Abstract
Aims/hypothesis. We investigated in normotensive Type I (insulin-dependent) diabetic patients with normoalbuminuria the role of growth hormone-induced IGF-1 in the modulation of renal haemodynamics, Methods. We measured glomerular filtration (GFR) and renal plasma flow (RPF) at baseline and at 24 h after injection of different doses of growth hormone (0.1, 0.2, 0.4 U kg(-1) body weight(-1)) in six patients with normal GFR under a euglycaemic clamp. We also examined a 24-h profile of plasma growth hormone and IGF-1 during usual insulin therapy in two other groups each with seven patients with a lower (from 93 to 114 mi min(-1) (1.73 m(2))(-1)) and higher (from 121 to 146 mi min(-1) (1.73 m(2))(-1)) GFR. Results. Plasma growth hormone concentrations peaked 2 h after its injection and plasma concentrations of IGF-1 peaked about 24 h after the growth hormone injection. There was a significant increase in GFR and RPF 24 h after the highest dose of the growth hormone injection (corresponding to the highest IGF-1 concentration), from baseline values of 115 +/- 24 and 536 +/- 141 mi min(-1) (1.73 m(2))(-1) to 160 +/- 33 and 657 +/- 137 mi min(-1) (1.73 m(2))(-1), respectively (p <0.01 for GFR and p <0.05 for RPF). No differences were observed in the 24-h profile of growth hormone and IGF-1 plasma concentrations between the two groups; growth hormone and IGF-1 concentrations were lower than those obtained after the injection of 0.4 U kg(-1) body weight(-1) of growth hormone. Conclusion/interpretation. These results show that pharmacological growth hormone-induced IGF-1 concentrations are required to modify renal haemodynamics in Type I diabetic patients and suggest that, under the "physiological" conditions of diabetes, IGF-1 has no role as a mediator of glomerular hyperfiltration.
Original language | English |
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Pages (from-to) | 922 - 926 |
Number of pages | 5 |
Journal | Diabetologia |
Volume | 43 |
Issue number | 7 |
DOIs | |
Publication status | Published - 2000 |