KINE 3012 Chapter Notes - Chapter 8.3: Cell Membrane, Cortisol, Extracellular Fluid
11 Mar 2018
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Nuclear receptors are ligand-modulated transcription regulators: small hydrophobic signal molecules diffuse directly across plasma membrane of target cells & bind to intracellular receptors that are transcription regulators, signal molecules include: Vitamin d: signals bind to intracellular receptor proteins & alter ability of proteins to control transcription of genes. Proteins are both intracellular receptors & intracellular effectors for signal: steroid hormones. Ex: cortisol, steroid sex hormones, vitamin d (vertebrates) made of cholesterol. Cortisol produced in cortex of adrenal glands & influences metabolism. Sex hormones made in testes & ovaries. Responsible for secondary sex characteristics that distinguish males & females. Vitamin d synthesized in skin in response to sunlight. After its converted to active form in liver or kidney, it regulates ca2+ metabolism (promoting its uptake & reducing its excretion in kidney) Retinoids like retinoic acid are made from vitamin a. Have important roles as local mediators in vertebrate development: these sig(cid:374)al (cid:373)ole(cid:272)ules are i(cid:374)solu(cid:271)le i(cid:374) (cid:449)ater.
