Causes of high and low growth hormone

Increased serum growth hormone concentration is observed in acromegaly (in 80% of patients - more than 10 ng / ml) and gigantism, which are more often associated with growth hormone - producing pituitary adenoma. The main method of laboratory diagnosis of gigantism and acromegaly is determination of serum growth hormone concentration on an empty stomach (the average value of 3-fold determination for 2-3 days with breaks of 1-2 days is calculated). Usually, the concentration of growth hormone in the blood of patients is 2-100 times higher than normal (sometimes reaching 400 ng / ml). With close to normal values of growth hormone content in the blood on an empty stomach (in 30-53% of patients), to confirm the diagnosis and establish the phase of the disease (active or inactive), it is necessary to study the daily rhythm of growth hormone secretion (in the active phase it exceeds normal values by 2-100 times or more), as well as conduct a number of physiological and pharmacological tests. To clarify the diagnosis, the somatotropic hormone content in the serum is studied at intervals of 1-2 months. In acromegaly, the determination of somatotropic hormone in the blood serum in the dynamics of the disease is necessary to assess the effectiveness of conservative therapy and the radicality of surgical treatment. Drug therapy for acromegaly is considered adequate if the concentration of somatotropic hormone does not exceed 10 ng / ml. Effective gamma or proton therapy leads to normalization of the concentration of somatotropic hormone in the blood. The result of gamma therapy is assessed no earlier than 2 months, and proton therapy - 4 months after the end of treatment. Radical surgery also contributes to the normalization of the somatotropic hormone content within a few days. The completeness of somatotropinoma removal is assessed using a glucose tolerance test with a study of the somatotropic hormone content in the blood serum on an empty stomach, as well as 1 and 2 hours after glucose intake. A decrease in the concentration of somatotropic hormone during the test to 2.5 ng/ml and below indicates the radical nature of the adenomectomy performed.

Reduced secretion of somatotropic hormone during the growth period leads to dwarfism. In pituitary dwarfism, secretion of somatotropic hormone is reduced, and the daily rhythm of secretion is not observed. If the content of somatotropic hormone in a sample taken on an empty stomach exceeds 10 ng/ml, its deficiency can be excluded. At lower values, additional studies are necessary. Various diagnostic tests are carried out, since the lower limit of normal concentration of somatotropic hormone in the blood is close to the sensitivity limit of existing laboratory methods for its determination.

Quite recently, somatotropic hormone deficiency in adults has been identified as an independent nosological entity. Clinically, growth hormone deficiency in adults is manifested by an increase in body weight due to an increase in adipose tissue, a decrease in the amount of fluid in the body (mainly due to extracellular fluid) and bone mineral density. In the blood, an increase in the concentration of VLDL, LDL, TG and a decrease in HDL are detected (normalization of their level is an important criterion for assessing the effectiveness of replacement therapy in such patients). The concentration of IGF-I in the blood serum is not used as a criterion for growth hormone deficiency in adults due to the significant variability of reference values.

The concentration of growth hormone in the blood may decrease in children with primary hypothyroidism. Successful treatment of hypothyroidism leads to its normalization.