Of the unsaturated fatty acids, oleic acid is the most widely encountered in nature. As previously noted, monoethenoids have a group of 9 carbons either toward the carboxyl or methyl end of the molecule. With the double bond between C9 and C,10 in a molecule of 18 carbons, oleic acid appears to satisfy both tendencies, which could account for the ubiquity of this acid.

Oleic acid circulates, is deposited as reserve, and is used as caloric metabolite especially when bound to glycerol. In considerably lesser amounts, when bound to glycerophosphoric acid, it takes part as a phospholipid in the formation of the lipidic system of the organism. It is only slightly active in oxidation processes. For this reason, large doses are necessary to influence abnormal processes at different levels. Even then, only limited changes are induced. In in vitro studies, oleic acid produces no changes in bacteriophages. A certain influence is noted for receptivity of dermotrope viruses. Injected subcutaneously in rabbits, oleic acid induces in the skin, at the site of injection a zone of low receptivity for smallpox virus. Oleic acid has a reduced effect upon microbes, causing the appearance of some gram negative individual forms of Bac. subtilis, for instance. Mixed directly with blood, oleic acid induces hemolysis. When plasma is treated with this acid, and then mixed with red cells, the influence exerted upon red cells because of the small amount of acid fixed upon plasma, is reduced. Although oleic acid may influence the pH of the second day wound crust, causing an increased local alkalosis (Fig. 119), its influence upon pain is almost nil. Little or no change is seen in standardized radiation wounds in animals treated with the acid. A limited influence can be observed on tumor growth by using the technique of dipping transplants for successive generations. Use of a 10% solution of oleic acid in tricap rylin before grafting, repeated for successive generations, impairs growth of Ehrlich mouse adenocarcinoma after the sixth or seventh generation in some experiments, even later in others. Negative passage takes place between the eighth and tenth graft. Under the same condition, very little or no changes are noted in other tumors, and no changes are seen in tumors in animals treated with this acid even though changes have been reported by some authors. (124) Suspensions of cells of different organs, treated in vitro with colloidal suspension of oleic acid and injected in animals of the same species, induced no changes with a single injection. Repeated injections after 3 weeks induced lesions in the respective organs.

the constant presence of a change toward more alkaline values

Fig. 119. The second day wound crust pH for oleic acid shows the constant presence of a change toward more alkaline values.

At the organic level, some effects can be obtained by using high doses of oleic acid. For example, to prevent convulsions induced by thiamine chloride, doses as high as several hundred milligrams per 100 gr. of body weight are required and even then this effect is not constantly seen. Systemic changes, recognized through blood and urine analyses, are almost nil, even with large doses of oleic acid. The compound however, does prolong liver regeneration time.

Among the diethenoics, we studied linoleic acid. The caloric activity of the uncombined fatty acid is reduced while constitutional and functional activities are increased. Linoleic and linolenic acid appear to be organizational rather than functional fatty acids because of their preferred bond to glycerophosphoric acid. They are absorbed from the intestines, mainly as phospholipids. No effects upon phage can be seen. The refractivity to smallpox virus induced on rabbit skin is more manifest than for oleic acid. However, the effect upon microbes, such as subtilis, is less evident than for oleic acid. Crenelated red cells, with increased tendency to conglutinate and increased sedimentation rate, are found after linoleic treatment of the blood in vitro. To avoid hemolysis, the acid is not added directly to the blood but to the plasma which is then reunited with the cells. Crenelated cells also appear in vivo in rats injected intraperitoneally with large amounts of this acid, such as 10 cc. of 10% in oil. A definite shift toward alkalosis is found in the second day wound crust pH, which explains the influence seen upon pain. Linoleic acid increases pain of an alkaline pattern and decreases pain of an acid pattern, though only slightly. Only in relatively large doses (2-400 mg./100 gr. animal), does it prevent the convulsions induced by thiamine.

In lesions induced by radiation, the administration of small doses of this fatty acid often produces a favorable healing effect. This effect can be related to the growth stimulating action of essential fatty acids in small quantities. The effect is just the reverse of the unfavorable influence on healing observed when larger doses are administered. An effect upon tumors in animals can be achieved only through repeated treatment of successive transplants or through the treatment of successive generations of the host. The effect of repeated injections of tissue cells treated in vitro with a suspension of linoleic acid was more manifest than that obtained with oleic acid. The effect upon the systemic level, although more manifest than for oleic acid, still is limited, even under abnormal conditions. Blood and urinary analyses are only slightly and briefly changed toward the D type of offbalance even when large amounts are administered. Blood eosinophils are decreased and potassium content increased, both only slightly. Body temperature is slightly depressed.

Preparations especially rich in triethenoid linolenic acid were used and no differences between their biological activity and that of linoleic acid could be noted.

We obtained preparations especially rich in arachidonic acid from salmon oil. The caloric contribution of this acid can be considered almost nil compared to its functional role. It is absorbed, circulated and stored, principally as esterifying sterols. Although this acid is present in the body in relatively small amounts, it represents more than 25% of the fatty acids of the adrenals. In view of the highly functional role of the adrenals, it is logical to suppose that arachidonic acid's abundance in the glands is not merely coincidental. A liberation of this acid, together with other higher polyunsaturated fatty acids from the adrenals appears to take place during the first phase of the diphasic defense phenomenon. In the first minutes following a noxious intervention inducing shock, a depletion of fatty acids in the adrenals occurs, coinciding with increased amounts in blood.

Besides their role in the defense mechanism, the adrenal fatty acids seem to intervene in normal physiology. Successive liberations seem to occur, alternating with liberations of sterols, as well as corticosterones. Together, these produce the diphasic oscillations which characterize the physiologic dynamic balance.

Preparations rich in arachidonic acid seem to act at different levels. No manifest influence upon phages is observed. The influence upon smallpox viruses and upon microbes is similar to that of the linoleic preparations. The in vitro and in vivo effects upon red blood cells, such as crenelation, conglutination and increased sedimentation rate, are more manifest than for linoleic acid. Leucopenia also is seen. The effects upon the pH of the second day wound crust and upon pain are, however, the same as for linoleic acid. The intensity of acid pain is reduced while that of alkaline pain is increased. In doses much smaller than for linoleic acid, arachidonic acid preparations are able to prevent convulsions induced by thiamine. But they do not seem to change the evolution of radiation lesions. The influence upon tumors is very similar to that of linoleic acid, and only limited changes are observed after treatment of successive generations, either through the dipping of transplants or through treatment of successive hosts. Organ cells treated in vitro with suspension of this fatty acid were seen to induce changes in the respective organs, if injected twice at 3 weeks interval. Systemic influence is not manifest even under abnormal conditions.

Blood and urine analyses are slightly and temporarily changed toward the pattern of fatty acid predominance.

Continuing these studies, we have investigated polyunsaturated fatty acids with more than four double bonds, particularly clupanodonic acids from cod liver and sardine oils. Most of the studies were made by using the fractions which when brominated are soluble in acetone at a low temperature, i.e., around -63°C. The different fractions obtained were identified through iodine number, neutralization value and spectral analysis after conjugation through treatment with KOH.

All the biological effects upon viruses, microbes, cells, etc., are more accentuated than for linoleic or even arachidonic acid. Changes in red cells and leucocytes are much more apparent. At this point we must emphasize the preference of these fatty acids for red blood cells over plasma both in vitro and in vivo treatments. (Note 2) They have greater effects upon pain than do linoleic and arachidonic acids, reducing pain of an acid pattern and exacerbating pain of an alkaline pattern. The local pH, as determined by second day wound crust measurements, also is shifted toward increased alkalinity. Convulsions induced by thiamine are influenced by much smaller doses than those required with other unsaturated fatty acids. For some preparations with iodine indices around 350, doses as low as 35 mg./100 gr. of body weight are sufficient to prevent convulsions. Changes in the evolution of tumors are more striking with these preparations, especially when the transplants of successive generations are dipped in the preparation. With this technique, negative results are obtained even at the third transplant for Ehrlich mammary adenocarcinoma. An obvious effect is noted on radiation induced lesions, with ulceration increased and healing slowed. The influence upon cholesterol levels in the blood and upon hypertension is greater than for arachidonic acid. The effects upon systemic changes, observed through analyses, are temporary and no greater than for linoleic and arachidonic acids.