cyclic AMP systems

 

The Sutherland hypothesis suggested through extensive research that cyclic AMP is involved as a secondary messenger mediating the effects of peptide hormones, neurotransmitters, neuromodulators, drugs or prostaglandins or cell metabolism is an attractive hypothesis to cell biologists. Most of the phenomena involved in this hypothesis have been confirmed for peptide hormones and therefore the hypothesis is increasingly being used by paraneurologists and students of APUD systems in explaining the effects of cellular hormonal secretions at subcellular levels.

The simple cAMP receptor concept suggests that when the hormones appear on the cell matrix, they bind to specific receptors whose chemical mature has been elucidated for some hormone. The binding to receptor site is rate limiting. The complex so formed (on the cell membrane) causes the activation of the adenylcyclase system which then manufactures cAMP and existing ATP through the catalytic action of Mg2+. cAMP then combines with inactive cytosolic kinase to form active kinase, it also combines with phosphodiesterase which then finally degrades it. The remaining activity within the cell is a cascade phenomena involving the catalysis of non-activated phosphorylase kinase to an active form by cAMP dependent protein kinase. Activated phosphorylase kinase then catalyses the conversion of phosphorylate b to a which causes the synthesis of glycogen. Again, cAMP dependent protein kinase causes the activation of glycogen synthase II to glycogen synthase I.

 

 

 

 

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Creator: Oluwole Ogunranti