Table 2.

The relationship between placental efficiency measured as gram fetus per gram placenta during natural and experimental conditions and placental expression of glucose and amino acid transporter genes or protein in different species.

	Species	Treatment	Glucose transporters	Amino acid transporters	References
Efficient	Mouse	Naturally small	↑Slc2al, NoΔSlc2a3	↑Slc 38a2	Coan et al. 2008a
placentas	Mouse	Igf2P0+/−	↑Slc2a3, NoΔSlc2a1	↑Slc38a4	Constancia et al. 2005
	Mouse	High fat	↑Slc2a1	↑Slc38a2	Jones et al. 2009
	Mouse	11β HSD−/− Day 15	NoΔSlc2al or Slc2a3	↑Slc38a2 & Slc38a4	Wyrwoll et al. 2009
	Mouse	hTRX-1 overexpression	↑Slc2a1	?	Umekawa et al. 2008
	Rat	Dexamethasone	↑ GLUT1 & GLUT3	?	Langdown & Sugden, 2001
	Guinea pig	Maternal IGF-I	NoΔSlc2a1	↑Slc38a2	Sferruzzi-Perri et al. 2007a
Inefficient	Mouse	11β HSD−/− Day 18	↓Slc2a3	NoΔSlc38a1, a2 & a4	Wyrwoll et al. 2009
placentas	Mouse	Igf2+/−	?	↓Slc38a2,	Constancia et al. 2005;
				↓ System X−AG & y+	Matthew et al. 1999
	Mouse	GH overexpression	?	↓ System X−AG & y+	Matthew et al. 1999
	Rat	Protein restriction	?	↓ SNAT2	Jansson et al. 2006
	Rat	Restricted uterine blood flow	↓Slc2a1	?	Das et al. 1998
	Rat	Undernutrition	↓ GLUT3, NoΔ GLUT1	?	Lesage et al. 2002
	Human	High altitude	↓ GLUT1	?	Zamudio et al. 2006

↑ increased abundance, ↓ decreased abundance, ? no information.