Mitochondrial fatty acid beta-oxidation enzyme that catalyzes the third step of the beta-oxidation cycle for medium and short-chain 3-hydroxy fatty acyl-CoAs (C4 to C10) (By similarity). Plays a role in the control of insulin secretion by inhibiting the activation of glutamate dehydrogenase 1 (GLUD1), an enzyme that has an important role in regulating amino acid-induced insulin secretion (PubMed:20670938). a (3S)-3-hydroxyacyl-CoA + NAD(+) = a 3-oxoacyl-CoA + H(+) + NADH (3S)-3-hydroxybutanoyl-CoA + NAD(+) = acetoacetyl-CoA + H(+) + NADH (3S)-hydroxydecanoyl-CoA + NAD(+) = 3-oxodecanoyl-CoA + H(+) + NADH (3S)-hydroxyhexadecanoyl-CoA + NAD(+) = 3-oxohexadecanoyl-CoA + H(+) + NADH Lipid metabolism; fatty acid beta-oxidation. Homodimer (By similarity). Interacts with GLUD1; this interaction inhibits the activation of glutamate dehydrogenase 1 (GLUD1) (PubMed:20670938). Expressed in liver, kidney, brain, and pancreatic islets. Succinylation at Lys-81, adjacent to a coenzyme A binding site. Desuccinylated by SIRT5. Deficient mice display reduced levels of plasma glucose, elevated plasma insulin levels, increased plasma 3-hydroxybutyrylcarnitine and increased urinary 3-hydroxyglutarate. Islets isolated from knockout mice have increased amino acid-stimulated insulin secretion and higher sensitivity to leucine-stimulated insulin secretion. Belongs to the 3-hydroxyacyl-CoA dehydrogenase family.