compounds that block gonadotropin activity, for their potential utility in contraception. Until recently, selective small molecules modulating gonadotropin receptor activity have proven difficult to identify. The gonadotropins are glycoproteins that are released into the plasma as differently glycosylated isoforms and bind to specific G protein-coupled receptors. The degree of glycosylation on the gonadotropins has been shown to be important for the biological activities of these hormones and is differentially regulated depending on the steroidal status. Recent data from the study of glycosylated variants of LH, hCG and FSH have revealed that these isoforms have distinct signaling properties that allow for gonadotropin pleiotropic signals to be transduced effectively at the level of the receptor. Thus, glycosylated variants of the gonadotropins behave as biased agonists. Recently, newly developed, small molecule, synthetic allosteric compounds have been identified that are capable of mimicking this biased signaling. This opens the door to development of orally available, drug-like therapies for reproductive disorders that offer similar pleiotropic richness as that offered by the complex, endogenous hormones.
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Affiliation(s)
- Brian J Arey
- Metabolic and Cardiovascular Drug Discovery, Research and Development, Bristol-Myers Squibb Co., 311 Pennington-Rocky Hill Rd., Mail Stop- 21-1.08, Hopewell, NJ 08543, USA.
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Campo S, Ambao V, Creus S, Gottlieb S, Fernandez Vera G, Benencia H, Bergadá C. Carbohydrate complexity and proportions of serum FSH isoforms in the male: lectin-based studies. Mol Cell Endocrinol 2007; 260-262:197-204. [PMID: 17084021 DOI: 10.1016/j.mce.2006.01.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Accepted: 01/03/2006] [Indexed: 11/25/2022]
Abstract
FSH is synthesized and secreted in multiple molecular forms with different oligosaccharide structures which are needed for full expression of biological activity. GnRH and sex steroids modulate oligosaccharide structure and composition. In the present study we have assessed the carbohydrate complexity and proportion of circulating FSH isoforms during puberty, aging and after androgen administration to pubertal anorchid boys. Preparative isoelectrofocusing and lectin chromatography were used to isolate FSH isoforms on the basis of charge and internal carbohydrate complexity. Differences in sialic acid content and a progressive increase of isoforms bearing highly branched oligosaccharides were found during puberty. Less acidic, more bioactive FSH isoforms, secreted at mid-puberty may modulate important maturational events in the Sertoli cell population. Androgen administration to pubertal anorchid boys favoured the secretion of this type of isoforms. In adult men, the predominance of FSH isoforms bearing complex type oligosaccharides remained unchanged until very advanced age. These results show that the predominance of FSH isoforms bearing fully processed oligosaccharides in circulation may contribute to the development and maintenance of seminiferous epithelium function in men.
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Affiliation(s)
- S Campo
- Centro de Investigaciones Endocrinológicas, Hospital General de Niños "R. Gutiérrez", Gallo 1330, C1425EFD Buenos Aires, Argentina.
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Chávez-Genaro R, Lombide P, Domínguez R, Rosas P, Vázquez-Cuevas F. Sympathetic pharmacological denervation in ageing rats: effects on ovulatory response and follicular population. Reprod Fertil Dev 2007; 19:954-60. [DOI: 10.1071/rd07075] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 09/16/2007] [Indexed: 11/23/2022] Open
Abstract
The present study analyses the participation of ovarian innervation during reproductive senescence. We use the model of acute peripheral pharmacological sympathetic denervation with guanethidine in young (3 months old), middle-aged (12 months old) or old (18 months old) rats with spontaneous or induced ovulation. Ovarian levels of norepinephrine (NE) were measured by HPLC and the oestrous cycle, the number of ovulating animals and the percentage of atretic follicles were also assessed. Aged animals showed a progressive reduction in ovulatory capacity and an increase in ovarian NE content. Acute denervation increased the percentage of healthy follicles in 12- and 18-month-old rats compared with control adult animals. Combined treatment of denervation plus stimulation with gonadotrophins doubled the number of ova shed in young adult rats and restablished a partial ovulation in 12-month-old rats. The results suggest that ovarian noradrenergic innervation plays a modulator role in ovarian physiology during the ageing ovary process. The action of ovarian noradrenergic innervation seems to be associated with folliculogenesis and the ovarian response to gonadotrophins.
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Lin YWP, Petrino TR, Wallace RA. Fundulus heteroclitus gonadotropins.5: Small scale chromatographic fractionation of pituitary extracts into components with different steroidogenic activities using homologous bioassays. Reprod Biol Endocrinol 2004; 2:14. [PMID: 15040801 PMCID: PMC407852 DOI: 10.1186/1477-7827-2-14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2004] [Accepted: 03/24/2004] [Indexed: 11/22/2022] Open
Abstract
Fractionation and characterization of gonadotropins (GtH) from Fundulus heteroclitus pituitary extracts were carried out using a biocompatible liquid chromatographic procedure (Pharmacia FPLC system). Chromatographic fractions were monitored for gonadotropic activities (induction of oocyte maturation and steroid production) using homologous follicle bioassays in vitro. Size-exclusion chromatography eluted gonadotropic activity in one major protein peak (Mr approximately 30,000). Anion-exchange and hydrophobic-interaction chromatography (HIC) yielded two distinct peaks of 17beta-estradiol (E2)- and 17alpha-hydroxy,20beta-dihydroprogesterone (DHP)-promoting activity with associated oocyte maturation. Two-dimensional chromatography (chromatofocusing followed by HIC) resolved pituitary extracts into two active fractions; both induced E2 synthesis, but one was relatively poor in eliciting DHP and testosterone production. Thus, using homologous bioassays, at least two quantitatively different gonadotropic (steroidogenic) activities: an E2-promoting gonadotropin (GtH I-like) and a DHP-promoting gonadotropin (GtH II-like), which has a lower isoelectric point but greater hydrophobicity than the former, can be distinguished from F. heteroclitus pituitaries by a variety of chromatographic procedures. This study complements previous biochemical and molecular data in F. heteroclitus and substantiates the duality of GtH function in a multiple-spawning teleost.
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Affiliation(s)
- Yu-Wai Peter Lin
- Barry University, School of Natural & Health Sciences, Miami Shores, Florida 33161, USA
| | - Teresa R Petrino
- Barry University, School of Natural & Health Sciences, Miami Shores, Florida 33161, USA
| | - Robin A Wallace
- Whitney Laboratory, University of Florida, St. Augustine, Florida 32086, USA
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Zambrano E, Zariñán T, Olivares A, Barrios-de-Tomasi J, Ulloa-Aguirre A. Receptor binding activity and in vitro biological activity of the human FSH charge isoforms as disclosed by heterologous and homologous assay systems: implications for the structure-function relationship of the FSH variants. Endocrine 1999; 10:113-21. [PMID: 10451219 DOI: 10.1385/endo:10:2:113] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/1998] [Revised: 01/20/1999] [Accepted: 01/20/1999] [Indexed: 11/11/2022]
Abstract
Follicle-stimulating hormone (FSH) is produced and secreted in multiple molecular forms. These isoforms differ in their oligosaccharide structures, which determine the particular behavior of a given variant in in vitro and in vivo systems. Employing heterologous cell assay systems, this and other laboratories have shown that highly sialylated human FSH variants exhibit lower receptor binding/immunoactivity as well as in vitro bioactivity/immunoactivity relationships than their less sialylated counterparts. It is not known, however, whether this characteristic behavior of the FSH isoforms is reproduced by homologous assay systems, in which unique variants of the receptor are presumptively expressed. To gain further insights into the structure-activity relationship of the various FSH isoforms, we analyzed the capacity of nine charge isoforms obtained after high-resolution chromatofocusing (pH window, 7.10 to <3.80) of anterior pituitary glycoprotein extracts to bind and activate their cognate receptor expressed by naturally occurring heterologous cell systems (rat granulosa cells and seminiferous tubule homogenates) as well as by human embryonic kidney-derived 293 (HEK-293) cells transfected with the human FSH (FSH-R) receptor cDNA. In both (heterologous and homologous) receptor assay systems, the isoforms displaced 125I-labeled FSH from the receptor in a dose-response manner; however, whereas in the heterologous systems, the receptor binding activity varied according to the elution pH value/sialic content of the isoforms, with the less acidic variants exhibiting higher receptor binding activity (r = 0.851 and 0.495 [p < 0.01 and p < 0.05] for the granulosa cell and testicular homogenate receptor assay systems, respectively) than the more acidic/sialylated analogs, in the homologous assay, this relationship was practically absent (r = 0.372, p N.S.). The capacity of the isoforms to induce androgen aromatization by rat granulosa cells followed the same trend shown by its corresponding receptor assay system (r = 0.864, p < 0.01). Interestingly and in contrast to the results observed in the homologous receptor binding assay, the ability of the isoforms to induce cAMP production by HEK-293 cells varied according to their elution pH value, with the more sialylated isoforms exhibiting lower potency than their less acidic counterparts (r = 0.852, p < 0.01). The results yielded by the heterologous assays suggest that the different potency of the isoforms to elicit a biological effect in a naturally occurring receptor system depends primarily on the particular affinity of the receptor molecule for each isoform. The existence of a clear dissociation between receptor binding and signal transduction in the homologous system indicate that this later function is rather related to the different ability of the FSH glycosylation variants to induce and/or stabilize distinct receptor conformations that may permit preferential or different degrees of activation/inhibition of a given signal transduction pathway. Thus, the human FSH receptor-transducer system apparently possesses sufficient versatility to respond in a different manner to glycosylation-dependent diverse FSH signals.
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Affiliation(s)
- E Zambrano
- Department of Reproductive Biology, Instituto Nacional de la Nutrición Salvador Zubirán, México DF, Mexico
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Cooke D, Crowe M, Roche J, Headon D. Gonadotrophin heterogeneity and its role in farm animal reproduction. Anim Reprod Sci 1996. [DOI: 10.1016/0378-4320(95)01449-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Costagliola S, Niccoli P, Carayon P. Glycoprotein hormone isomorphism and assay discrepancy: the paradigm of luteinizing hormone (LH). J Endocrinol Invest 1994; 17:291-9. [PMID: 7523478 DOI: 10.1007/bf03348981] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- S Costagliola
- Laboratoire de Biochimie Endocrinienne, Faculté de Médecine, Marseille, France
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Harsch IA, Simoni M, Nieschlag E. Molecular heterogeneity of serum follicle-stimulating hormone in hypogonadal patients before and during androgen replacement therapy and in normal men. Clin Endocrinol (Oxf) 1993; 39:173-80. [PMID: 8370130 DOI: 10.1111/j.1365-2265.1993.tb01770.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE The present study was performed to characterize the molecular heterogeneity of serum FSH in normal males and to investigate the possible influence of testosterone on serum FSH in androgen-deficient men before and during testosterone administration. DESIGN AND PATIENTS Serum samples were taken at 10-minute intervals between 0730 and 0830 h from nine healthy, eugonadal men and from eight men with primary hypogonadism (Klinefelter's syndrome). In the hypogonadal patients, sampling was performed before treatment (n = 8), 4-5 days after the first and the third injection of 250 mg testosterone enanthate given intramuscularly at three-weekly intervals (n = 6), as well as 3 months after the onset of therapy (n = 3). Sampling was repeated 7 days apart in two of the nine healthy volunteers. MEASUREMENTS Aliquots from the individual serum samples were pooled and fractionated by chromatofocusing in the pH range 6-3. Immunoreactive FSH was measured by immunofluorometric assay (IFMA) in each fraction and the individual serum samples. In each serum pool, bioactive FSH was determined by in-vitro bioassay (rat Sertoli cell aromatase bioassay), testosterone by RIA and LH by IFMA. RESULTS After grouping the percentage of immunoreactive FSH recovered in the individual fractions into intervals of 0.5 pH units, significant differences between controls and patients were observed in the pH regions 4-4.5, 5.5-6 and 6-6.5. No statistically significant changes in the isoform distribution of FSH were detected during therapy in the Klinefelter patients. A high degree of variability, which did not follow a common pattern, was observed in the isoform distribution of FSH within the same individuals, both in the hypogonadal patients during treatment and in the two normal men whose blood samples were taken on two different occasions. CONCLUSIONS Serum FSH is highly heterogeneous in normal and hypogonadal men. There is a spontaneous intra-individual variability in the relative abundance of the different FSH isoforms in serum that may most probably be related to metabolic deglycosylation of FSH. Minor but significant differences in the molecular heterogeneity of serum FSH could be demonstrated in Klinefelter patients compared to normal men. These differences are not modified by administration of testosterone enanthate at doses achieving normal androgenization, suggesting that factors different from testosterone may modulate FSH pleomorphism.
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Affiliation(s)
- I A Harsch
- Institute of Reproductive Medicine, University and WHO Collaborating Centre for Research in Human Reproduction, Münster, Germany
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Hsueh AJ, Bicsak TA, Jia XC, Dahl KD, Fauser BC, Galway AB, Czekala N, Pavlou SN, Papkoff H, Keene J. Granulosa cells as hormone targets: the role of biologically active follicle-stimulating hormone in reproduction. RECENT PROGRESS IN HORMONE RESEARCH 1989; 45:209-73; discussion 273-7. [PMID: 2510224 DOI: 10.1016/b978-0-12-571145-6.50009-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Baenziger JU, Green ED. Pituitary glycoprotein hormone oligosaccharides: structure, synthesis and function of the asparagine-linked oligosaccharides on lutropin, follitropin and thyrotropin. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 947:287-306. [PMID: 3130893 DOI: 10.1016/0304-4157(88)90012-3] [Citation(s) in RCA: 211] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Luteinizing hormone (LH), follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) from pituitary and chorionic gonadotropin (CG) from placenta are a family of closely related glycoproteins. Each hormone is a heterodimer, consisting of an alpha- and a beta-subunit. Within an animal species, the alpha-subunits of all four glyco-protein hormones have an identical amino acid sequence, whereas each beta-subunit is distinct and confers hormone-specific features to the heterodimer. LH and FSH are synthesized within the same cell, the gonadotroph of the anterior pituitary, but are predominantly stored in separate secretory granules. We have characterized the asparagine-linked oligosaccharides on bovine, ovine and human LH, FSH and TSH. The various pituitary hormones were found to contain unique sulfated oligosaccharides with the terminal sequence SO4-4GalNAc beta 1----4GlcNAc beta 1----2Man alpha, sialylated oligosaccharides with the terminal sequence SA alpha Gal beta GlcNAc beta Man alpha, or both sulfated and sialylated structures. Despite synthesis of LH and FSH in the same pituitary cell, sulfated oligosaccharides predominate on LH while sialylated oligosaccharides predominate on FSH for all three animal species. We have examined the reactions leading to synthesis of the sulfated oligosaccharides to determine which steps are hormone specific. The sulfotransferase is oligosaccharide specific, requiring only the sequence GalNAc beta 1----4GlcNAc beta 1----2Man alpha. In contrast, the GalNAc-transferase appears to be protein specific, accounting for the preferential addition of GalNAc to LH, TSH, and free (uncombined) alpha-subunits compared with FSH and other pituitary glycoproteins. The predominance of sulfated oligosaccharide structures on LH may account for sorting of LH and FSH into separate secretory granules. Differences in sulfation and sialylation of LH, FSH and TSH may also play a role in the regulation of hormone bioactivity.
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Affiliation(s)
- J U Baenziger
- Department of Pathology, Washington University Medical School, St. Louis, MO 63110
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Ando H, Ishii S. Separation of gonadotropic fractions with different species specificities from tuna pituitaries. Gen Comp Endocrinol 1988; 70:181-92. [PMID: 2838377 DOI: 10.1016/0016-6480(88)90139-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Eight different gonadotropic glycoprotein fractions were separated from the acetone-dried powder of yellow fin tuna pituitary glands by successive chromatographies on Superose 12 for gel filtration and Mono Q for anion exchange using the Pharmacia fast protein liquid chromatography system. This was preceded by preliminary separations using an ammonium sulfate precipitation method and affinity chromatography on concanavalin A-Sepharose. For biological characterization, we employed two radioreceptor assay systems, one using goby testis plasma membranes and silver carp GTH as the receptor and radioligand, respectively, and the other using testis plasma membranes of the yellow fin tuna and gonadotropin of the same species, respectively. We also employed two testicular cyclic AMP accumulation bioassay methods in vitro, one with the goby testis and the other with the mackerel testis. The least acidic fraction after Mono Q was further separated into four subfractions by rechromatography with Mono Q. They were strongly active in the tuna and mackerel assays but almost inactive in the goby assays. They were referred to as tuna-type tuna gonadotropin. In contrast, the most acidic fraction obtained after the first Mono Q was active in the goby assays but almost inactive in the tuna and mackerel assays. It was referred to as goby-type tuna gonadotropin. The intermediate fractions were active on both assays and are considered to be mixtures of tuna-type and goby-type gonadotropins. The reason for the presence of gonadotropin inactive to homologous species is discussed from the evolutionary viewpoint.
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Affiliation(s)
- H Ando
- Department of Biology, School of Education, Waseda University, Tokyo, Japan
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Chapter 9 Mechanism of action of FSH in the ovary. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/s0167-7306(08)60664-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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