SLC38A4 and disseminated peritoneal leiomyomatosis: Secondly, active transport may be reduced in LPD placentas, limited not by ATP availability but perhaps by the reduced expression of placental transporters such as Slc38a2, Slc38a4, potentially regulated by Igf2 and Peg3. Thirdly, a newly characterised response of cultured cells to stress, known as Stress Induced Mitochondrial Hyperfusion (SIMH) [37], that elongates and increases mitochondrial connectivity is able to raise cellular ATP [38].