IN VITRO EFFECT OF PARATHYROID GLAND EXTRACT UPON THE ULTRAVIOLET ABSORPTION OF REDUCED COENZYME II (TPNH)

Abstract

SUMMARY Reduced triphosphopyridine nucleotide (TPNH) incubated with parathyroid gland extract (Injection Parathyroid, Lilly & Co.) for 6hr at pH 7·4 and at room temperature exhibits a reduction in u.v. absorption at 340 mμ. No correlation could be shown to exist between this decrease in absorbing capacity of TPNH at 340 mμ and the calcium-mobilizing activity of the extract. Dialysis of the active extract against distilled water or treatment with ethanol-diethyl ether or with formaldehyde resulted in a marked reduction or virtual elimination of biological activity, and in a marked reduction in the ability of the treated preparation to affect the absorbing capacity of TPNH at 340 mμ. Inactivation of the calcium-mobilizing principle of the extract by pepsin resulted in a preparation which retained its ability to affect the u.v. absorption of TPNH. Dialysis of the pepsin-inactivated extract against distilled water or treatment with ethanol-diethyl ether decreased this spectrophotometric effect.