BIOL 031 Lecture Notes - Lecture 22: Adipose Tissue, Thyroid, Glucagon
Document Summary
Many peptide hromones are often synthesized as larger proteins= prohormones. Must be cut and spliced together to be active. A target cell is usually responsive to several different hormones: hormones may be antagonistic, synergistic, or permissive, how a cell responds depends on the commination of all hormones. Synergistic effects occur when 2 or more hormones work together to produce a particular effect. Effects may be additive, as when epinephrine and norepinephrine each effect the heart in the same way. Effects may be complementary, as when each hormone contributes a different piece of an overall outcome: for example: producing milk requires estrogen, prolactin, and oxytocin. Permissive effects occur when one hormone makes the target cell more responsive to a second hormone. Exposure to estrogen makes the uterus more responsive to progesterone. Antagonistic effects occur when hormones work in opposite direction. Insulin and glucagon both affect adipose tissue: insulin stimulates fat storage, glucagon stimulates fat breakdown.