A practical reference on 免疫组织: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-04-18 and is reviewed periodically as new material appears.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids, corresponding to the N-terminal fragment of prothymosin alpha. Its sequence begins with acetylation at the N-terminus, a modification that affects stability and receptor interaction. The peptide is acidic, with a calculated isoelectric point near 4.2, and carries no disulfide bonds, so its secondary structure is largely flexible in solution. Molecular mass is approximately 3108 daltons. The native form was first isolated from bovine thymus tissue, while pharmaceutical material is produced by solid-phase peptide synthesis.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic peptide, 28 residues | N-terminal fragment of prothymosin alpha |
| Molecular mass | About 3108 Da | Acetylated form |
| Isoelectric point | Near 4.2 | Acidic peptide |
| Appearance | White to off-white lyophilized powder | Common supplied form |
| Typical storage | -20 °C or below, dry | Solution stability is lower |
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
Thymosin alpha 1 is a short peptide first isolated from bovine thymus tissue in the early 1970s during fractionation work aimed at identifying factors that influence T cell development. It belongs to a family of acidic thymic peptides, and the original preparations contained several components that were later separated by chromatography. The compound is now produced synthetically rather than extracted from tissue, which removes batch variability tied to animal sourcing. Researchers describe it as an immunomodulatory peptide because laboratory studies show effects on several cell types of the innate and adaptive immune systems.
== Physiologie == Androstendion entsteht aus Dehydroepiandrosteron (DHEA) mit Hilfe des Enzyms 3β-Hydroxysteroid-Dehydrogenase. Es wird mittels der Testosteron-17β-Dehydrogenase zu Testosteron reduziert. Umgebaut wird Androstendion durch die Aromatase zu Estron.
=== Physiologische Schwankungen === Die Androstendionkonzentration im Blut unterliegt verschiedenen Schwankungen. Innerhalb eines Tages (zirkadiane Rhythmik) werden die höchsten Werte am Morgen gemessen. Die tageszeitlichen Schwankungen stehen dabei im Zusammenhang mit der Ausschüttung des Hormons ACTH. Bei Frauen ist die Konzentration auch zyklusabhängig: hier werden die höchsten Werte in der Follikelphase des weiblichen Zyklus gemessen. Auch innerhalb des menschlichen Lebenszyklus werden verschiedene Konzentrationen im Plasmaspiegel beobachtet. Bei Feten und Neugeborenen ist der Spiegel hoch, sinkt dann ab und erhöht sich in der Pubertät wieder. Im Erwachsenenalter bleibt er relativ konstant, um dann mit zunehmendem Alter, bei Frauen insbesondere auch nach der Menopause, wieder abzufallen. In der Schwangerschaft ist der Androstendionspiegel erhöht. Auch nach starken körperlichen Belastungen steigt der Androstendionplasmaspiegel.
Hirsutismus Polyendokrinem metabolischem Ovarsyndrom (LH/FSH-Quotient >2) Hyperthecosis ovarii (ovarieller stromaler Hyperthekose), androgen-produzierenden Tumoren adrenaler Hyperplasie Cushing-Syndrom Adipositas virilisierender kongenitaler Nebennierenrindenhyperplasie 3β-Hydroxysteroid-Dehydrogenase-Überschuss Testosteron-17β-Dehydrogenase-Mangel Erniedrigter Spiegel bei:
=== Sport === Die Anwendung von Androstendion zur Leistungssteigerung bei Sportlern oder beim Bodybuilding wurde vom Internationalen Olympischen Komitee sowie von anderen Sportorganisationen verboten. Androstendion steht auf der Dopingliste. Androstendion, dem eine Stimulierung der körpereigenen Testosteronproduktion zugeschrieben wird, gehört in den USA zu den beliebtesten Nahrungsergänzungsmitteln. Verschiedene Studien, unter anderem auch solche von Herstellern, konnten keine dauerhafte Anhebung des Testosteronspiegels, keine Steigerung der sportlichen Leistung und keine Muskelmassezunahme oder sonstige für Sportler vorteilhafte Effekte feststellen. Eine randomisierte Doppelblindstudie von Sonntag u. a. ergab in einem Zeitrahmen von 28 Tagen bei Männern im mittleren Alter keine signifikanten Effekte von Androstendion auf den Testosteronspiegel. Eine Studie mit jungen Männern, die auch Krafttrainingseffekte miteinbezog, fand in 8 Wochen weder eine Steigerung der Krafttrainingseffekte noch solche des Testosteronspiegels. Neben der Wirkungslosigkeit auf Anpassungseffekte im Krafttraining konnte als Folge der Androstendioneinnahme auch eine eventuell ungünstige Verminderung der körpereigenen Testosteronsynthese beobachtet werden. Die Wirkungslosigkeit bezüglich eines sportlichen Nutzens und die unten im Kapitel Nebenwirkungen beschriebenen Risiken ergeben auch unter Auslassung sportethischer Kriterien (Doping) eine ungünstige Kosten-Nutzen-Analyse für die Substitution im Sport.
Sources: de.wikipedia.org
It corresponds to a fragment of the larger protein prothymosin alpha, which is present in many tissues. The isolated 28-amino-acid peptide was originally obtained from thymus preparations, and the pharmaceutical product is synthesized rather than extracted. The term therefore describes both a natural fragment and a manufactured drug substance.
Thymosin alpha-1 is a single defined 28-residue peptide, while the broader family includes unrelated peptides such as thymosin beta-4. The shared name reflects historical isolation from thymus tissue rather than a common structure. Confusion between the two is common in older literature.
No single pathway fully accounts for its reported effects. Several studies describe interaction with innate immune receptors and downstream cytokine changes, but the complete picture is not settled. Open questions remain about which effects occur at physiological concentrations.
It is usually described as an immunomodulatory peptide rather than a classic circulating hormone. No endocrine gland is known to release it as a primary secretory product, and its measured presence in blood is not firmly established.