Background: The role of gluconeogenesis from protein in the pathogenesis of
weight loss in lung cancer is unclear.
Objective: Our aim was to study gluconeogenesis from alanine in lung cancer
patients and to analyze its relation to the degree of weight loss.
Design: In this cross-sectional study, we used primed-constant infusions of
[6,6-H-2(2)]-D-glucose and [3-C-13]-L-alanine to assess whole-body glucose
and alanine turnover and gluconeogenesis from alanine in weight-losing (WL
, n = 9) and weight-stable (WS, n = 10) lung cancer patients and healthy co
ntrol (n = 15) subjects.
Results: Energy intake and plasma alanine concentrations did nor differ sig
nificantly among the subject groups. Mean (+/-SEM) whole-body glucose produ
ction was significantly higher in WL than in WS and control subjects (0.74
+/- 0.06 compared with 0.55 +/- 0.04 and 0.51 +/- 0.04 mmol . kg(-1) . h(-1
), respectively, P < 0.01). Alanine turnover was significantly elevated in
WL compared with U'S and control subjects (0.57 +/- 0.04 compared with 0.42
+/- 0.05 and 0.40 +/- 0.03 mmol kg (-1)h(,)(-1)respectively, P < 0.01). Gl
uconeogenesis from alanine was significantly higher,in WL than in WS and co
ntrol subjects (0.47 +/- 0.04 compared with 0.31 +/- 0.04 and 0.29 +/- 0.04
mmol kg(-1) h(-1), respectively, P < 0.01). The degree of weight loss was
positively correlated with glucose and alanine turnover and with gluconeoge
nesis from alanine (r = 0.45 for all, P < 0.01).
Conclusions: Aberrant glucose and alanine metabolism occurred in WL lung ca
ncer patients. These changes were related to the degree of weight loss and
not to the presence of lung cancer per se.