Early placenta insulin-like peptide

experimental

Also known as: Insulin-like peptide 4, Placentin, INSL4, Q14641

Early placenta insulin-like peptide (EPIL), also known as insulin-like peptide 4 (INSL4) or placentin, is a member of the insulin/relaxin superfamily encoded by the *INSL4* gene. Its mechanism of action is primarily mediated through binding to the relaxin family peptide receptor (RXFP1 or RXFP2), though specific receptor interactions remain under investigation. EPIL is thought to regulate trophoblast proliferation, differentiation, and invasion during placental development, and emerging evidence suggests it may also modulate osteoblast activity, thereby influencing bone formation and remodeling. Key research findings are limited due to the experimental status of this peptide. Early studies indicate that INSL4 expression is highly restricted to the placenta, particularly in syncytiotrophoblasts, and is upregulated during early pregnancy. In vitro assays have demonstrated its capacity to stimulate cyclic AMP production in target cells, consistent with relaxin-like signaling. Additionally, preliminary data suggest a role in osteoblast differentiation, though direct in vivo evidence is sparse. Only four PubMed-indexed studies currently exist, highlighting the need for further validation. Clinically, EPIL’s potential relevance lies in reproductive medicine and bone health. Dysregulation of INSL4 expression has been associated with placental disorders such as preeclampsia and intrauterine growth restriction. Its osteogenic properties could theoretically inform therapies for osteoporosis or fracture healing, but no clinical trials have been conducted. The peptide remains strictly experimental, with no approved therapeutic applications. For research purposes only — not medical advice.

Key data

Category
Hormonal & Endocrine
Sequence
MASLFRSYLPAIWLLLSQLLRESLAAELRGCGPRFGKHLLSYCPMPEKTFTTTPGGWLLESGRPKEMVSTSNNKDGQALGTTSEFIPNLSPELKKPLSEGQPSLKKIILSRKKRSGRHRFDPFCCEVICDDGTSVKLCT
Molecular weight
15445 g/mol
Research status
experimental
References
4
Tags
uniprot, cleavage-on-pair-of-basic-residues, direct-protein-sequencing, disulfide-bond, hormone, proteomics-identification, reference-proteome, secreted, signal

Mechanism of action

May play an important role in trophoblast development and in the regulation of bone formation

Research & studies

Novel feto-specific mRNA species suitable for identification of fetal cells from the maternal circulation
Prenatal diagnosis · 2001 · PubMed

15 cDNA clones predominantly expressed in placenta were identified via DDRT-PCR.; Seven mRNAs (e.g., epsilon-globin, EPIL, YAP65, osteopontin) were exclusively expressed in placenta.; Eight additional mRNAs showed higher expression in first trimester placenta than in maternal blood cells.; Some markers (e.g., YAP65) were expressed in trophoblast cell lines, while others (e.g., EPIL) were not.

Expression of pro-EPIL peptides encoded by the insulin-like 4 (INSL4) gene in chromosomally abnormal pregnancies
The Journal of clinical endocrinology and metabolism · 2000 · PubMed
Pro-EPIL forms are present in amniotic fluid and maternal serum during normal pregnancy
The Journal of clinical endocrinology and metabolism · 1999 · PubMed

Pro-EPIL levels were higher in amniotic fluid (246 ± 50.8 ng/mL) than in maternal serum (5 ± 2.0 ng/mL) at 12–16 weeks of pregnancy.; Pro-EPIL concentration decreased in amniotic fluid and increased in maternal serum with advancing gestation.; The pattern of pro-EPIL in amniotic fluid resembled that of hCG and its free subunits, while serum pro-EPIL pattern was similar to the free alpha-subunit.; Results suggest pro-EPIL is preferentially secreted by cytotrophoblasts into amniotic fluid and may share regulatory pathways with hCG subunits.

Cloning of a new member of the insulin gene superfamily (INSL4) expressed in human placenta
Genomics · 1995 · PubMed

A new insulin superfamily member, INSL4 (EPIL), was cloned from first-trimester human placenta.; The EPIL peptide has significant structural homology to insulin-like hormones.; The INSL4 gene has two exons and one intron, similar to insulin and relaxin.; INSL4 is expressed in placenta and uterus, and maps to chromosome 9p24.

Frequently asked questions

What is Early placenta insulin-like peptide?

Early placenta insulin-like peptide (EPIL), also known as insulin-like peptide 4 (INSL4) or placentin, is a member of the insulin/relaxin superfamily encoded by the *INSL4* gene. Its mechanism of action is primarily mediated through binding to the relaxin family peptide receptor (RXFP1 or RXFP2), though specific recept

How does Early placenta insulin-like peptide work?

May play an important role in trophoblast development and in the regulation of bone formation

What is the research status of Early placenta insulin-like peptide?

Early placenta insulin-like peptide is currently classified as experimental, with 4 research references on record. This is for research purposes only and is not medical advice.

What is the molecular weight of Early placenta insulin-like peptide?

Early placenta insulin-like peptide has a molecular weight of approximately 15445 g/mol.

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