Related topics: breast cancer · women · plants · estrogen · protein

Hair indicates whether wild animals were 'stressed'

While hair analysis has become routine in humans—for example for the detection of prolonged drug or medication abuse—it has been little used in animals to date. Scientists led by Alexandre Azevedo and Katarina Jewgenow ...

For lemurs, sex role reversal may get its start in the womb

Anyone who says females are the 'gentle sex' has never met a lemur. Lady lemurs get first dibs on food, steal their mates' favorite sleeping spots and even attack males, swatting or biting those that annoy them.

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Hormone

Hormones (from Greek ὁρμή - "impetus") are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism. It is essentially a chemical messenger that transports a signal from one cell to another. All multicellular organisms produce hormones; plant hormones are also called phytohormones. Hormones in animals are often transported in the blood. Cells respond to a hormone when they express a specific receptor for that hormone. The hormone binds to the receptor protein, resulting in the activation of a signal transduction mechanism that ultimately leads to cell type-specific responses.

Endocrine hormone molecules are secreted (released) directly into the bloodstream, while exocrine hormones (or ectohormones) are secreted directly into a duct, and from the duct they either flow into the bloodstream or they flow from cell to cell by diffusion in a process known as paracrine signalling.

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