Cellular communication and Hormones

Hormones

• chemical signals used to communicated information/needs from one part of the body to another.
• can cause very diverse effects depending on concentrations and type of receptors they bind to.
• help maintain homeostasis
• Three main hormone types
• Steroid Hormones
• Peptide Hormones
• Amine Hormones

• built on a cholesterol foundation ––> the final hormone depends on what enzymes are present.
• ex. the adrenal gland makes cortisol, while the ovaries make estrogen, even though they have the same precursor
• ANALOGY: when life hands you lemons, make lemonade... or lemon pie... or lemon ice cream.... whichever you like best!
• small hormones that can be moved by simple diffusion
• because they are small, they can be made quickly and are not stored for future use.
• hydrophobic
• do not dissolve well in blood, but need a carrier to help them move though it.
• because it can move through simple diffusion, it can bind to nuclear receptors or receptors in the cytoplasm

• built on an amino acid foundation
• hydrophilic
• dissolve well in the blood
• bind to cell membrane receptors
• many of these hormones can often be found in one protein/peptide chain
• ex. insulin and other proteins are synthesized in the same chain, then separated at the end.
• made in advance, then released when needed

• built on a tyrosine or tryptophan foundation
• hydrophobic (thyroid hormones) or hydrophilic (epinephrine).
• Many different types with diverse effects
• catecholamines are stored, but not all amines are. As we said, they are very diverse!