Lipofuscin (from Greek. Lipos - fat and lat. Fuscus - dark, brown) - golden-brown granular pigment belonging to the group of lipoproteins. The chemical composition is not installed; It is believed to be close to melanin. Lipofuscin does not react to iron, is insoluble in acids and poorly soluble in alkalis, decolorizes with oxidizing agents, is colored with fat and does not turn black when impregnated with silver nitrate.
Normally, lipofuscin is found in the muscle fibers of the heart, skeletal muscles and the intestinal wall (sarcoplasm, near the nuclei), in the liver cells (central segments of the lobules), adrenal gland (reticular zone of the cortex), kidneys (loop of Henle), ganglion cells, epithelium of the testes and seminal tubules. In old age, with atrophic processes, severe chronic debilitating diseases, the amount of lipofuscin in the cells increases.
When cells break down, lipofuscin can be found in the stroma of organs in the form of blocky aggregations. Sometimes an increase in the amount of lipofuscin is observed in healthy young people. It has been established that lipofuscin in cells can quickly disappear and re-accumulate. The origin and functional significance of lipofuscin is unknown. Allow its genetic relationship with hemoglobin. Lipofuscin used to be considered the final product of the exchange, slag (wear pigment), but recently this statement has been revised. There is evidence of a relationship between the amount of lipofuscin and the functional state of the cell and about the active participation of lipofuscin in cellular metabolism. See also Pigments.