Insulin-like growth factor I in the blood

Insulin-like growth factor I in serum

The main factor determining the concentration of IGFR I in the blood serum is age. The concentration of IGFR I in the blood increases from very low values (20-60 ng / ml) at birth and reaches peak values (600-1100 ng / ml) during puberty. Already in the second decade of a person's life, the level of IGFR I begins to decline rapidly, reaching average values (350 ng / ml) at the age of 20 years, and then decreases more slowly with each decade. At 60 years, the concentration of IGFR I in the blood is not more than 50% of that at the age of 20 years. Daily fluctuations in the concentration of IGFR I in the blood were not detected.

Conditions affecting the concentration of blood glucose in the blood

Increase in concentration	Reduction in concentration
Acromegaly and Gigantism Starvation, stress, alcoholism Chronic kidney failure Post-traumatic and postoperative conditions Porphyria, hyperglycemia Ectopic production by tumors of the stomach, lungs Hyperpituitarism Physical activity ACTH, vasopressin, estrogens, noradrenaline, dopamine, serotonin, clonidine, propranolol, bromocriptine, arginine, insulin, vitamin PP, amphetamine	Pituitary dwarfism Hypercortisy Obesity Chemotherapy, radiotherapy Operative interventions Syndrome Itenko-Cushing Factors causing hyperglycemia Hypopituitarism Anencephaly in the fetus Progesterone, glucocorticosteroids, phenothiazines, somatostatin, glucose

Reference values of concentration of IGFR I in blood serum

Age, years	Floor	IGFR I, ng / ml
1-3	Male	31-160
	Women's	11-206
3-7	Male	16-288
	Women's	70-316
7-11	Male	136-385
	Women's	123-396
11-12	Male	136-440
	Women's	191-462
13-14	Male	165-616
	Women's	286-660
15-18	Male	134-836
	Women's	152-660
18-25	Male	202-433
	Women's	231-550
26-85	Male	135-449
	Women's	135-449

The concentration of IGFR I in the blood depends on the growth hormone, and also on T ₄. Low levels of IGF I detected in patients with severe impairment T ₄. Carrying out substitution therapy with preparations of levothyroxine sodium leads to a normalization of the concentration of IGFR I in the blood serum.

Another factor determining the concentration of IGFR I in the blood is the nutritional status. Adequate protein-energy supply of the body is the most important condition for maintaining the normal concentration of IGFR I in the blood both in children and adults. In children with severe energy and protein deficiency, the concentration of IGFR I in the blood is reduced, but it is easily amenable to correction during normalization of nutrition. Other catabolic disorders, such as hepatic insufficiency, inflammatory bowel disease, or renal failure, are also associated with a low content of IGFR I in the blood.

In clinical practice, the study of IGFR I is important for assessing the somatotropic function of the pituitary gland.

With acromegaly, the concentration of IGFR I in the blood is constantly increased and therefore is considered a more reliable criterion for acromegaly than the content of growth hormone. The average concentration of IAPF I in the blood serum in patients with acromegaly is approximately 7 times higher than the normal age. The sensitivity and specificity of the IGFR I study for the diagnosis of acromegaly in patients over 20 years old exceeds 97%. The degree of increase in the concentration of IGFR I in the serum correlates with the activity of the disease and the growth of soft tissues. The determination of the serum level of IGFR I is used to monitor the effectiveness of treatment, as it correlates well with the residual secretion of growth hormone.

The following laboratory indicators are considered criteria for the cure of acromegaly:

• the concentration of growth hormone in the blood on an empty stomach is less than 5 ng / ml;
• the concentration of growth hormone in the blood is below 2 ng / ml when carrying out PTTG;
• concentration of IGFR I in the blood within the limits of normal values.

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12]