Growth hormone 2 (GH2), also known more commonly as placental growth hormone (PGH) or growth hormone variant (GH-V), is a protein that in humans is encoded by the GH2 gene. [3] [4] It is produced by and secreted from the placenta during pregnancy, and becomes the predominant form of growth hormone (GH) in the body during this time. [5] [6] Its cogener is growth hormone 1 (GH1), or pituitary growth hormone.
The protein encoded by this gene is a member of the somatotropin/prolactin family of hormones, playing an important role in growth control. The gene, along with four other related genes, is located at the growth hormone locus on chromosome 17, where they are interspersed in the same transcriptional orientation; an arrangement that is thought to have evolved through a series of gene duplications. The five genes share a remarkably high degree of sequence identity. Alternative splicing generates additional isoforms of each of the five growth hormones, leading to further diversity and the potential for specialization. As in the case of its pituitary counterpart, growth hormone 1, the predominant isoform of this particular family member shows similar somatogenic activity with reduced lactogenic activity. Mutations in this gene lead to placental growth hormone/lactogen deficiency. [4]
Thyroxine-binding globulin (TBG) is a globulin protein that in humans is encoded by the SERPINA7 gene. TBG binds thyroid hormones in circulation. It is one of three transport proteins (along with transthyretin and serum albumin) responsible for carrying the thyroid hormones thyroxine (T4) and triiodothyronine (T3) in the bloodstream. Of these three proteins, TBG has the highest affinity for T4 and T3 but is present in the lowest concentration relative to transthyretin and albumin, which also bind T3 and T4 in circulation. Despite its low concentration, TBG carries the majority of T4 in the blood plasma. Due to the very low concentration of T4 and T3 in the blood, TBG is rarely more than 25% saturated with its ligand. Unlike transthyretin and albumin, TBG has a single binding site for T4/T3. TBG is synthesized primarily in the liver as a 54-kDa protein. In terms of genomics, TBG is a serpin; however, it has no inhibitory function like many other members of this class of proteins.
Corticosteroid 11-β-dehydrogenase isozyme 2 also known as 11-β-hydroxysteroid dehydrogenase 2 is an enzyme that in humans is encoded by the HSD11B2 gene.
Leucyl/cystinyl aminopeptidase, also known as cystinyl aminopeptidase (CAP), insulin-regulated aminopeptidase (IRAP), human placental leucine aminopeptidase (PLAP), oxytocinase, and vasopressinase, is an enzyme of the aminopeptidase group that in humans is encoded by the LNPEP gene.
POU domain, class 1, transcription factor 1 , also known as POU1F1, is a transcription factor for growth hormone.
Homeobox expressed in ES cells 1, also known as homeobox protein ANF, is a homeobox protein that in humans is encoded by the HESX1 gene.
Gonadotropin-releasing hormone receptor is a protein that in humans is encoded by the GNRHR gene.
Insulin-like growth factor-binding protein 2 is a protein that in humans is encoded by the IGFBP2 gene.
Inhibin, alpha, also known as INHA, is a protein which in humans is encoded by the INHA gene.
Follitropin subunit beta also known as follicle-stimulating hormone beta subunit (FSH-B) is a protein that in humans is encoded by the FSHB gene. Alternative splicing results in two transcript variants encoding the same protein.
Hydroxyprostaglandin dehydrogenase 15-(NAD), also called 15-hydroxyprostaglandin dehydrogenase [NAD+], is an enzyme that in humans is encoded by the HPGD gene.
Homeobox protein prophet of PIT-1 is a protein that in humans is encoded by the PROP1 gene.
Progonadoliberin-2 is a protein that in humans is encoded by the GNRH2 gene.
Corticotropin-releasing factor-binding protein is a protein that in humans is encoded by the CRHBP gene. It belongs to corticotropin-releasing hormone binding protein family.
Choriogonadotropin subunit beta variant 1 is a protein that in humans is encoded by the CGB1 gene.
Early placenta insulin-like peptide is a protein that in humans is encoded by the INSL4 gene.
Choriogonadotropin subunit beta variant 2 is a protein that in humans is encoded by the CGB2 gene.
UDP-glucuronosyltransferase 2B17 is an enzyme that in humans is encoded by the UGT2B17 gene.
Luteinizing hormone subunit beta also known as lutropin subunit beta or LHβ is a polypeptide that in association with an alpha subunit common to all gonadotropin hormones forms the reproductive signaling molecule luteinizing hormone. In humans it is encoded by the LHB gene.
Thyroid stimulating hormone, beta also known as TSHB is a protein which in humans is encoded by the TSHB gene.
The Somatotropin family is a protein family whose titular representative is somatotropin, also known as growth hormone, a hormone that plays an important role in growth control. Other members include choriomammotropin (lactogen), its placental analogue; prolactin, which promotes lactation in the mammary gland, and placental prolactin-related proteins; proliferin and proliferin related protein; and somatolactin from various fishes. The 3D structure of bovine somatotropin has been predicted using a combination of heuristics and energy minimisation.