N and L rat mitochondrial features.

(N1–N2), N mitochondria with lamellar cristae and moderately dense matrix. (L1–L6), L mitochondria exhibited a dense matrix, and a few appeared slightly swollen (white arrows). Small, round mitochondria (L1) were often observed close to others (L2, L3, black arrows). (L3), Two mitochondria coming into contact at two sites (interrupted arrow). (L1–L3), Lipid droplets (ld) close to mitochondria. (L4) Dumbbell-shaped mitochondrion, suggesting on-going fission (black arrow). (L5) Cup-shaped mitochondrion enveloping another mitochondrion (interrupted arrow), suggesting a donut formation. (L6) Asymmetric dumbbell-like mitochondrion close to another mitochondrion (arrowhead) as well as a donut-like mitochondrion (white asterisk).