Context: IGF binding protein-1 (IGFBP-1) is essential for IGF-I bioavailability. High levels of IGFBP-1 are encountered in critically ill patients and are a good predictor marker in acute myocardial infarction. The mechanisms responsible for the elevated IGFBP-1 levels in these conditions are still unclear. Interestingly, high levels of vasopressin have been reported in the above-mentioned conditions.
Objective: To study the effect of vasopressin on IGFBP-1 in humans.
Design: Placebo-controlled cross-over study in patients with central diabetes insipidus (CDI) in whom potential interference from endogenous vasopressin secretion is minimized. After a 3-day desmopressin washout period, each patient received i.v. saline on day 1 and desmopressin (3 mug) on day 2. Blood samples were taken after administration, every 2 h during the whole night, starting at 2000 h.
Patients and setting: Fourteen inpatients with CDI in an endocrinology department of a university hospital.
Results: Serum IGFBP-1 increased within 4 h after 1-desamino-8-d-arginine vasopressin (DDAVP) by 375+/-73%, compared with a spontaneous fasting increase by 252+/-46% following placebo administration (P<0.05). No changes were registered in the levels of either classically regulators of IGFBP-1 (insulin, glucagon, and cortisol) or of IGF-I and glucose. The decrease in plasma osmolarity induced by DDAVP did not precede the increase in IGFBP-1.
Conclusions: DDAVP increases serum levels of IGFBP-1. Further investigation is essential to unravel the clinical potential of this interaction in conditions associated with high IGFBP-1 levels.