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Types of Hormones

JoVE 10988

Hormones can be classified into three main types based on their chemical structures: steroids, peptides, and amines. Their actions are mediated by the specific receptors they bind to on target cells.

Steroid hormones are derived from cholesterol and are lipophilic in nature. This allows them to readily traverse the lipid-rich cell membrane to bind to their intracellular receptors in the cytoplasm or nucleus. Once bound, the cytoplasmic hormone-receptor complex translocates to the nucleus. Here, it binds to regulatory sequences on the DNA to alter gene expression. Peptide hormones are made up of chains of amino acids and are hydrophilic. Hence, they are unable to diffuse across the cell membrane. Instead, they bind to extracellular receptors present on the surface of target cells. Such binding triggers a series of signaling reactions within the cell to ultimately carry out the specific functions of the hormone. Amine hormones are derived from a single amino acid, either tyrosine or tryptophan. This class of hormones is unique because they share their mechanism of action with both steroid as well as peptide hormones. For example, although epinephrine and thyroxine are both derived from the amino acid tyrosine, they mediate their effects through diverse mechanisms. Epinephrine binds to G-protein coupled receptors present on the surface of the plasma

 Core: Biology

Serial Dilutions and Plating: Microbial Enumeration

JoVE 10507

Source: Jonathan F. Blaize1, Elizabeth Suter1, and Christopher P. Corbo1
1 Department of Biological Sciences, Wagner College, 1 Campus Road, Staten Island NY, 10301


Quantitative assessment of prokaryotes can be onerous given their abundance, propensity for exponential proliferation, species diversity within a population, and specific …

 Microbiology

Chromatin Interaction Analysis with Paired-End Tag Sequencing (ChIA-PET) for Mapping Chromatin Interactions and Understanding Transcription Regulation

1Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, 2A*STAR-Duke-NUS Neuroscience Research Partnership, Singapore, 3Department of Biochemistry, National University of Singapore, Singapore

JoVE 3770

 Biology

Enhanced Reduced Representation Bisulfite Sequencing for Assessment of DNA Methylation at Base Pair Resolution

1Department of Medicine, Weill Cornell Medical College, 2Institute for Computational Biomedicine, Weill Cornell Medical College, 3Department of Physiology and Biophysics, Weill Cornell Medical College, 4Department of Pathology, University of Michigan

JoVE 52246

 Biology
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