Tentativeness and fervor in cell biology require negative and positive feedforward control.
End-product feedback regulates early steps in metabolic pathways, affecting activation and the rate of end-product synthesis. Early formation of end-product also modifies later steps in the synthesis of end-product. We designate this form of regulation feedforward. Negative feedback/feedforward by end-products may result in homeostasis, but also in physiologic tentativeness. Positive feedback/feedforward by end-product gives rise to fervid events. Tentativeness and fervor, due to negative and positive feedforward rather than feedback, explain otherwise puzzling aspects of immunology and endocrinology.
Sinclair
N R
NR
Department of Microbiology & Immunology, University of Western Ontario, London, Canada.
Challis
J R
JR
D000818:Animals; D001695:Biology / Q000379:methods*; D002468:Cell Physiological Phenomena; D004702:Endocrine Glands / Q000502:physiology; D005246:Feedback; D005260:Female; D006706:Homeostasis; D006801:Humans; D007107:Immune System / Q000502:physiology; D008954:Models, Biological; D011247:Pregnancy; D012107:Research Design