Radioimmunoassay For Growth Hormone Research Articles

Radioimmunoassay of growth hormone by enzyme partition.

ABSTRACT A reliable and sensitive radioimmunoassay for human growth hormone has been devised in which separation of antibody-bound and free radiohormone (HGH-125I) is accomplished by the principle of enzyme partition. Since the proteolytic enzyme, ficin, rapidly destroys most free HGH-125I, but does not degrade antibody-bound radiohormone, the 2 fractions can be readily distinguished by precipitation of the antibody-bound HGH-125I with trichloroacetic acid solution. With this elementary system, endogenous levels of growth hormone in serum can be conveniently measured in less than 24 hr with results that are comparable in precision and sensitivity with those of longer techniques that are currently in use. The successful application of enzyme partition to the assay of growth hormone, and previously to the measurement of insulin, suggests that the same principle could be employed to assay other hormones or substances that are bound by specific antibodies or nonspecific binding substitutes.

Radioimmunoassayable growth hormone in the rat pituitary gland: effects of age, sex and hormonal state.

A sensitive radioimmunoassay for rat growth hormone (GH) has been modified and used to study pituitary content of GH in the Sprague-Dawley rat under varying conditions. Growth hormone does not appear in the rat fetal pituitary until the 19th day of gestation. Day-old rats have low GH content and concentration but GH rapidly accumulates with age. By puberty the male rat has more pituitary GH than the female rat. This difference increases as the rats grow older. Estrogen treatment of the male rat lowers GH concentration and causes an increase in pituitary size. Testosterone treatment of the female rat leads to an elevation of GH content and concentration. Castration of male rats results in levels of GH that are indistinguishable from those of female rats. These studies indicate that factors of age, sex and gonadal hormones interact to affect pituitary content of growth hormone in the rat. (Endocrinology 81: 195,1967)

Hypoglycemia Induced Growth Hormone Secretion in Pituitary Diseases.

Excerpt The availability of a sensitive radio-immunoassay for growth hormone has made it possible to study pituitary function by directly measuring the capacity of the pituitary to release growth h...

Growth hormone: important role in muscular exercise in adults.

Measurement by radio-immunoassay of growth hormone in the plasma of adults showed consistently low concentrations in subjects in bed in the morning. Exercise caused marked increases except when the subjects ingested carbohydrate during the exercise.

EXTRACTION AND RADIOIMMUNOASSAY OF GROWTH HORMONE IN HUMAN SERUM.

A previously described radioimmunoprecipitation assay for human growth hormone has been further developed and the sensitivity has been increased. As little as 0.2 mμg growth hormone can now be detected. Growth hormone has been extracted free of serum interfering substances by an IRC-50 chromatographic procedure. With this method, no human growth hormone was detectable in animal serum and serum from some hypophysectomized subjects. The activity of human serum extracts could be removed by absorption of the serum with anti-human growth hormone serum before extraction. Recovery of human growth hormone added before extraction to human or animal serum averaged 88.3 %. The following growth hormone levels were obtained: normal children and adults, 2.0–7.8 mμg/ml; active acromegaly, 9.1–59.0 mμg/ml; hypopituitary and hypophysectomized subjects, 0–4.6 mμg/ml; nonpituitary dwarfism, 2.3–10 mμg/ml.