MurrayF. Brennan

Blood Cell and Plasma Amino Acid Levels Across Forearm Muscle During a Protein Meal

To elucidate the role of blood cells in amino acid metabolism, substrate balance across the forearm was studied in a nitrogen-depleted subject fed 200 gm. of meat. After ingestion of the meal, there was the expected outpouring of amino acids from the splanchnic bed into the general circulation. Both cell and plasma levels of most amino acids in arterial blood increased rapidly. Whole blood arterio-deep venous amino acid differences frequently differed from that of plasma. In conclusion, it appears that both blood cells and plasma transport amino acids from the splanchnic bed to the periphery and that both participate actively in the deposition of amino acids in the forearm of the subject studied.

Studies of Glucagon Secretion in Pancreatectomized Patients

Intravenous arginine infusions were performed in two totally pancreatectomized patients and two age/sex-matched normal subjects. Plasma glucagon concentrations did not increase in the pancreatectomized patients, whereas a four- to sixfold rise of the glucagon levels following arginine administration was seen in the control subjects. Measurements of plasma glucagon-like im-munoreactivity revealed no difference between normal and pancreatectomized subjects. The data suggest the absence of a significant number of normally functioning alpha cells in extrapancreatic sites.

Amino acid levels across normal forearm muscle: Whole blood vs. plasma☆

Abstract The role of human blood cells in interorgan amino acid flux has come under scrutiny. The cells have previously been thought to be inert in amino acid transport; however, evidence has recently become available attributing to the cells an active role in amino acid metabolism. In order to assess the implications of these findings with respect to basal calculations of protein mobilization and utilization, whole blood and plasma arterial and deep venous amino acid levels and arterio-deep venous differences across the forearm of 8 normal subjects were determined. Four of these subjects were then fed 200 g of broiled ground sirloin. Paired arterio-deep venous blood samples were obtained for determination of whole blood and plasma glutamine levels at 1, 2, 3 and 4 hr. It was found that in the basal state, plasma arterio-deep venous differences were considerably greater than whole blood arterio-deep venous differences suggesting a minimal role played by the cells. Following the ingestion of the meal, whole blood arterial and deep venous glutamine levels did not change significantly. However, compartmental analysis revealed a decrease in arterial blood cell glutamine and an increase in arterial and deep venous plasma glutamine. It was concluded that both plasma and whole blood amino acid determinations should be performed in studies concerned with interorgan amino acid transport.