Renal and splanchnic exchange of human biosynthetic C-peptide in type 1 (insulin-dependent) diabetes mellitus.
Biosynthetic human C-peptide or NaCl (154 mmol.l-1) was given intravenously to 13 Type 1 (insulin-dependent) diabetic patients to determine the renal and splanchnic exchange of C-peptide. Catheters were inserted percutaneously into an artery and a renal and hepatic vein. Infusions of C-peptide were given for 60 min at two dose levels (5 and 30 pmol.kg-1.min-1). Insulin was infused throughout the study (0.5 mU.kg-1.min-1) and plasma glucose was kept constant by a variable glucose infusion. The regional blood flows were measured by indicator dilution techniques. In 11 of the 13 patients basal C-peptide levels were not detectable. The arterial steady-state C-peptide concentration was 0.81 +/- 0.10 nmol.l-1 and 2.33 +/- 0.30 nmol.l-1 at the low and high rate infusions, respectively. Renal uptake was 124 +/- 18 pmol.min-1 at the low infusion corresponding to 39% of the infused amount. At the higher dose C-peptide infusion renal uptake increased to 155 +/- 21 pmol.min-1 (p less than 0.05). Urinary excretion of C-peptide was 7 +/- 2 pmol.min-1 at the low dose infusion and increased to 34 +/- 6 pmol.min-1 at the high dose infusion (p less than 0.01). The proportions of infused amount excreted were fairly constant and between 2% and 3%. No net exchange of C-peptide was found across the splanchnic vascular bed. The rate of glucose infusion had to be increased by 35% during the low dose C-peptide, but not during NaCl infusion in order to maintain a constant plasma glucose concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
Sjöberg
S
S
Department of Medicine, Huddinge Hospital, Sweden.
Johansson
B L
BL
Ostman
J
J
Wahren
J
J
D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics / Q000652:urine; D002395:Catecholamines / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D005934:Glucagon / Q000097:blood; D005947:Glucose / Q000008:administration & dosage; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood; D007668:Kidney / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D012965:Sodium Chloride / Q000008:administration & dosage; D013154:Spleen / Q000378:metabolism*
D001786:Blood Glucose; D002096:C-Peptide; D002395:Catecholamines; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D012965:Sodium Chloride; D005934:Glucagon; D005947:Glucose; D009638:Norepinephrine