THE PHARMACOLOGIC PROPERTIES OF AN INSULIN-FREE EXTRACT OF PANCREAS AND THE CIRCULATORY HORMONE OF FREY

¹ From the laboratories of the Cottage Hospital, Santa Barbara, California

Insulin-free extract of pancreas causes a transitory fall in blood pressure in the rabbit after intravenous injection. Repeated unit or sub-unit doses, or continuous intravenous infusion, cause a prolonged hypotension probably the result of splanchnic vasodilation. These effects are not attributable to choline or histamine.

In persons with hypertension, intravenous injection causes an immediate transitory "nitrite reaction," and a profoundf all in systolic pressure persisting for approximately one hour.

These effects are not produced if the extract is given by the subcutaneous or intramuscular route.

The coronary arteries of the perfused rabbit's heart are dilated by the extract in dilutions corresponding to a dose in man of 30 to 60 hypotensive units, twice as much as by theophyllin-ethylene-diamine in dilutions of relative strength. The amplitude of cardiac contraction is decreased; the rate, little affected.

The pressor action of adrenalin may be completely inhibited by intravenous injection of the extract when given with it. If given separately, the extract makes the animal refractory to adrenalin for some minutes following the injection. The pressor response is not inhibited by subcutaneous or intramuscular injection of the extract

The circulatory hormone of Frey, as prepared from the urine, has identical properties. It may so decrease the amplitude of contraction of the perfused heart as to overshadow the coronary dilatation which becomes apparent after ventricular fibrillation is induced.

Neither pancreatic extract nor the Frey hormone, on intravenous injection into the guinea pig, cause transitory complete heart-block, a supposedly specific test for adenylic acid and adenosine, which have similar physiologic properties.

It is probable that the active principle of the pancreatic extract and the Frey hormone are identical, and that these preparations do not contain histamine, chloine, adenylic acid, or adenosine, in sufficient quantities to explain their physiologic activity.

The increase in the coronary flow and the antagonism to the pressor effect of adrenalin may explain the salutary influence of extract of pancreas as seen in the treatment of angina pectoris and intermittent claudication.

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				F. R. NUZUM and A. H. ELLIOT PANCREATIC EXTRACT IN THE TREATMENT OF ANGINA PECTORIS AND INTERMITTENT CLAUDICATION Arch Intern Med, June 1, 1932; 49(6): 1007 - 1018. [Abstract] [PDF]