Glomerular filtration response to acute loading with protein from different sources in healthy volunteers and diabetic patients.

Abstract

To evaluate the effects of acute protein loading on the glomerular filtration rate, albumin excretion rate and concentration of plasma amino acids, ten healthy volunteers and six type 2 diabetic patients with normoalbuminuria were studied before and after eating 0.7 g/kg body weight of tuna fish, boiled egg white, cheese or tofu (bean curd) on separate days. Furthermore, to study the possible role of glucagon, growth hormone, atrial natriuretic peptide and kallikrein in the responses of glomerular filtration rate to protein, these substances were measured before and after ingestion of tuna fish or egg white in six healthy volunteers. In healthy subjects, glomerular filtration rate increased significantly (p <0.01) from 98.1+4.2 ml/min during the baseline period to 129.9+6.6 ml/min after ingestion of tuna fish. No significant differences were seen between glomerular filtration rate before and after ingestion of egg white, cheese or bean curd. No significant differences were observed between the baseline albumin excretion rate and that after loading with any of the four kinds of protein. Plasma concentrations of alanine, glycine and arginine (amino acids known to induce glomerular hyperfiltration) increased to a greater degree after ingestion of tuna fish than after administration of the other meals. Diabetic subjects and healthy volunteers had similar responses. Plasma glucagon and growth hormone concentrations increased after ingestion of the tuna fish meal or egg white. Plasma atrial natriuretic peptide concentration and urinary kallikrein excretion were unaffected by ingestion of these two kinds of protein. These findings suggest that responses of glomerular filtration rate to acute protein loading may differ depending on the protein ingested, and that these reponses may not be directly induced by glucagon, growth hormone, atrial natriuretic peptide or kallikrein. ----diabetic nephropathy ; acute protein loading ; hyperfiltration ; composition of amino acids

Renal, Metabolic, and Hormonal Responses to Proteins of Different Origin in Normotensive, Nonproteinuric Type I Diabetic Patients

“…In contrast, ingestion of egg white or bean curd did not produce increased plasma levels of these amino acids or glomerular hyperfiltration (35,36). In previous studies in healthy volunteers and diabetic patients, the plasma levels of alanine, glycine, and arginine increased significantly only after ingestion of tuna fish, which caused a significant increase in GFR.…”

Atrial natriuretic peptide in Type 2 diabetes mellitus: response to a physiological mixed meal and relationship to renal function

“…Previous studies that have reported raised plasma ANP concentrations involved more heterogeneous populations than ours, 14,18 patients recruited having either Type 2 or Type 1 DM, with or without hypertension, varying degrees of renal dysfunction, and with concomitant use of various medication. 27,28 We chose to study newly diagnosed patients with Type 2 DM with no complications of diabetes, who were normotensive, normoalbuminuric, and on no current medication. By selecting this group of patients some of the confounding variables of other studies have been avoided.…”

Animal Versus Plant Protein Meals in Individuals With Type 2 Diabetes and Microalbuminuria

“…Nakamura et al (14) found, in acute feeding studies, that individuals with type 1 or type 2 diabetes and microalbuminuria did not have a significant change in GFR during 3 h after eating tuna fish or bean curd (tofu). In nondiabetic individuals and individuals with diabetes and normoalbuminuria, there was a significant increase in GFR after tuna fish but not after tofu (12). In a study lasting 4 weeks using normoalbuminuric subjects with type 1 diabetes, Kontessis et al (13) found that GFR, RPF, and median urinary albumin excretion were significantly lower with PP compared with AP diets.…”

“…More problematic is the effectiveness of reducing the amount of dietary protein to at least 0.8 -1.0 g ⅐ kg body wt Ϫ1 ⅐ day Ϫ1 (11) or changing the type of protein. Studies performed in normoalbuminuric individuals with diabetes have suggested that changing the composition of the diet by altering the source of protein from animal to plant, either acutely in the setting of a standard test meal (12) or for up to 4 weeks (13), might produce beneficial renal effects. However, in another acute study, individuals with type 1 or type 2 diabetes and microalbuminuria showed no significant change in renal function when given plant-based protein (PP) versus animal-based protein (AP) (14).…”