Thyrotropin-releasing factor effect

Many small peptides exert their effects at very low concentrations. For example, a number of vertebrate hormones (Chapter 23) are small peptides. These include oxytocin (nine amino acid residues), which is secreted by the posterior pituitary and stimulates uterine contractions bradykinin (nine residues), which inhibits inflammation of tissues and thyrotropin-releasing factor (three residues), which is formed in the hypothalamus and stimulates the release of another hormone, thyrotropin, from the anterior pituitary gland. Some extremely toxic mushroom poisons, such as amanitin, are also small peptides, as are many antibiotics. 

B14. Bowers, C. Y., Redding, T. W., and Schally, A. V., Effect of thyrotropin-releasing factor (TRF) of ovine, bovine, porcine and human origin on thyrotropin release in vitro and in vivo. Endocrinology 77, 609-616 (1965). 

Sinha, D., and Meites, J., Effects of thyroidectomy and thyroxine on hypothalamic concentration of thyrotropin releasing factor and pituitary content of thyrotropin in rats. Neuroendocrinology N. Y.) 1, 4-14 (1965). 

Spiess J, Rivier J, Vale W (1983) Characterization of rat hypothalamic growth hormone-releasing factor. Nature 303(5917) 532-5. PMID 6406907 Szabo M, Ruestow PC, Kramer DE (1985) Growth hormone response to thyrotropin-releasing hormone in the urethane-anesthetized rat effect of thyroid status. Endocrinology 117(1) 330—7... 

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