Daily infusions with a chemical commonly associated with feelings of happiness were shown to increase calcium levels in the blood of Holstein cows and the milk of Jersey cows that had just given birth. The results, published ...
Other
Jul 15, 2016
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An ultrasound has confirmed that a giant panda at Atlanta's zoo is pregnant with her fourth cub and will likely give birth later this month, zoo officials said Tuesday.
Plants & Animals
Jul 2, 2013
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The welfare of poultry could be improved by a discovery about how chickens regulate their appetites.
Other
Mar 26, 2013
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(Phys.org)—Paleopathologist Simona Minozzi and her team working at the University of Pisa, have published a paper in the Journal of Clinical Endocrinology and Metabolism describing the skeletal remains of a Roman man from ...
Innovative new technology has been used to identify and profile a novel combination of proteins that may improve treatment for prostate disorders. The study will be published in the April 13th 2012 edition of the Journal ...
Biochemistry
Apr 16, 2012
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Endocrinology (from Greek ἔνδον, endo, "within"; κρῑνω, krīnō, "to separate"; and -λογία, -logia) is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions called hormones, the integration of developmental events such as proliferation, growth, and differentiation (including histogenesis and organogenesis) and the coordination of metabolism, respiration, excretion, movement, reproduction, and sensory perception depend on chemical cues, substances synthesized and secreted by specialized cells.
Endocrinology is concerned with the study of the biosynthesis, storage, chemistry, and physiological function of hormones and with the cells of the endocrine glands and tissues that secrete them.
The endocrine system consists of several glands, all and in different parts of the body, that secrete hormones directly into the blood rather than into a duct system. Hormones have many different functions and modes of action; one hormone may have several effects on different target organs, and, conversely, one target organ may be affected by more than one hormone.
In the original 1902 definition by Bayliss and Starling (see below), they specified that, to be classified as a hormone, a chemical must be produced by an organ, be released (in small amounts) into the blood, and be transported by the blood to a distant organ to exert its specific function. This definition holds for most "classical" hormones, but there are also paracrine mechanisms (chemical communication between cells within a tissue or organ), autocrine signals (a chemical that acts on the same cell), and intracrine signals (a chemical that acts within the same cell). A neuroendocrine signal is a "classical" hormone that is released into the blood by a neurosecretory neuron (see article on neuroendocrinology).
Hormones act by binding to specific receptors in the target organ. As Baulieu notes, a receptor has at least two basic constituents:
Between these is a "transduction mechanism" in which hormone binding induces allosteric modification that, in turn, produces the appropriate response.
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