Scientific Reference
Semax
Evidence profile: Predominantly preclinical
Semax is a synthetic seven-residue peptide, Met-Glu-His-Phe-Pro-Gly-Pro, built from a short fragment of adrenocorticotropic hormone (ACTH). Its first four residues match positions 4 to 7 of ACTH; the Pro-Gly-Pro tail does not occur there in the hormone and is reported to slow breakdown by peptidases. Short ACTH fragments of this kind are described as lacking the steroid-releasing activity of the full hormone. Semax was developed by Russian researchers, and most of its literature comes from Russian groups working in rats and cell cultures. Controlled human studies are few, many are published only in Russian, and independent replication elsewhere is limited.
Mechanism of Action
No specific receptor for Semax has been identified. Studies in rats have reported higher expression of brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the hippocampus, and other work has examined dopamine and serotonin turnover in the striatum. Transcriptome studies in rat models of cerebral ischaemia describe shifts in the expression of genes tied to immune and vascular processes. Because its core derives from ACTH, an interaction with melanocortin receptors has been proposed, though direct binding evidence is limited. How these separate observations connect has not been worked out.
Molecular Information
- Type: Synthetic ACTH analog (heptapeptide)
- Length: 7 amino acids
- Molecular weight: 813.9 g/mol
- Molecular formula: C37H51N9O10S
- CAS: 80714-61-0