Editing Luteinizing hormone (section)

== Structure ==

LH is a [[heterodimeric]] [[glycoprotein]]. Each [[monomeric]] unit is a [[glycoprotein]] molecule; one alpha and one beta subunit make the full, functional protein.

Its structure is similar to that of the other [[glycoprotein hormones]], [[follicle-stimulating hormone]] (FSH), [[thyroid-stimulating hormone]] (TSH), and [[human chorionic gonadotropin]] (hCG). The protein dimer contains 2 glycopeptidic subunits (labeled alpha- and beta- subunits) that are non-covalently associated:<ref name="pmid24001578">{{cite journal | vauthors = Jiang X, Dias JA, He X | title = Structural biology of glycoprotein hormones and their receptors: insights to signaling | journal = Molecular and Cellular Endocrinology | volume = 382 | issue = 1 | pages = 424–451 | date = January 2014 | pmid = 24001578 | doi = 10.1016/j.mce.2013.08.021 | doi-access = free }}</ref>
* The ''[[Alpha subunit of glycoprotein hormones|alpha subunits]]'' of LH, FSH, TSH, and hCG are identical, and contain 92 [[amino acids]] in human but 96 [[amino acids]] in almost all other vertebrate species (glycoprotein hormones do not exist in invertebrates).
* The ''beta subunits'' vary. LH has a beta subunit of  120 amino acids (LHB) that confers its specific biologic action and is responsible for the specificity of the interaction with the [[LH receptor]]. This beta subunit contains an amino acid sequence that exhibits large homologies with that of the beta subunit of [[Human chorionic gonadotropin|hCG]] and both stimulate the same receptor.  However, the hCG beta subunit contains an additional 24 amino acids, and the two hormones differ in the composition of their sugar moieties.

The different composition of these [[oligosaccharide]]s affects bioactivity and speed of degradation. The biologic [[half-life]] of LH is 20 minutes, shorter than that of  FSH (3–4 hours) and hCG (24 hours).{{Citation needed|date=November 2008}} The biological [[half-life]] of LH is 23 hours subcutaneous<ref>{{cite journal | vauthors = Ezcurra D, Humaidan P | title = A review of luteinising hormone and human chorionic gonadotropin when used in assisted reproductive technology | journal = Reproductive Biology and Endocrinology | volume = 12 | issue = 1 | pages = 95 | date = October 2014 | pmid = 25280580 | pmc = 4287577 | doi = 10.1186/1477-7827-12-95 | doi-access = free }}</ref> or terminal half life of 10-12 hours.<ref>{{cite journal | vauthors = le Cotonnec JY, Porchet HC, Beltrami V, Munafo A | title = Clinical pharmacology of recombinant human luteinizing hormone: Part I. Pharmacokinetics after intravenous administration to healthy female volunteers and comparison with urinary human luteinizing hormone | journal = Fertility and Sterility | volume = 69 | issue = 2 | pages = 189–194 | date = February 1998 | pmid = 9496327 | doi = 10.1016/S0015-0282(97)00501-3 | doi-access =  }}</ref>