Hormone structure, receptors and second messenger signalling
Peptide, amine and steroid hormones and how their chemistry sets storage, transport and half-life; the G protein, tyrosine kinase, JAK-STAT and nuclear receptor families with the hormones that use each; and the receptor mutations, toxins and drugs that Paper 1 uses to test them.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Hormone chemistry sets behaviour. Water-soluble peptides and catecholamines act on surface receptors within seconds to minutes. Lipid-soluble steroids and thyroid hormone cross membranes, act on intracellular receptors and change gene transcription over hours.
- Surface receptors fall into four families: G protein-coupled receptors (most peptide hormones), receptor tyrosine kinases (insulin, IGF-1), cytokine receptors using JAK-STAT (GH, prolactin, leptin, EPO) and guanylyl cyclase receptors (ANP, BNP).
- Gs raises cAMP, Gi lowers it and Gq releases intracellular calcium.
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Sources
- Williams Textbook of Endocrinology (15th ed.)Elsevier (Melmed, Auchus, Goldfine, Rosen, Kopp, 2024), 2024
- Guyton and Hall Textbook of Medical Physiology (14th ed.)Elsevier (Hall and Hall, 2021), 2021
- Weinstein LS, Liu J, Sakamoto A, Xie T, Chen M. Minireview: GNAS: normal and abnormal functions. Endocrinology 2004;145(12):5459-64Endocrinology, 2004
- Mantovani G, Bastepe M, Monk D, et al. Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement. Nat Rev Endocrinol 2018;14(8):476-500Nature Reviews Endocrinology, 2018
- Thiele S, Mantovani G, Barlier A, et al. From pseudohypoparathyroidism to inactivating PTH/PTHrP signalling disorder (iPPSD), a novel classification proposed by the EuroPHP network. Eur J Endocrinol 2016;175(6):P1-17European Journal of Endocrinology, 2016
- Last updated
- 14 November 2026
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