Chemical Messengers Secreted by Endocrine Glands. Hormones Travel Through the Blood And

Hormones

Chemical messengers secreted by endocrine glands. Hormones travel through the blood and control the function of cells elsewhere in the body

Steroid hormones
·  made from cholesterol
·  soluble in fat
·  examples: male and female sex
hormones, cortisol
How they work…
1.  Steroid hormone diffuses capillaries à interstitial fluid à target cells
2.  Hormone binds with receptor cells in cytoplasm which create hormone-receptor complex.
3.  Hormone-receptor complex moves into nucleus.
4.  Hormone-receptor complex attaches to segment of chromatin with complimentary shape.
5.  Hormone activates gene.
6.  Gene sends message to ribosomes (in cytoplasm) to begin producing a specific protein. / Protein hormones
§  made up of chains of amino acids
§  soluble in water
§  examples: insulin, growth hormone
How they work…
1.  Protein hormone binds with receptor on cell membrane, creating hormone-receptor complex.
2.  The creation of the hormone-receptor complex activates the production of the enzyme adenylyl cyclase.
3.  Adenylyl cyclase causes cell to convert ATP* (adenosine triphosphate) into cAMP (cyclic adenosine monophosphate).
4.  cAMP works as a messenger and activates enzymes in the cytoplasm to carry out their normal functions.
*ATP is the primary source of energy for the cell.