What is the difference between regulated and constitutive secretion

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Create your free OpenLearn profile. Course content Course content. Intracellular transport Start this free course now. Free course Intracellular transport. Figure 11 Secretory pathways. Molecules in the trans Golgi network are sorted into secretory vesicles either for regulated secretion if they contain appropriate signal sequences or for constitutive secretion if they do not. Proteins for regulated secretion are first assembled in immature vesicles, which mature into secretory vesicles located near the plasma membrane.

Regulated secretion is typically controlled by external signals transduced via cell surface receptors. This example shows a constitutively secreted, membrane-bound molecule and a soluble, secreted molecule, but either type of molecule can be directed down either pathway. Previous 2. Next 2. Print Print. Take your learning further Making the decision to study can be a big step, which is why you'll want a trusted University.

OpenLearn Search website Back to top. Our partners OpenLearn works with other organisations by providing free courses and resources that support our mission of opening up educational opportunities to more people in more places. Wieland et al. Wieland, F. Secretion is not affected by cycloheximide, suggesting that operation of this pathway does not require components supplied by new protein synthesis.

In this report we determined the effects of protein synthesis inhibitor on membrane traffic to the regulated secretory pathway in the mouse pituitary AtT cells. We examined transport of glycosaminoglycan chains since previous studies have shown that these chains enter the regulated secretory pathways and are packaged along with the hormone adrenocorticotropin ACTH. Moreover, in constitutive exocytosis, secretory materials are released continuously. The rate of constitutive exocytosis is well controlled.

This rate depends on their rate of production, which is regulated by transcription and translation. But unlike regulated exocytosis, secretory materials are not released in a regulated manner.

Regulated exocytosis is a more specialized form of exocytosis that is triggered when a cell receives a signal from the outside. Cells carry out regulated exocytosis in response to specific conditions, signals or biochemical triggers. Cells release materials in a highly regulated manner. Secretory materials are first accumulated in secretory vesicles in regulated exocytosis. In this way, cells release cytokines, hormones, neurotransmitters, neuropeptides and other small signalling molecules.

Regulated exocytosis forms the basis for many intercellular signalling processes. There are two pathways of regulated exocytosis. The first pathway primarily secretes polypeptides while the second pathway primarily secretes low-molecular-weight substances. Exocytosis can be constitutive or regulated. In constitutive exocytosis, secretory materials are released continuously.

But, in regulated exocytosis, secretory materials are released into secretory vesicles on-demand via secretagogues and signal transduction.

So, this is the key difference between constitutive and regulated exocytosis. More differences between constitutive and regulated exocytosis are shown in tabular form in the below infographic.