Deuterium and Bromide Dilution, and Bioimpedance Spectrometry Independently Show That Growth Hormone-Deficient Adults Have an Enlarged Extracellular Water Compartment Related to Intracellular Water

Abstract

GH has a strong influence on body composition. However, the effects of GH deficiency in adults on water compartments are not well understood. Therefore, extracellular water (ECW) and total body water were independently determined by deuterium and bromide dilution and by bioimpedance spectrometry in GH-deficient (GHD) adults and compared to those in controls, matched for age, sex, body weight, and height.The results show that the percent body fat was significantly (P Ͻ 0.05) higher, and total body water and intracellular water (ICW) were significantly lower in GHD adults for males, females, and both sexes combined. ECW was not significantly different between the two groups. ECW/ICW in GHD adults (0.42 Ϯ 0.03) was significantly (P Ͻ 0.01) higher than that in controls (0.39 Ϯ 0.02). There was a significant positive relation between the ECW/ICW ratio and the percent body fat. These results were confirmed by the bioimpedance spectrometry measurements. (J Clin Endocrinol Metab 82: 907-911, 1997) G H HAS, APART from growth-stimulating effects, a strong influence on body composition (1). Recent studies have shown that adults with GH deficiency (GHD) have an increased body fat mass (BF) and a decreased fat-free mass (FFM) (2-5). Sustained high concentrations of GH, like those present in patients with acromegaly (6, 7), result in an relative increased amount of extracellular water (ECW). However, the effects of GHD in adults on water compartments are less well known. Because of the ability of GH to cause sodium retention (8, 9), a relative decrease in ECW is expected to occur when GH levels are reduced compared to that with normal GH levels. Indeed, it has been found that ECW is relatively low in GHD adults (10), and there is one study which indicates that in GHD adults ECW is reduced compared to total body water (TBW) (4). Other studies reveal no difference in relative ECW between GHD adults and controls (11,12). However, the results of the studies mentioned could have been confounded because the methods used did not independently determine TBW and ECW, and control subjects were not matched for age, sex, body weight, and height.The effect of GH administration on water compartments is also not unequivocal. GH treatment was shown to increase ECW in GHD adults (10, 12). However, as it is known that FFM increases with increased GH levels, it is essential to know whether the increase in ECW was relative to that in intracellular water (ICW). In another study in which ECW and ICW were determined independently, strong indications were found that GH treatment in elderly subjects results in an increase in ICW that was associated with a concomitant trend toward decreased ECW (13).To elucidate the controversies concerning the water compartments in GHD adults, we performed a comparative study between GHD adults and controls, matched for age, sex, body weight, and height, in which TBW and ECW were determined independently using deuterium and bromide dilution as well as bioimpedance spectrometry (BIS) for predicting ECW and ICW...

Growth Hormone and Fluid Retention

“…The patients were shown to have decreased extracellular volume (ECV) and total body water and increased fat mass compared with a control group. Similar findings have been reported by others [10, 11, 12, 16], whereas two studies from one group reported normal ECV in GHD patients [14, 15](table 1). …”

Monitoring intracellular, interstitial, and intravascular volume changes during fluid management procedures

“…Bioelectric impedance spectroscopic has proved useful for non-invasive monitoring of inter-compartmental fluid shifts [2, 5, 8, 19, 23, 26, 35, 33, 36, among others.] To date, however, this approach has been limited to two-compartments: intra- and extra cellular volumes.…”

Bioimpedance Spectroscopy for Clinical Assessment of Fluid Distribution and Body Cell Mass

“…41 Only in growth-hormone-deficient patients was BIS shown to accurately estimate TBW and ECW volumes with little bias, as demonstrated by BlandAltman analyses. 33 There have been only a few studies that have analyzed the ability of BIS to quantify changes in fluid volumes. This is considered by some to be a better test of a method's accuracy because the measurement of change removes some of the scaling concerns caused by differences in definitions of fluid compartments.…”

“…A cross-sectional study was conducted by van Marken Lichtenbelt et al 33 to evaluate the accuracy of BIS to measure body water in patients with growth hormone deficiency. They calculated ECW and ICW volumes using the Xitron 4000B software but used specific resistance values for ECW and ICW that had been derived from an independent data set at their laboratory.…”