Table 1.

Comparison of the effects/functions between the main functional types of estrogens¹

Effect/ function/ action/ characteristic	E1	AE1	E2	AE2
Bind the ERs at the hormone binding site	↑↑2	X	↑↑2	~
Bind the AF1 or AF2 sites of the ERs	X2	↑	X2	~
Bind to mitochondria (and some membranes)	~	~	↑2	↑2
Elicit a direct classic estrogenic response	↑2	X	↑↑2	↑↑2
Induces hypoglycemic effects	~i	↑↑2	↑2	~
Is carried by lipoproteins	↑2	↑↑2	X	↑2
Show anti-oxidative effects	~	~	↑2	↑↑2
Activate the 3C→2C conversion (pyruvate dehydrogenase)	~	↑2	↑↑2	~
Increase mitochondrial oxidative activity	~	~	↑	~
Increase whole body thermogenesis	~	↑2	↑2	~
Show lipolytic effects	X	↑	↔	~
Show lipogenic effects	↑	↓2	↓2	~
Decrease WAT fat mass/ limits fat deposition	↓	↑↑2	↑2	~
Allow the activation of the alternative N disposal pathway	~	~	↑	~
Decrease body protein mass	↔	X2	X2	~

¹Specific early development and pregnancy-related estrogen molecular species and functions not included.

²Shows a coincidence of effect/function for different estrogen types in the same row.

↑: Exerts the effect described; ↓: Exerts an effect opposite to that described; ↔: Variable/not univocal responses; X: Does not exert the effect described; ~: Absent or insufficient information available; E1: Estrone; AE1: Acyl-estrone; E2: 17β-estradiol; AE2: Acyl-E2; ERs: Estrogen receptors; AF1: Activation function site 1 of the estrogen receptors; AF2: Activation function site 2 of the estrogen receptors; WAT: White adipose tissue.