The smooth ER in all control sections was
typical of rat liver after an overnight fast; it
appeared as a fine lacework of tubular and vesicular
profiles, many of which contained osmiophilic
particles similar to the nascent VLDL in the Golgi
apparatus (Figs. 7 and 9). In experimental sections
the smooth ER was often difficult to identify.
When preservation of ultrastructure and background
density permitted, similar particles could
be identified within cisternae of the smooth ER in