STIMULATORY EFFECTS OF STARFISH SAPOGENINS (ASTERIAS-AMURENSIS AND LETHASTERIAS-NANIMENSIS CHELIFERA) ON MOLLUSCAN HEART (SPISULA-SACHALINENSIS)

Sapogenins from the starfish Asterias amurensis and Lethasterias nanim ensis chelifera, 5 alpha-pregn-9(11)-ene-3 beta,6 alpha -diol-20-one, 5 alpha-cholest-9(11)-ene-3 beta,6 alpha-diol-23-one, 5 alpha-cholesta -9(11),24(25)-diene-3 beta,6 alpha-diol-23-one, (20E)-5 alpha-cholesta -9(11),20(22)-diene-3 beta,6 alpha- diol-23-one and 24 xi-methyl-5 alp ha-cholesta-9(11),20(22)-diene-3 beta,6 alpha-diol-23-one, stimulated the contractile force of the heart of the mollusk Spisula sachalinensi s at concentration of 5 x 10(-5) M. Ouabain, a specific inhibitor of N a+,K+-ATPase, at concentration of 5 x 10(-5) M had no effect on this p hysiological model. Starfish sapogenins of the cholestane series moder ately inhibited rat brain cortex Na+,K+-ATPase and decreased Ca2+ infl ux into Ehrlich carcinoma cells. In contrast, pregnane asterogenin ast erone did not inhibit Na+,K+-ATPase and increased the influx of Ca2+ i nto cells. These effects were not the result of cell membrane damage, because none of the compounds tested have hemolytic activity. (C) 1998 Elsevier Science Inc. AU rights reserved.