Metabolic support for renal sodium reabsorption.
Our studies demonstrate that renal substrate metabolism may subserve several functions. 1. Substrate oxidation concerns us all, since it provides the support for the internal and external work functions of the kidney. It appears that only certain of the substrates utilized by the kidney have, as their major fate, oxidation. 2. All the substrates participate in the synthesis and turnover of intrarenal constituents. These rates remain to be quantified. In the case of free fatty acids, are their turnover rates through the intrarenal lipid pools proportional to T-Na+? If so, this phenomenon would be part of the Q-O2 minus T-Na+ correlation. Or, is lipid synthesis related to T-Na+ in a nonlinear fashion? 3. Certain substrates (lactate, glycerol, fructose, and probably free fatty acids) are readily interconverted in kidney. This phenomenon is particularly prominent when the blood concentrations of these substrates rise. Glucose or lactate are the major interconverion products, at least in vitro. Are there significant quantities of these or other products synthesized by kidney in vivo? The in vivo observations with 14-C-palmitate suggest, but do not prove, that this is the case. The prime example of a renal substrate interconversion mechanism is, of course, the one so carefully and completely elucidated by Pitts: minus NH3 production from glutamine. The further questions he has raised in this area will undoubtedly keep him and us interested and active for some time to come.
D000818:Animals; D001391:Azo Compounds; D002250:Carbon Radioisotopes; D004396:Coloring Agents; D004285:Dogs; D005230:Fatty Acids, Nonesterified / Q000097:blood / Q000378:metabolism; D005919:Glomerular Filtration Rate; D005947:Glucose / Q000378:metabolism; D049671:History, 18th Century; D007201:Indicator Dilution Techniques; D007668:Kidney / Q000378:metabolism* / Q000502:physiology; D007672:Kidney Cortex / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D008055:Lipids / Q000096:biosynthesis; D009282:Naphthalenesulfonates; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010168:Palmitates / Q000378:metabolism; D010477:Perfusion; D011312:Pressure; D012964:Sodium / Q000378:metabolism*; D014513:Ureter / Q000502:physiology
D001391:Azo Compounds; D002250:Carbon Radioisotopes; D004396:Coloring Agents; D005230:Fatty Acids, Nonesterified; D007773:Lactates; D008055:Lipids; D009282:Naphthalenesulfonates; D010168:Palmitates; D012964:Sodium; D005947:Glucose