Exercise-induced microalbuminuria in patients with active acromegaly: Acute effects of slow-release lanreotide, a long-acting somatostatin analog

Recent clinical studies have demonstrated an increase of urinary albumin ex cretion (UAE) at rest in acromegalic patients and, on the other hand, a red uced UAE in patients with growth hormone (GH) deficiency. Physical exercise is known to induce abnormal UAE in patients with diabetes, probably unmask ing early glomerular alterations. The effect of exercise on UAE in acromega ly is not known. Moreover, the effect of acute but sustained GH inhibition in acromegaly on UAE at rest and after exercise has never been studied. The aim of our study was to evaluate the acute short-term effects of slow-rele ase lanreotide (SR-L), a long-acting somatostatin analog, on UAE and alpha 1-microglobulinuria (A-1-M), a marker of renal tubular damage, at rest and after exercise in 7 normotensive patients with active acromegaly and normal renal function (4 males and 3 females; mean age, 53 +/- 3.1 years; body ma ss index [BMI], 27.3 +/- 1.1 kg/m(2)) at baseline and 7 and 14 days after S R-L injection (30 mg). Two of the acromegalic patients were microalbuminuri c at rest, and in other 3 cases, UAE was in the borderline range (10 to 20 mu g/min). At baseline in the acromegalic subjects, we found a significant increase in UAE at rest with respect to 7 normal subjects considered as a c ontrol group. GH and insulin-like growth factor-1 (IGF-1) were also reduced compared with baseline 7 and 14 days after SR-L injection (GH, 13.4 +/- 7. 3 and 13.61 +/- 7 v 18.5 +/- 9.3 mu g/L, P < .05; IGF-1, 230 +/- 53 and 255 +/- 54 v 275 +/- 64 mu g/L). Concomitantly, we observed a significant decr ease of UAE at rest and after exercise and 7 and 14 days after SR-L injecti on as compared with baseline values (27.3 +/- 20.5 and 18.2 +/- 13.7 v 35.3 +/- 12.8 mu g/min, P < .05; exercise, 48.5 +/- 24.1 and 18.6 +/- 6.8 v 68. 3 +/- 39.7 mu g/min, P < .05). A-1-M always remained in the normal range (< 12 mg/L) both at rest and after exercise. We can thus conclude that in acro megaly, submaximal exercise induces abnormal increases in microalbuminuria. We hypothesize that this phenomenon may be due to the functional glomerule r involvement. SR-L can significantly reduce UAE at rest and after exercise in the short-term in acromegaly, probably via a decrease in circulating GH levels. Copyright (C) 2000 by W.B. Saunders Company.