ABSTRACT
Neuramide (NMD), a substance found in crude preparations of porcine stomach extract, is a viral inhibitor that also has putative immunostimulatory effects. The effects of NMD on stress-hormone (ACTH and prolactin-PRL) release were assessed in in vivo and in vitro studies. In the former, blood levels of corticosterone and PRL were measured in NMD-treated male rats. In vitro experiments were performed to evaluate the effects of NMD and three of its fractions (obtained with high performance liquid chromatography) on ACTH and PRL release from perfused rat pituitary slices. NMD increased plasma corticosterone levels in vivo and produced dose-dependent increases in in vitro pituitary release of ACTH. No effects on PRL secretion were observed in vivo or in vitro. The stimulatory effects on ACTH release were caused by the NMD fraction with a molecular weight of > 5000 < 10000 Da.
Subject(s)
Adrenocorticotropic Hormone/metabolism , Antimicrobial Cationic Peptides , Antiviral Agents/pharmacology , Peptides/pharmacology , Pituitary Gland/drug effects , Prolactin/metabolism , Animals , Dose-Response Relationship, Drug , Male , Pituitary Gland/metabolism , Rats , Rats, WistarABSTRACT
Neuramide, a tissue extract having antiviral action against influenza A virus and immunostimulant action, was analyzed by preparative size-exclusion high-performance liquid chromatography (HPLC) and a low-molecular-weight fraction responsible for the antiviral action was isolated after reversed-phase HPLC. Four fractions having immunostimulant activity were also isolated, as evidenced by their potentiating action in the human lymphocyte proliferation induced by phytohaemagglutinin.
Subject(s)
Adjuvants, Immunologic/isolation & purification , Antimicrobial Cationic Peptides , Antiviral Agents/isolation & purification , Peptides/analysis , Cell Division/drug effects , Cells, Cultured , Chromatography, High Pressure Liquid , Humans , In Vitro Techniques , Influenza A virus/drug effects , Leukocytes, Mononuclear/drug effects , Lymphocytes/drug effects , Methylene Chloride , Molecular Weight , Peptides/chemistry , Peptides/pharmacology , UltrafiltrationABSTRACT
An inhibitor which is active against influenza A virus was found in Neuramide, a complex tissue extract that is used as an anti-herpes zoster virus treatment. Kinetic studies showed that significant inhibition of virus production occurred when the inhibitor was added to infected cultures up to 5 h after virus penetration. Molecular sieving fractionation showed that the antiviral activity was contained in a low-molecular-weight fraction (molecular weight, less than 1,000).
