Growth hormone in the blood serum
Diurnal rhythm of secretion of STH with peaks of its concentration above 6 ng / ml 1-3 hours after falling asleep irrespective of time of day is formed to 3 months after birth. The average daily concentration of STH increases during puberty, decreases after 60 years;at the same time, diurnal rhythms disappear. Sexual differences in secretion of STH were not revealed. The reference concentrations of serum HGS in the blood serum are presented in the table.
Table Reference values for serum concentration of serum
Table Reference values for serum concentration of serum
Increase in serum concentration of serum is observed in acromegaly( in 80% of patients - more than 10 ng /ml) and gigantism, which are more often associated with the pituitary adenoma of the pituitary gland. The main method of laboratory diagnostics of gigantism and acromegaly is the determination of the concentration of STH in the fasting serum( the mean value of the 3-fold determination is calculated over 2-3 days with 1-2-day intervals).Usually the concentration of STH in the blood in patients is 2-100 times higher than normal( sometimes reaches 400 ng / ml).At close to normal indices of fasting blood glucose in the blood( in 30-53% of patients) to confirm the diagnosis and establish the phase of the disease( active or inactive), it is necessary to investigate the daily rhythm of secretion of STH( in the active phase exceeds the normal values of 2-100 times and more), and carry out a number of
physiological and pharmacological tests. To clarify the diagnosis, the content of serum in the serum is examined at intervals of 1-2 months. In acromegaly, the determination of STH in serum in the dynamics of the disease is necessary to assess the effectiveness of conservative therapy and the radical nature of surgical treatment. Drug therapy for acromegaly is considered adequate if the concentration of STH does not exceed 10 ng / ml. Effective gamma or proton therapy leads to a normalization of the concentration of STH in the blood. The result of gamma-therapy is estimated not earlier than 2 months, and proton therapy - after 4 months after the end of treatment. A radically conducted operation also contributes to the normalization of the STH content within a few days. Completeness of removal of somatotropinoma is assessed using glucose tolerance test with the study of the content of hyperglycemia in blood serum on an empty stomach, and also 1 and 2 hours after glucose intake. Reduction of the concentration of STH during the test to 2.5 ng / ml and lower indicates a radical adenomectomy.
The decreased release of STH during the growth period leads to dwarfism. In hypophysical nanism, the secretion of STH is reduced, the daily rhythm of secretion is not traced. If the amount taken in an empty stomach is higher than 10 ng / ml, its insufficiency can be excluded. At lower values, more research is needed. Various diagnostic tests are performed, since the lower limit of normal concentration of blood glucose in the blood is close to the sensitivity limit of existing laboratory methods for its determination.
More recently, the failure of STH in adults has been isolated into an independent nosological form. Clinically, the failure of STH in adults is manifested by an increase in body weight due to the growth of adipose tissue, a decrease in the amount of fluid in the body( mainly due to extracellular) and bone mineral density. In the blood, an increase in the concentration of VLDLP, LDL, TG and a decrease in HDL is revealed( normalization of their level is an important criterion for evaluating the effectiveness of substitution treatment in such patients).The concentration of IAPF I in the blood serum as a criterion for the failure of STH in adults is not used because of the considerable variability in the reference values.
Concentration of STH in the blood can decrease in children with primary hypothyroidism. Successful treatment of hypothyroidism leads to its normalization. Diseases and conditions in which the content of STH in the blood can vary are presented in the table.