Holokrines

Holokrines refers to a mode of secretion in exocrine glands where the entire secretory cell disintegrates to release its contents. This process is distinct from other secretion mechanisms like merocrine and apocrine secretion. In holocrine secretion, the cell accumulates the secretory product within its cytoplasm, and upon maturation, the cell membrane ruptures, leading to the release of the product along with the cellular debris. This means that the secreted material is essentially the remains of the entire cell. Once the cell has released its contents, it is destroyed and must be replaced by new cell division.

This type of secretion is characterized by the presence of lipid droplets and other accumulated products within the cells prior to their rupture. The sebaceous glands, which are responsible for producing sebum (an oily substance that lubricates the skin and hair), are the primary example of holocrine glands in mammals. Other examples include the meibomian glands of the eyelids and the glands of Zeis. The regeneration of the secretory cells in holocrine glands is continuous, ensuring a constant supply of the secreted product. The rate of regeneration can be influenced by various physiological factors.