Use of L-nucleic acid (I) as an intracellular active substance. Independent claims are included for: (1) a procedure for binding an intracellular receptor comprising providing a cell containing at least one intracellular receptor; providing (I); and incubating the cell with (I); (2) a composition comprising (I) and a discharge vehicle; (3) a high mobility group-A (HMGA) binding nucleic acid, comprising a section box A1 and a section box A2, where the section box A1 and A2 are connected together by intermediate section, and particularly comprises GGGCG, GGGUG or GGGAG; (4) a procedure to screen a HMGA-antagonist or HMGA-agonist comprising either providing a candidate-HMGA-antagonist and/or a candidate HMGA-agonist, providing a nucleic acid; providing a test system, which delivers a signal in the presence of HMGA-antagonist and/or HMGA-agonist, and determining whether the candidate-HMGA-antagonist and/or HMGA-agonist; or providing a phase, particularly solid phase immobilized HMGA, providing nucleic acid, introducing a candidate-HMGA-agonist and/or HMGA-antagonist, and determining; (5) a kit to proof HMGA, comprises the nucleic acid; (6) a HMGA-antagonist and HMGA-agonist, are obtained by the process; (7) a complex comprises a HMGA protein and the nucleic acid; and (8) a nucleic acid binding to a transcriptions factor comprises an AT-hooks. ACTIVITY : Cytostatic; Virucide; Antiarteriosclerotic; Antiinflammatory. MECHANISM OF ACTION : High mobility group-A (HMGA) antagonist; HMGA-agonist. The affinity of (I) to bind with HMGA was tested using biological assays. The results showed that (I) exhibited a median inhibitory concentration (IC 5 0) value of 15 nM.본 발명은 세포 내 활성 물질로서의 L-핵산에 대한 용도에 관한 것이다