Pharmacologically active constituents of the cockroach corpus cardiacum: Resolution and some characteristics

Abstract

By means of paper chromatography, chymotrypsin digestion, and bioassay, six to nine active substances were detected in extracts of the corpus cardiacum of Periplaneta americana (Linnaeus). These substances affect the cockroach foregut, hindgut, heart, nerve cord, and hemolymph trehalose levels with some degree of specificity. Three components, designated as Factors P 1, P 2 and P 3, are responsible for most, if not all, of the heart and hindgut activity of crude extracts of the corpus cardiacum. These three substances appear to be peptides. They are heat-stable, chymotrypsin-sensitive and dialysable; their rates of dialysis differ. Factor P 1, according to its rate of dialysis, is the largest of the three peptides and is equally active on the hindgut and heart. Two smaller peptides, Factors P 2 and P 3, are specific activators of the hindgut and heart, respectively. Isolated “intact” corpora cardiaca retained Factors P 1 and P 2, quantitatively, during a 60-minute incubation in isotonic and hypertonic salt solutions, but not in hypotonic solutions. Considerably less of these peptides were retained within the “intact” gland during incubation in glucose or sucrose solutions. Thus, retention of the peptides under these conditions was salt-dependent; this salt requirement appeared to be non-specific. Factors P 1, P 2 and P 3 were associated with a particulate fraction in homogenates of corpora cardiaca. Hypotonic solutions disrupted this association. Unlike the retention of these factors by the “intact” gland, this association does not appear to be salt-dependent. Finally, transplanted corpora cardiaca were gradually depleted of their hindgut-active peptides.