There are mainly three types of cell signalling:

Endocrine

Exocrine

and

Autocrine signelling

autocrine signalling : the cell automatically signals it self through a chemical that it synthesizes and then respond to .

example : insulin like growth factor secreted within muscle cell .

Matthew Frederick William Gee has written:

'Studies of autocrine VEGF signalling in rhabdomyosarcoma'

disadvantage of in-band signalling

In autocrine signaling, a substance produced by a cell effects that cell, as with cytokines in the immunity system. Endrocrine signaling is a systemic response to a substance.