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SummaryMeasurements of the rate of fat uptake by the intestinal lymphatics showed that when dogs were fed 25 g of olive oil by mouth the total lipids in the thoracic duct lymph remained elevated above fasting levels for more than 24 hours. When the olive oil was introduced directly into the duodenum, the lymph was cleared of excess lipid in 13 hours. That the excess lipid in postcibal lymph probably represents fat which has been directly contributed by absorption from the intestine was shown by the failure to observe a significant increase in thoracic duct lymph lipid content in response to infusing a large volume of milky chyle intravenously. These results suggest that absorption of fat continues for more than 24 hours after its oral administration and is associated with a slow and prolonged delivery of fat by the stomach into the upper intestine. Stomach-fed dogs returned a significantly higher percentage of the fed fat in the lymph in 24 hours than did duodenum-fed dogs suggesting that the retention of...

Die Endothelschicht von doppelt unterbundenen Abschnitten der A. carotis des Kaninchens wird 3 Tage nach der Unterbindung und Injektion von Intralipid (kunstliche Fett-Emulsion) in das Lumen elektronenmikroskopisch untersucht. Die kunstliche Hyperlipamie zusammen mit Hypoxie erzeugte eine starke Aufnahme von Fett in Form von intrazellularen Tropfchen, die viel elektronendichter waren als die ursprunglichen Intralipid-Partikel. Ein morphologischer Hinweis auf den Mechanismus der Fettaufnahme wurde nicht gefunden.

A method is described for measuring the uptake of neutral fat by the perfused rat liver in vitro. The rate of fat uptake by the isolated liver was influenced by the endocrine balance of the animal at the time the organ was removed. Livers from female rats had a significantly greater rate of fat uptake than livers from males. The rate was markedly increased by fasting and by alloxan diabetes. Insulin reduced the fat uptake of the diabetic liver when the hormone was administered to the animal, but was ineffective when added directly to the perfusion fluid. The results suggest that the rate of uptake of neutral fat by the liver is under direct hormonal control.

The effect of adrenocortical and anterior pituitary hormones on the uptake of neutral fat by the perfused rat liver has been investigated. It was observed that adrenalectomy increased the rate of fat uptake. Cortisone treatment of adrenalectomized animals reduced the rate of fat uptake to that of the normal fed state. Cortisone and hydrocortisone administered in vivo, or added to the perfusion fluid in vitro, reduced the rapid rate of fat uptake resulting from 48 hours of fasting. Hydrocortisone administered to normal fed rats did not depress the rate of fat uptake. The administration of crude anterior pituitary extracts to the normal fed animal significantly increased fat uptake. Hypophysectomy increased the rate of fat uptake. Administration of growth hormone to the normal fed animal 3–8 hours prior to killing, or added to perfusion fluid in vitro, increased the rate of fat uptake.

Since Hahn's observation of the postalimentary lipemia clearing actIvity following the injection of heparin, physiological, biochemical and clinical significances of the postheparin lipoprotein lipase have been well clarified. The presence of the endogenous lipoprotein lipase in human blood, which was at first doubted, has been repeatedly confirmed2∼8. Recent papers9,10 described elevated endogenous lipoprotein lipase activity in patients with essential hyperlipemia after ample fat uptake. In this preliminary report, changes of the lipoprotein lipase activity during oral glucose tolerance test is illustrated.

Summary Thirteen Holstein cows at various stages of lactation and levels of production were milked at 2-hr. intervals with the aid of oxytocin. It was shown that the average daily milk production was increased and that the fat per cent in milk was reduced for the high producers (average daily production: 60.6 lb. milk) during the 2-hr. milking. Following return to twice-a-day milking, the milk production returned to normal, but there was an over-compensatory increase in fat per cent. The moderate producers among the cows (average daily production 39–43 lb. milk) did not show any significant changes in milk production, fat production, or fat per cent. It is concluded that the rate of milk secretion is not altered significantly for moderate producers on changing from twice-daily milking to 2-hr. milking for short total periods. The response of the high producers is explained on the basis of the effects of intramammary pressure on fat uptake by the mammary gland and on the rate of milk secretion.

SUMMARY— Frozen par-fried French-fry cuts allowed to thaw and held several hours before being finish-fried lost more weight (due to loss of moisture) and absorbed more fat than it not held. The yield of finished product decreased about 7% and fat uptake increased about 25% when par-fries were held for 3 days at 50°F. Smaller but economically significant changes occurred in only 1-1/2 hr at this temperature or in 5 hr at 40°F. The rate of the change in par-fries which causes lower yields and greater fat absorption increases with increasing temperature. The time course of the change at 50°F is similar to that of starch retrogradation in par-fries but the rote of retrogradation decreases with increasing temperature; therefore, these appear to be unrelated phenomena. There is no combination of time and temperature for frying par-fries from the thawed state which is equivalent in all respects to a given combination for frying them from the frozen state.

1. 1. Mesenteric adipose tissue when incubated in stearate-1-14C enriched medium was found to take up fatty acid from the medium. 2. 2. The uptake was dependent upon the nutritional state of the animal from which the tissue was obtained. It was found to be lowest in the “starved” and highest in the “refed” animals. Tissues from normally fed animals exhibited intermediary values. 3. 3. The uptake was found to be proportional to the fatty acid concentration. 4. 4. Most of the fatty acids assimilated by the “refed” tissues was found inside the tissue in a bound form, unseparable from the triglyceride fraction. Esterification was found to be much reduced in starved tissue. 5. 5. 14C-Glycerol was esterified only to a very small extent, and additional glycerol caused no change in the uptake and esterification of fatty acids. 6. 6. The uptake and esterification were almost abolished by M 500 cyanide but were not affected by M 20 fluoride. 7. 7. The significance of the results from the aspect of the mechanism of fat uptake by adipose tissue is discussed.

A 13-year-old girl with diabetic acidosis had lipemia retinalis and massive hyperchylomicronemia ( 19.5 Gm. 100 ml. total lipids) corrected by insulin administration. Fat uptake by embryonic cells in tissue culture using the patient's lipemic serum was very marked and was maximal after heparin administration. Red-cell aggregation could be induced in the retinal vessels at the height of her hypertriglyceridemia while conjunctival red-cell aggregation persisted at lower levels of hyperlipemia. Whole-blood viscosity was actually subnormal during the stage of lipemia. With clearing of the hyperchylomicronemia a pre-β band appeared in the lipoprotein electrophoretic pattern of the plasma, which persisted when blood lipid levels returned to normal. The patient's father, mother and brother had pre-β bands despite normal blood lipid and insulin levels and normal glucose tolerance. The pre-β band disappeared on heparin administration. This pattern may represent a prototype of carbohydrate-induced lipemia.