Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rabbit placentas were extracted with 0.7 N HCl-acetone (3:5, vol/vol) containing protease inhibitors. Gel filtration (Sephadex G-50) followed by ion exchange chromatography (carboxymethyl cellulose) separated a bioactive relaxin-like fraction with a specific activity of 8.5 U/mg protein as determined by the in vitro mouse uterus bioassay. Column chromatography using Sepharose CL-4B in 6 M guanidine HCl was employed to purify the bioactive sample. The yield of the purified relaxin-like protein was 12 micrograms/g placenta and the specific activity was 23 U/mg protein. The bioactive sample was also immunoreactive after being electrophoretically transferred to nitrocellulose paper and stained using rabbit antiporcine relaxin serum and peroxidase-antiperoxidase immunochemistry. Isoelectrofocusing of the purified relaxin-like protein revealed one band with an isoelectric point of approximately 6.5. The apparent molecular weight of the rabbit relaxin was approximately 7200 as determined by sodium dodecyl sulfate-urea slab gel electrophoresis. Upon reduction with 5.0% mercaptoethanol and electrophoresis on sodium dodecyl sulfate-urea polyacrylamide gels, both the 7200 dalton rabbit immunoreactive relaxin-like polypeptide and porcine relaxin migrated as a lower molecular weight protein. These results suggest that rabbit relaxin, like pig, rat, shark, and human relaxin, consists of two chains linked by disulfide bonds. At the light microscopy level, immunohistochemical staining with guinea pig antiporcine relaxin serum indicated that relaxin was located in the syncytiotrophoblast cells of the placental labyrinth of day-23 and day-30 pregnant rabbits. The syncytiotrophoblast cells from day 16 of pregnancy did not stain for relaxin.
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PMID:Rabbit placental relaxin: purification and immunohistochemical localization. 390 61

Relaxin is an ovarian polypeptide hormone which is present in large amounts in the rat during the second half of gestation. During this period, blood pressure declines markedly, especially in spontaneously-hypertensive rats (SHR). To test the hypothesis that relaxin might be implicated in this decrease in blood pressure, we infused the hormone in female non-pregnant rats by means of an osmotic mini pump. Our results show that intravenous infusion of purified rat relaxin (1.8 micrograms/day) markedly reduced systolic blood pressure for at least 5 or 6 days in SHR. This decrease was highly significant from 24 hours after the beginning of the infusion and remained significant after 5 days. Rat relaxin was ineffective in control Wistar-Kyoto rats (WKY). Infusion of purified porcine relaxin (3.0 micrograms/day) also diminished blood pressure in SHR, but the effect was less pronounced and developed more slowly, reaching statistical significance on the fourth day of infusion. SHR not receiving relaxin maintained their original systolic blood pressure throughout the experiment. These results indicate that relaxin is involved in the regulation of blood pressure during gestation.
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PMID:Chronic decrease of blood pressure by rat relaxin in spontaneously hypertensive rats. 404 37

Relaxin is a polypeptide hormone, similar in structure to insulin and has been found in the female of all species studied. The corpus luteum of pregnancy is the main source of relaxin in many species but in others the decidua is apparently of greater importance. It has also been found in other tissues; e.g. prostatic fluid, testis and ovary. First discovered and extracted from the corpora lutea of pregnant sows in an impure form in 1926, it was found to relax the pubic ligament of the oestrogen primed guinea-pig. It was named after this action, but has since been found to have many other possible roles, including preparation of the endometrium for implantation, inhibition of uterine activity in early pregnancy, remodelling of the uterine stroma during pregnancy, cervical ripening and the initiation of parturition. Relaxin's main cellular action in pregnancy may be to drive collagen biosynthesis in its target organs, thus facilitating the remodelling of the connective tissue. Due to the impurity of relaxin preparations used in clinical trials until the mid-1970's, the role of relaxin in the human has been in doubt. Porcine and rat relaxins have now been highly purified and their detailed structure is known. Human relaxin awaits adequate isolation, purification and characterization, and is not yet available for laboratory and clinical trials. However, the recent preparation of purified porcine relaxin for clinical trials and the availability of specific radioimmunoassays for this relaxin together with the identification of relaxin receptor sites, are rapidly helping to establish the concept that relaxin is indeed an important hormone both in human reproduction and in other physiological processes.
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PMID:Relaxin--a review. 628 Jun 66

Although relaxin was discovered almost 60 years ago as a hormone that relaxed the pubic symphysis of the guinea-pig prior to parturition, it has only very recently been purified and characterized. Found in all species studied, it is a polypeptide hormone with a similar structural identity to insulin and nerve growth factor. Its main source appears to be the corpus luteum of pregnancy but it is also produced by the male prostate gland and is found in many target tissues such as cervix, myometrium, decidua and breast connective tissue. Its main mechanism of action appears to be the facilitation of remodelling of connective tissue in target tissues to allow the necessary changes in organ structure during pregnancy and parturition. A secondary mode of action, in some mammals at least, is to inhibit myometrial contractility until near the end of pregnancy. Rat and porcine relaxins have been highly purified and the latter relaxin is now being used in human trials where it has been shown to be a cervical ripening agent probably working in sequence with prostaglandins and oestradiol. A human relaxin polypeptide has recently been characterized from the identification of a genomic clone for relaxin and there is evidence that there may be more than one gene for relaxin in the human. Sufficient amounts of synthetic human relaxin for clinical trials should soon be available using recombinant DNA techniques and this important biochemical advance should facilitate specific in vitro and in vivo studies of the role of relaxin in the human. Possible roles for relaxin in the human which merit further investigation include the enhancement of sperm motility and penetration, implantation of the blastocyst, uterine stromal remodelling during pregnancy, the inhibition of premature labour, cervical ripening at parturition and, in the non-pregnant state collagen biosynthesis in disorders of collagen metabolism such as scleroderma and arthritis.
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PMID:The role of relaxin in human reproduction. 632 55

The insulin gene family, comprised of insulin, relaxin, insulin-like growth factors I and II (IGF-I and IGF-II) and possibly the beta-subunit of 7S nerve growth factor, represents a group of structurally related polypeptides whose biological functions have diverged. The IGFs, or somatomedins, constitute a class of polypeptides that have a key role in pre-adolescent mammalian growth (see ref. 4 for review). IGF-I expression is regulated by growth hormone and mediates postnatal growth, while IGF-II appears to be induced by placental lactogen during prenatal development. The primary structures of both human IGFs have been determined and are closely related. A polypeptide highly homologous to human IGF-II is secreted by the rat liver cell line, BRL-3A. As this polypeptide, termed multiplication stimulating activity (MSA), differs from human IGF-II by only five amino acid residues, MSA probably represents the rat IGF-II protein. Using molecular cloning techniques, we have isolated cDNA and chromosomal genes coding for the MSA and human IGF-II precursors, respectively. Our data, presented here, indicate that both MSA and human IGF-II are synthesized initially as larger precursor molecules. The deduced preprohormones both have molecular weights (MWs) of 20,100 and contain C-terminal propeptides of 89 amino acid residues, which we have named E-peptides. The organization of the IGF-II precursor gene is discussed in relation to that of other insulin gene family members.
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PMID:Insulin-like growth factor II precursor gene organization in relation to insulin gene family. 638 22

This review is concerned with a general discussion of the actions of ovarian hormones, including relaxin, a polypeptide hormone, and estrogens and progestogens, which are two types of steroid hormones. Particular emphasis is placed on describing the sites of action and target organ responses induced by the two steroid hormones. A detailed description of estrogen activity in reproductive tract tissue is given as an example of the intracellular mechanism of action of this steroid hormone.
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PMID:Selected biochemical actions of ovarian hormones. 701 17

Relaxin is a peptide hormone which consists of two polypeptide chains that are synthesized as a B-chain/C-peptide/A-chain precursor. We have used the polymerase chain reaction (PCR) to isolate and clone a relaxin-like cDNA from sheep placental RNA. This cDNA and two sheep genomic clones were characterised by nucleotide sequencing. A comparison of the sheep nucleotide sequence with exon II of pig relaxin revealed homology of 72%. The sheep sequence had numerous stop codons in the region corresponding to the C-peptide. Therefore, there is no open reading frame which would include the C-peptide and A-chain regions. Analysis of several animals indicates that the stop codons are not due to an allelic polymorphism and Southern blot analysis of genomic DNA reveals the presence of a single copy gene. The 5' RACE PCR protocol was used to obtain sequence information for the 5' relaxin-like RNA. This analysis reveals that unprocessed precursor RNA is the predominant RNA species in placenta. A small proportion of clones was isolated which contained novel 5' sequences. These sequences mostly appear to be generated from repetitive DNA elements upstream of exon II. No relaxin-like exon I sequence which encodes the B-chain was found after an extensive search of the 5' RACE PCR products. Therefore, this relaxin-like gene does not produce an RNA species in ovary, placenta or endometrial tissue which could give rise to a functional sheep relaxin hormone.
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PMID:A single-copy relaxin-like gene sequence is present in sheep. 768 20

Relaxin is a 6000-d polypeptide, structurally related to insulin and the insulin-like growth factors. Unlike insulin, the structure of which is remarkably well conserved among the vertebrates, relaxin sequences can vary by more than 50% between different species. Despite these large sequence variations, relaxins (with few exceptions) have very similar biologic activities in animal test systems. The reason for this has recently come to light: the receptor binding region of the B chain, in contrast to the rest of the molecule, is highly conserved between species. Relaxin is measured by bioassays employing interpubic ligament formation in mice and guinea pigs, and by inhibition of uterine motility. A more sensitive and efficient bioassay is urgently needed. In women, the target organs for relaxin are the uterine cervix, myometrium, endometrium, and decidua. Other presumptive but unproven targets are the pubic symphysis and sacroiliac joints, mammary glands, and pituitary gland. Circulating relaxin is secreted by the corpus luteum. The placenta, decidua, or both also produce relaxin, which does not enter the circulation but may act in an autocrine or paracrine fashion. hCG is a stimulus to luteal relaxin secretion. Other regulatory factors are poorly defined. Aluteal women are hyporelaxinemic, and yet are capable of normal vaginal delivery of their infants. Local effects of placental or decidual relaxin cannot be discounted in such subjects. Hyperrelaxinemia may occur in women with multiple gestations and ovarian stimulation, and may be associated with increased premature births. Serum relaxin also is elevated in pregnant diabetics, but its role in this condition has not been defined. Clearly, further investigations are needed to delineate the precise role of relaxin in human pregnancy.
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PMID:Relaxin and its role in pregnancy. 778 25

The 6-kDa polypeptide hormone relaxin (Rlx) has been identified in human and bovine milk, and we recently reported its presence in canine milk. We postulated that Rlx might be transferred via suckling to the newborn pups, where, by virtue of its known effects to increase the distensibility of the pelvic connective tissues, it could play a role in causing the excessive laxity of the capsule and ligaments of the coxofemoral joint that precedes the development of hip dysplasia in genetically predisposed animals. Rlx was found in the serum of dysplastic (HD+) bitches for up to 6 wk of lactation, whereas it was detected in the serum of nondysplastic (HD-) bitches for only 1-2 wk of lactation. Rlx concentrations in milk were up to 60-fold greater than in serum. Milk Rlx levels varied markedly, but were highest during the first week of lactation and decreased thereafter. There were no significant differences in milk Rlx concentrations between HD+ and HD- bitches. Although the source of Rlx in milk is unknown, it cannot be the ovary or uterus, since hystero-ovariectomy performed at the time of cesarean section did not eliminate Rlx from milk during subsequent lactation. In serum samples taken from newborn pups before suckling, there were significant quantities of Rlx, demonstrating that the hormone enters the fetus in utero. However, Rlx rapidly disappears from serum of pups prevented from suckling for five hours.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transmission of relaxin from lactating bitches to their offspring via suckling. 814 44

Relaxin is a polypeptide hormone best known for its role in parturition. However, high affinity relaxin receptors have been localized in the rat brain and heart in addition to the uterus. Several lines of evidence also suggest that relaxin may be involved in the regulation of blood pressure, heart rate, and the release of oxytocin and vasopressin. We now show by Northern analysis that a 1-kilobase relaxin transcript is detected in the rat brain as well as the ovary of pregnant rats. Using in situ hybridization, relaxin mRNA is localized in discrete regions of the male and female brains, including the anterior olfactory nucleus, tenia tecta, pyriform cortex, neocortex, and hippocampus. Developmental studies show that relaxin mRNA is present in the 1-day postnatal brain, while relaxin receptors are not detectable until 7 days after birth. The relaxin receptor binding affinity was similar in the developing brains, but there was a steady increase in relaxin binding sites during postnatal days 7 to 29, suggesting that relaxin may play a role in brain maturation. While relaxin mRNA is not detected in the heart, high levels of relaxin receptors are detected in the cardiac atrium as early as 1 day after birth. These atrial receptors remained at similar levels throughout postnatal development, suggesting an important role for relaxin in cardiovascular function.
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PMID:Expression of relaxin mRNA and relaxin receptors in postnatal and adult rat brains and hearts. Localization and developmental patterns. 839 68


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