Journal ArticleDOI
The prolactin/growth hormone receptor family.
TLDR
It is doubtful that one unifying mechanism of action will be found for this hormone, as several potential components of the signal transduction pathways have been identified, but as yet none has clearly been shown to be able to mimic the effect of PRL or GH.Abstract:
PRL and GH are hormones with a wide spectrum of actions. Specific receptors are widely distributed in a number of classical target organs, but other tissues that are not known targets also contain measurable binding sites or receptor mRNA. The most likely explanation is that PRL and GH cause effects that have not yet been characterized in certain tissues. Cloning of the cDNAs encoding PRL and GH receptors has led to the discovery that the receptors, like the hormones themselves, form a gene family. Multiple receptor forms have been identified, including a short form, which for PRL is a membrane-bound receptor or for GH is a soluble BP, and a long form, which for both PRL and GH is a membrane-bound receptor. PRL and GH receptors, and the mRNAs encoding them, can be up- and down-regulated. GH induces an up-regulation of both GH and PRL receptors, whereas PRL stimulates an increase of only its own receptor. High concentrations of either hormone induce a homologous down-regulation of receptor expression. An assay has been developed to measure the functional activity of different forms of PRL receptor by cotransfecting a milk protein fusion gene specific to PRL coupled to a reporter-gene along with the cDNA of the PRL receptor. Although the short form represents the major form present in rat mammary gland, only the long form of receptor is able to stimulate milk protein gene transcription. For GH, increased expression of the receptor in some target cells is accompanied by a modest enhancement of the response to GH. No single second messenger mediating the action of either PRL or GH has been identified. Several potential components of the signal transduction pathways have been identified, but as yet none has clearly been shown to be able to mimic the effect of PRL or GH. Because of the wide range of biological actions associated with PRL, and the existence of various forms of PRL receptors, it is doubtful that one unifying mechanism of action will be found for this hormone. No human or animal model of a genetic defect of the PRL receptor has thus far been published. Mutations in the GH receptor gene have been demonstrated in Laron type dwarfism. Different exon deletions or point or nonsense mutations resulting in modifications in the extracellular, GH binding region of the GH receptor have been reported.(ABSTRACT TRUNCATED AT 400 WORDS)read more
Citations
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Journal ArticleDOI
Prolactin: Structure, Function, and Regulation of Secretion
TL;DR: The purpose of this review is to provide a comprehensive survey of the current understanding of prolactin's function and its regulation and to expose some of the controversies still existing.
Journal ArticleDOI
Prolactin (PRL) and Its Receptor: Actions, Signal Transduction Pathways and Phenotypes Observed in PRL Receptor Knockout Mice
TL;DR: It is clear that there are multiple actions associated with PRL, and the technique of gene targeting in mice has been used to develop the first experimental model in which the effect of the complete absence of any lactogen or PRL-mediated effects can be studied.
Journal ArticleDOI
Nutritional Regulation of the Insulin-Like Growth Factors*
TL;DR: The exquisite sensitivity of circulating IGF-I to nutrients, the nycthemeral stability of its concentrations and its relative short half-life constitute the basis for its use as a marker of both nutritional status and adequacy of nutritional rehabilitation.
Journal ArticleDOI
Genetic conflicts in human pregnancy.
TL;DR: The placenta is able to release hormones and other substances directly into the maternal circulation as discussed by the authors, which can be interpreted as an attempt by a poorly nourished fetus to increase its supply of nutrients by increasing the resistance of its mother's peripheral circulation.
Journal ArticleDOI
Mammary gland factor (MGF) is a novel member of the cytokine regulated transcription factor gene family and confers the prolactin response
TL;DR: The mammary gland factor, MGF, has been shown to be a central mediator in the lactogenic hormone response and the DNA binding activity of MGF is hormonally regulated and essential for beta‐casein promoter activity.
References
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Structural design and molecular evolution of a cytokine receptor superfamily.
TL;DR: This work proposes that the approximately 200-residue binding segment of the canonical cytokine receptor is composed of two discrete folding domains that share a significant sequence and structural resemblance with a likely binding site for cytokine ligands.
Journal ArticleDOI
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David W. Leung,Steven A. Spencer,George Cachianes,R. Glenn Hammonds,Carol Collins,William J. Henzel,Ross Barnard,Michael J. Waters,William I. Wood +8 more
TL;DR: The complete amino-acid sequences derived from complementary DNA clones encoding the putative human and rabbit growth hormone receptors are not similar to other known proteins, demonstrating a new class of transmembrane receptors.
Journal ArticleDOI
Interleukin-6 triggers the association of its receptor with a possible signal transducer, gp130
Tetsuya Taga,Masahiko Hibi,Y. Hirata,Katsuhiko Yamasaki,Kiyoshi Yasukawa,Tadashi Matsuda,Toshio Hirano,Tadamitsu Kishimoto +7 more
TL;DR: It is reported that an 80 kd single polypeptide chain (IL-6-R) is involved in IL-6 binding and that IL- 6 triggers the association of this receptor with a non-ligand-binding membrane glycoprotein, gp130, extracellularly and can provide the IL-7 signal.
Journal ArticleDOI
Molecular cloning and expression of an IL-6 signal transducer, gp130
Masahiko Hibi,Masaaki Murakami,Mikiyoshi Saito,Toshio Hirano,Tetsuya Taga,Tadamitsu Kishimoto +5 more
TL;DR: A cloned gp130 could associate with a complex of IL-6 and solubleIL-6-R and transduce the growth signal when expressed in a murine IL-3-dependent cell line and confirmed that a gp130 is involved in the formation of high affinity IL- 6 binding sites.
Journal ArticleDOI
Cloning and expression of the human interleukin-6 (BSF-2/IFN beta 2) receptor
Katsuhiko Yamasaki,Tetsuya Taga,Y. Hirata,Hideo Yawata,Yoshikazu Kawanishi,Brian Seed,Tadatsugu Taniguchi,Toshio Hirano,Tadamitsu Kishimoto +8 more
TL;DR: A complementary DNA encoding the human IL-6 receptor (IL-6-R) has now been isolated and consists of 468 amino acids, including a signal peptide of approximately 19 amino acids and a domain of approximately 90 amino acids that is similar to a domain in the immunoglobulin (Ig) superfamily.