Jack R. Luick
University of California, Davis
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Biochimica et Biophysica Acta | 1955
Max Kleiber; Arthur L. Black; Mary A. Brown; Claude F. Baxter; Jack R. Luick; Floyd H. Stadtman
Abstract 1. 1. Glucose uniformly labeled with 14 C was injected into the jugular veins of two normal lactating dairy cows as single doses of 3 and 6 microcuries per kg body weight respectively. The injected glucose, about 1 gram, amounted to less than 10% of the plasma glucose. 2. 2. Between 30 and 40 minutes after injection the radioactivity of the respiratory CO 2 reached a maximum of 9 microcuries per unit of the relative injected dose (μc injected per kg body weight). 3. 3. During the first 3 hours after injection of uniformly labeled glucose less 14 C appeared in the respiratory CO 2 than was expired during the corresponding period in earlier trials after injection of 14 C labeled acetate, propionate, or butyrate. 4. 4. More than 50% of the 14 C injected as uniformly labeled glucose appeared in the organic constituents of the milk within 10 hours after injection. Over 80% of this 14 C in milk components was found in lactose. 5. 5. In the first milk sample, 3 hours after injection, the specific 14 C activity in the components of the milk decreased in the following order: Lactose → Citrate → Casein → Milk fat. 6. 6. Only about 1% of the carbon transferred from plasma glucose to lactose passed the carbonate pool, 4 to 10% of the carbon transfer to casein followed this path. 7. 7. Three hours after injection the specific 14 C activity in blood glucose had decreased to about 1% of its theoretical level at the time of injection, the latter calculated from injected dose, plasma volume and glucose level in plasma. 8. 8. About 4 5 of the lactose carbon came from carbon in plasma glucose or a pool in rapid exchange with plasma glucose, 1 5 of the carbon in citrate originated from this pool and about 5% of the carbon in casein and milk fat.
Annals of the New York Academy of Sciences | 1956
Max Kleiber; Jack R. Luick
It is fitting that one of the first papers in this monograph should deal with cows because, as regards lactation, the cow, in general, outranks woman. Before we talk of lactation, it is also fitting to talk of pregnancy, since pregnancy precedes lactation and gives lactation its biological significance. C. L. Comar concurred with this point of view, and suggested that he cover the subject of calcium metabolism in pregnancy and that we discuss the calcium metabolism involved in lactation, each of us presenting the work of both our laboratories relating to these respective subjects. We limited the scope of our papers accordingly. The emphasis of this monograph is on calcium, but we started our work with tracers on lactation with phosphorus because P32 was available to us before Ca45. In Oak Ridge, Tenn., Comar and his associates did excellent work on Ca transfer in lactation. Calcium and phosphorus metabolism are, however, so closely related that a joint report on the findings of our two laboratories is quite advantageous. We shall discuss first the requirements of Ca and P for lactation, then the sources in blood of milk Ca and P. We shall show the evidence for the conclusion that a considerable part of the serine phosphate in casein is synthesized from inorganic phosphate in the udder. The relation of blood Ca and P to their source in the feed and in the skeleton will then lead to the final section dealing with the regulation of the calcium supply flow. A high rate of lactation with a corresponding drain of Ca in some cases leads to “milk fever.” We have started to analyze the biochemical conditions involved in milk fever. We are especially interested in the biochemistry of Boda and Cole’s’ prevention of milk fever by feeding low-calcium high-phosphorus diets to cows before they calved.
American Journal of Physiology | 1962
Arthur L. Black; Max Kleiber; Jack R. Luick; Jiro J. Kaneko
C 14 -formate was injected intravenously into two lactating cows or infused into the cistern of a quarter of the udder in a third cow. Several amino acids were recovered from milk protein collected at intervals during a 36-hr period after the C 14 -formate was injected. The amino acids were assayed for C 14 and, in the case of serine and methionine, degraded to establish the intramolecular C 14 distribution. The C 14 was found to be confined largely to the hydroxymethyl carbon of serine and to the methyl carbon of methionine. Relatively little C 14 was present in other positions of these amino acids or in the other amino acids normally synthesized by the lactating cow, showing that formate carbon was confined to a very limited pool during utilization. The incorporation of formate carbon into amino acids apparently takes place largely outside the udder, presumably in the liver.
American Journal of Physiology | 1957
Arthur H. Smith; D. Glenn Reck; Jack R. Luick
Uptake of radiophosphate in the 24 hours after its intravenous injection is much greater in the avian femur (marrow-filled) than in the avian humerus (‘pneumatized’). In animals in which both bones contain marrow, the work of others indicates no difference in the phosphate exchange of these bones. It is concluded that the presence of bone marrow (and perhaps only its vascularity) has a great influence on the phosphate exchange of bone.
Journal of Biological Chemistry | 1952
Max Kleiber; Arthur L. Black; Mary A. Brown; Jack R. Luick; Claude F. Baxter; Bert M. Tolbert
American Journal of Physiology | 1957
Jack R. Luick; James M. Boda; Max Kleiber
American Journal of Physiology | 1960
P. M. Riis; Jack R. Luick; Max Kleiber
American Journal of Physiology | 1961
Jack R. Luick; Max Kleiber
Journal of Nutrition | 1952
G. P. Lofgreen; Max Kleiber; Jack R. Luick
Journal of Biological Chemistry | 1966
Arthur L. Black; Jack R. Luick; Freddy Moller; Rajen S. Anand