CJC1295-no-DAC

CJC-1295 无 DAC——综合研究概况

1. 产品概述和分子延伸

CJC-1295（不含药物亲和复合物，专业名称为 Mod GRF 1-29，即修饰型生长激素释放因子 1-29）是一种高度精密的内源性生长激素释放激素 (GHRH) 合成类似物。其结构为 29 个氨基酸的肽，代表天然 GHRH(1-44) 的完整功能性截短核心片段。Mod GRF 1-29 的显著特征在于对原始 GRF(1-29) 链中四个特定氨基酸位点进行了策略性修饰。与含有药物亲和复合物 (DAC) 的 CJC-1295 不同，后者通过药物亲和复合物与血液蛋白结合，实现多日激活，而 Mod GRF 1-29 则明确地省略了 DAC 模块。这种刻意省略使得该肽能够精确模拟天然脉冲式生理生长激素释放模式，防止受体脱敏和下调，同时提供优化且高度可控的研究窗口。

2. 高级作用机制（MOA）

靶向垂体生长激素释放激素受体激动剂：Mod GRF 1-29 是一种直接、高亲和力激动剂，作用于位于垂体前叶生长激素细胞上的生长激素释放激素受体。结合后，它刺激腺苷酸环化酶途径，增加细胞内环磷酸腺苷 (cAMP) 和钙离子浓度，从而触发储存的生长激素 (GH) 的胞吐作用。

氨基酸优化以抵抗酶切：天然GRF(1-29)在体内会被普遍存在的二肽基肽酶IV (DPP-IV)迅速灭活。修饰型GRF 1-29引入了四个关键的结构取代：Tyr1替换为D-Ala1，Ala2替换为D-Ala2，Asp3替换为D-Asp3，以及Asn8替换为D-Asn8（或根据具体的生产参数进行类似的稳定化修饰）。这些修饰保护肽链骨架免受快速切割，将其结构半衰期从不足5分钟延长至约30分钟，使其能够达到完全的受体饱和。

Synergistic Amplification with GHRP/GHS Modules: Because Mod GRF 1-29 acts exclusively on the GHRH pathway, its biological action is heavily dependent on endogenous somatostatin (GH-inhibiting hormone) levels. When utilized in research models alongside a Growth Hormone Secretagogue (GHS) or Growth Hormone Releasing Peptide (GHRP)—such as Ipamorelin or GHRP-2—the combination acts synergistically. The GHS suppresses somatostatin and initiates a GH pulse, while Mod GRF 1-29 amplifies the height and volume of that specific pulse, yielding a profound, natural metabolic discharge.

3. Chemical Composition and Specifications

Molecular Formula: C152H252N44O42

Molecular Weight: 3367.97 g/mol

Amino Acid Sequence: Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Syr-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH2 (with variations maintaining the four core protective modifications)

Product Specifications: High-purity lyophilized sterile cake/powder (HPLC purity greater than 99 percent), devoid of structural truncation fragments or manufacturing trifluoroacetic acid (TFA) residues.

4. Core Scientific Research and Data Insights

A. Pulsatile Growth Hormone Release and Receptor Desensitization Prevention

The omission of the Drug Affinity Complex makes Mod GRF 1-29 the premier tool for studying natural, physiological hormone kinetics:

Simulation of Natural Somatotrophic Pulses: Unlike continuous GH elevations that disrupt downstream feedback loops, Mod GRF 1-29 induces a rapid spike in circulating growth hormone levels that peaks roughly 15-30 minutes post-exposure and returns to baseline within 60-90 minutes. This behavior perfectly replicates the natural spikes necessary for optimal receptor affinity.

Prevention of Pituitary Pit Desensitization: Because the receptor stimulation is temporary, the anterior pituitary is allowed to replenish its GH stores between research sessions. This prevents tachyphylaxis (rapidly diminishing response to a drug), ensuring that the somatotroph cells maintain long-term sensitivity to the GHRH analog over extended, multi-week longitudinal observation periods.

B. Cellular Nitrogen Retention and Lean Tissue Accretion

The downstream elevation of Growth Hormone and Insulin-like Growth Factor 1 (IGF-1) initiated by Mod GRF 1-29 drives prominent structural changes in muscle and connective tissues:

Upregulation of Myofibrillar Protein Synthesis: In vitro cellular models indicate that the peptide enhances intracellular nitrogen retention within bone marrow and muscle tissue. It activates the mTOR signaling cascade, accelerating tranion pathways responsible for repairing micro-tears and building structural lean mass.

Connective Matrix Protection: Mod GRF 1-29 promotes systemic collagen production, increasing structural thickness and tensile strength in ligaments, tendons, and cartilage linings, which enhances general skeletal integrity in animal models.

C. Selective Adipocyte Lipid Mobilization and Beta-Oxidation

Mod GRF 1-29 通过建立短暂但有效的生长激素优势窗口，改变皮下和内脏脂肪库的代谢行为：

激素敏感性脂肪酶 (HSL) 的激活：短暂的生长激素脉冲启动下游脂肪分解途径，驱动白色脂肪组织内 HSL 的磷酸化。这促使储存的甘油三酯水解为游离脂肪酸和甘油，为细胞β-氧化做好准备。

转向以脂肪为基础的燃料动力学：动员脂质的突然涌入抑制了细胞对葡萄糖的吸收，促使研究模型优先利用脂肪储备进行即时能量消耗，从而导致总体体脂百分比稳定、逐渐下降，而不会损害瘦骨骼结构。