High Sensitivity Human Growth Hormone (H-hGH) ELISA Kit. For the quantitative determination of human growth hormone (hGH) concentrations in serum. This high-sensitivity Human Growth Hormone ELISA Kit is to be used for the in vitro quantitative determination of human growth hormone (hGH) concentrations in serum. This kit is intended FOR LABORATORY RESEARCH USE ONLY, and is not to be used in diagnostic or therapeutic procedures.
Human growth hormone (GH) is a 22kD monomeric protein produced and stored in somatotrophs in the anterior pituitary gland. GH is released from the pituitary into the bloodstream in a pulsatile manner under the regulatory control of hypothalamic somatostatin (SS) and GH-releasing factor (GHRF) [1]. The timing and frequency of GH release appears to be regulated by somatostatin, while the amplitude of GH release is determined by GHRF. A minor fraction (~10%) of GH in circulation exists in a smaller 20kD form [2]. GH has profound effects on tissue growth and metabolism, which is thought to be mediated through GH-dependent production of IGF-I and IGF-II, and their associated binding proteins. GH apparently stimulates IGF production after binding to specific cell surface receptors in the liver and, possibly, other tissues. Almost 50% of GH in circulation is bound to a high affinity GH binding protein (GHBP), which represents the extracellular domain of the GH receptor. Deficient GH secretion can occur in a number of clinical conditions [3]. However, evaluation of GH deficiency is complicated by the episodic nature of GH secretion and low circulating levels. A variety of physiologic and pharmacologic stimuli have been used to stimulate pituitary GH release during testing and failure to achieve a normal serum GH level in response to at least 2 GH stimulation or provocative tests is considered to be a diagnostic of GH deficiency [4]. The definition of a normal serum GH response is controversial, although published values generally range from 5 to 10ng/ml. GH excess (or acromegaly) can be caused either by direct GH hypersecretion or GH excess secondary to GHRF hypersecretion.
