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Overview of Hormone Action

ENDOCRINE PHYSIOLOGY

Steroid Hnrmones Thyroid Hormones Vitamin D

O

Peptide and Catecholamine Hormones

Si gnał generator

Celi membranę

Heterotnmeric C protein

Sccond messengers

----► fcAMP, rCMP, Ca²*,

Tymsine Unasf |p„ diacylglyrerol) actiytty

Rcgulation of mctahnlic pathways, celi growth, etc.

Regulalion of adivitY and ■- mRNA —* conccntration of eniymci and othcr protein*

Autocrine

Effect

Paracrine

Endocrine

Effect

Neurocrine

Effect J. Perkins °I®N

Figurę 8.1 Overview oi Hormone Action_

I lormones are invołved in the process of cell-tocell signaling. Hor-mnnes interact with their targel celi*. via specific hormone-receptor interactiun*. (see Chart 1.2). The receptor may be in the plasma membranę or inside the celi (cyloplasmic or nudcar). The hormone-recep-tor interaction may generale second messengers or regulate gene expression. The effect of the hormone on the r ell may be the result of altered metabolit, pathways (i.e., changes in enzyme acthnty r>r concentrations of enzymes) or changes in celi struciure and growth The lower panel illustrates the diłferent modes of cełMo-cell commu nication.

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