Editing Parietal cell (section)

===Intrinsic factor secretion===
Parietal cells also produce a [[glycoprotein]] known as [[intrinsic factor]]. Intrinsic factor is required for the absorption of [[Vitamin B12|vitamin B{{sub|12}}]] in the diet.  A long-term [[Vitamin B12 deficiency|deficiency in vitamin B<sub>12</sub>]] can lead to [[megaloblastic anemia]], characterized by large fragile [[red blood cells]]. [[Pernicious anaemia]] results from autoimmune destruction of gastric parietal cells, precluding the synthesis of intrinsic factor and, by extension, absorption of vitamin B<sub>12</sub>. Pernicious anemia also leads to megaloblastic anemia. [[Atrophic gastritis]], particularly in the elderly, will cause an inability to absorb B<sub>12</sub> and can lead to deficiencies such as decreased DNA synthesis and [[nucleotide]] metabolism in the bone marrow.