BSC 2011 Lecture Notes - Lecture 19: Luteinizing Hormone, Aldosterone, Atrazine
24 Aug 2016
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Document Summary
Endocrine system = ductless glands that secrete hormones into extracellular fluid. Exocrine gland = secretes onto epithelial surface (sweat, stomach acid) Endocrine hormone acts on target cells (far away) Paracrine substance (not hormone) acts on neighbor. Autocrine substance (not hormone) acts on self. Peptide hormones (hydrophilic/lipophobic: receptors on membrane, insulin, oxytocin, growth hormone. Steroid (hydrophobic/lipophilic: receptors in nucleus act as transcription factors, must bind to transport proteins to move through body, cortisol, testosterone, estradiol, all derive from cholesterol. Amine (can be either hydrophobic/philic: derive from amino acids, epinephrine and thyroxide (derived from tyrosine) Signal transduction pathway (mechanism from stimulus to response) Single transcription factor could transcribe hundreds of genes. One hormone can have different effects based on the receptor, effector organ, and organism. Organisms can change their response to a hormone by changing their receptors. Upregulation = adding more receptors when hormone secretion is low. Can also be triggered by events such as pregnancy.
