HORMONAL MECHANISMS OF GROWTH FAILURE IN MODERATE CHRONIC METABOLIC ACIDOSIS(CMA) WITH NORMAL FOOD INTAKE. 392

Abstract

Hormonal changes in rats subjected to high doses of NH4Cl are similar to those observed in non acidotic rats with similar degree of food deprivation. To assess the effect of CMA with normal food intake on the growth hormone (GH)-insulin-like growth factor (IGF) axis, we compared 3-6 month-old mice with congenital deficiency in carbonic anhydrase II (CAD) to B6AF1 controls (Con). Because of the differences in secretory pattern of GH in rats, genders were analyzed separately. We measured hourly serum GH concentrations(avg±sem) by ELISA using a species-specific antiserum (provided by Genentech), and assessed free serum levels of IGF-1 and IGF-2 by the ratio of the concentration of total IGF-1 or IGF-2 (measured by RIA) to that of high molecular weight IGF-binding protein (IGF-BP3, measured by densitometric analysis of western ligand blots). In male Con (n=6) the number of peak GH levels (defined as > 5 ng/ml) and the average daytime GH concentration were similar to nocturnal values. The average daytime GH concentration and the incidence of GH peaks (8%) in Con males were approximately twice as high as in the other groups. Table