Table 2.

Metabolic pathways significantly enriched with increasing insulin concentrations. P-values are FDR adjusted. Metabolites included in each pathway are shown in bold when significantly contributing to the test result. The direction of association is indicated by (+) for a positive and (−) for a negative association with insulin. Despite being described as enrichment, variations in both directions are considered in absolute values, so that decreases in metabolite concentrations can result in significantly enriched pathways as well. Moreover, positive and negative associations within a pathway do not cancel each other out

Pathway	Adj. P value	Metabolites
Ammonia Recycling	0.001	Ser (−), Gly (−), Asn (−), His (−), Gln (−), Asp (−), Glu (+)
Glycine and Serine Metabolism	0.001	Ser (−), Ala (−), Gly (−), Met (−), Arg (−), Sarcosine (+), Glu (+)
Carnitine Synthesis	0.001	Lys (−), Gly (−), C0 (−)
Alanine Metabolism	0.002	Ala (−), Gly (−), Glu (+)
Urea Cycle	0.003	Ala (−), Cit (−), Orn (−), Arg (−), Gln (−), Asp (−), Glu (+)
Glutamate Metabolism	0.004	Ala (−), Gly (−), Gln (−), Asp (−), Glu (+)
Arginine and Proline Metabolism	0.004	Pro (−), Gly (−), Cit (−), Orn (−), Arg (−), Asp (−), Glu (+)
Valine, Leucine, and Isoleucine Degradation	0.009	Val (−), Ile (−), Leu (−), Glu (+)
Methionine Metabolism	0.011	Ser (−), Gly (−), Met (−), Met-SO (−), Putrescine (−), Sarcosine (+)
Glucose-Alanine Cycle	0.011	Ala (−), H1 (+), Glu (+)
Lysine Degradation	0.013	Lys (−), alpha-AAA (−), Glu (+)
Aspartate Metabolism	0.018	Asn (−), Cit (−), Arg (−), Gln (−), Asp (−), Glu (+)
Purine Metabolism	0.018	Gly (−), Gln (−), Asp (−), Glu (+)
beta-Alanine Metabolism	0.042	His (−), Carnosine (−), Asp (−), Glu (+)
Histidine Metabolism	0.045	His (−), Carnosine (−), Glu (+)