Isolation and characterization of three forms of luteinizing hormone from the pituitary gland of the horse.
Abstract: Three isoforms of equine luteinizing hormone (eLH-A, eLH-B and eLH-C) have been isolated from horse pituitary glands. Separation was achieved on the basis of charge heterogeneity by ion-exchange chromatography. These charge differences were apparent after final purification, as determined by electrophoretic mobility on polyacrylamide disc gels (RF = 0.14, 0.19 and 0.26 for eLH-A, -B and -C, respectively). Apparent size differences were also noted between the isohormones by gel filtration on Sephadex G-100. Ve/Vo ratios for eLH-A, -B and -C were 1.72, 1.54 and 1.47, respectively. All 3 isoforms were found to contain an equivalent amount of hexose (9.0-9.2%). Isohormones eLH-B and eLH-C, however, possess more sialic acid than eLH-A (6.6-6.7%, vs. 4.5%). The eLH-A and eLH-B preparations contain a similar amount of hexosamine, which is slightly lower than the amount of eLH-C (8.8-9.1% vs. 11.2%). No differences were noted between the isohormones by rat Leydig cell LH bioassay, equine testis LH radioreceptor assay (RRA) or calf testis follicle-stimulating hormone (FSH) RRA. Slight, but nonsignificant, variations were noted between preparations in an eLH radioimmunoassay (RIA). Although chemical variations were detected between the eLH isoforms, no significant differences were observed in in vitro biological and immunological activities. The differences detected in sialic acid content raises the possibility that differences in in vivo clearance rates may exist.
Publication Date: 1986-04-01 PubMed ID: 3008870DOI: 10.1095/biolreprod34.3.571Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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The research is about the isolation and characterization of three forms of horse luteinizing hormone from the pituitary glands of horses. There are no distinct differences in their biological and immunological functionalities, despite noticeable chemical variations.
Isolation and Characterization Process
- The scientists were able to isolate three isoforms of equine luteinizing hormone from horse pituitary glands. These were labeled as eLH-A, eLH-B, and eLH-C.
- The separation of these isoforms was achieved using ion-exchange chromatography based on the charge heterogeneity.
- After their purification, the different charges between these hormones were quite clear as demonstrated by their electrophoretic mobility on polyacrylamide disc gels. The RF values for eLH-A, -B, and -C were 0.14, 0.19, and 0.26, respectively.
- Apparent size differences were also observed between the isoforms when examined through gel filtration on Sephadex G-100. This was measured using Ve/Vo ratios with 1.72, 1.54, and 1.47 for eLH-A, -B, and -C, respectively.
Chemical Composition
- All three isoforms were found to contain comparable amounts of hexose (sugar), around 9.0-9.2%.
- However, there were differences in their sialic acid content, with eLH-B and eLH-C possessing more than eLH-A (6.6-6.7% vs. 4.5%).
- Similar amounts of hexosamine, another sugar, were noted in eLH-A and eLH-B, with a slightly lower amount found in eLH-C (8.8-9.1% vs. 11.2%).
Biological and Immunological Functionality
- No differences were observed between the hormones when evaluated using rat Leydig cell LH bioassay, the equine testis LH radioreceptor assay (RRA), or the calf testis follicle-stimulating hormone (FSH) RRA.
- Very minor, but not significant, variations were noted between preparations in an eLH radioimmunoassay (RIA).
- Despite the noted chemical variations, the in vitro biological and immunological functionalities of the isoforms were found to be not significantly different.
- Differences detected in sialic acid content suggest there may be differences in their in vivo clearance rates.
Cite This Article
APA
Matteri RL, Papkoff H, Ng DA, Swedlow JR, Chang YS.
(1986).
Isolation and characterization of three forms of luteinizing hormone from the pituitary gland of the horse.
Biol Reprod, 34(3), 571-578.
https://doi.org/10.1095/biolreprod34.3.571 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Biological Assay
- Carbohydrates / analysis
- Chromatography, DEAE-Cellulose
- Electrophoresis, Polyacrylamide Gel
- Horses / physiology
- Luteinizing Hormone / immunology
- Luteinizing Hormone / isolation & purification
- Luteinizing Hormone / metabolism
- Receptors, Cell Surface / metabolism
- Receptors, FSH
- Receptors, LH
- Structure-Activity Relationship
Grant Funding
- HD-05722 / NICHD NIH HHS
Citations
This article has been cited 1 times.- Lin YW, 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 Mar 24;2:14.
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