A Substance with Sympathin E Properties in Spleen Extracts

Abstract

ALCOHOLIC extracts of fresh spleen from cattle contain high amounts, up to 10 µgm. adrenaline equivalents per gm. tissue, of a cardio-accelerator and blood-pressure raising substance, showing the characteristic properties of a sympathomometic catechol compound¹. The active substance was taken up in an ether solution of organ lipids and extracted from this with a 5–10 per cent solution of sodium sulphate. A further purification was attained by treatment with sublimate in alcohol, which left the active substance in the filtrate. The purified extract was found to differ from adrenaline in the following respects. Ergotamine, in a dose which inhibited or reversed the action of adrenaline, was not equally effective in inhibiting the pressor action on the cat's blood-pressure ; the isolated uterus of the virgin or non-pregnant cat was rather less inhibited than by an equipressor dose of adrenaline, and the same applied to the isolated intestine of the rabbit. The relative dilating effect on the iris was considerably greater with adrenaline. Whereas equipressor doses of adrenaline and the spleen pressor substance gave similar catechol reactions with ferric chloride, the fluorescence reaction in alkaline solution² was absent in purified spleen extracts. The active substance in spleen thus conforms better with an amino-base, such as nor-adrenaline, than with adrenaline.