IGF-1: What it is
Insulin-like growth factor (IGF-1 insuline-like growth factor), also known as somatomedin, is a protein-like hormone with a molecular structure similar to that of insulin. IGF-1 plays a very important role in the child's growth processes and maintains its anabolic effects even in adulthood.
Once produced, IGF-1 is released into the circulation, where it binds to special proteins called IGF-BP (IGF-binding proteins or transport proteins of IGF1). These six proteins increase the plasma half-life (from 10 minutes to 3-4 hours) thus prolonging the stay time of the hormone in the circulation.
Functions
IGF-1 has similar insulin activity and promotes cell proliferation and differentiation, especially at cartilage and muscle level (promotes activation of satellite cells). The biological functions of somotomedin take place both with an autocrine and a parocrine / endocrine mechanism depending on whether the target tissues are the same ones that produce it (autocrine) or others (parocrine if it reaches these tissues with the extracellular fluid, endocrine if the transport fluid is the blood).
Local production of IGF-1 is very important because many effects of this hormone fall directly on neighboring cells (paracrine mechanism). At the muscular level there exists, for example, an isoform of IGF-1 called MGF (mechanical growth factor).
Like all hormones of a protein nature, IGF-1 also needs specific cellular receptors to perform its action. These receptors are concentrated mainly in some tissues such as muscle, bone, cartilage, cutaneous, nervous and renal. Their activity is very similar to that of the insulin receptors and not surprisingly, a small amount of somatomedin is picked up by the insulin receptors. Along with IGF-1, two other proteins have been discovered, called IGF-2 and IGF-3 with activity similar to IGF-1.
Interactions with growth hormone
Many actions of GH are mediated by IGF-1 and vice versa. Unlike somatotropin (GH), the somatomedin plasma levels are relatively constant during the day and do not undergo the typical fluctuations of other anabolic hormones, secreted at circadian rhythm (GH, testosterone).
IGF-1 concentrations gradually increase in childhood and puberty, and then fall into adulthood.
In obese subjects, although GH levels are reduced, IGF1 levels are normal. IGF-1 deficiency and deficiency or reduced functionality of its receptors are found in growth retardation (dwarfism), in cases of liver failure, in hypothyroidism and in diabetics.
Physiologically the lowest values are found in childhood and in old age. However this decline related to aging can be prevented by an adequate level of physical activity.
IGF-1 is therefore a powerful cellular growth factor, a hormone with strong anabolic properties whose mechanisms of action have not yet been completely clarified. At bone level, for example, it stimulates the activity of chondrocytes, the cells responsible for the synthesis of new cartilage and promotes the activity of osteoblasts, increasing bone trophism.
Many of these effects depend on the interaction with GH. This association increases nitrogen retention (positive nitrogen balance), stimulates the activity of satellite cells, promotes the elimination of excess adipose tissue and improves the synthesis of DNA, RNA, collagen and hyaluronic acid, thanks to the action stimulus of fibroblasts.
Currently the research is focusing on the use of this hormone in the treatment of diseases such as diabetes, osteoporosis, muscular dystrophy and dwarfism. These diseases are in fact related to reduced plasma levels of IGF-1.
Increase GF-1 naturally
Like all other anabolic hormones, the effects of which have been widely demonstrated (DHEA, testosterone and GH), even IGF-1 has attracted the attention of many athletes. However, the reduced number of studies on the efficacy and possible side effects of an exogenous administration and the relative dependence on a hormone much more studied and popular as GH, have partly dampened the enthusiasm for this peptide.
This class of hormones is in fact attributed an impressive series of beneficial activities, sometimes almost miraculous, which find fertile ground in the common desire to reach or maintain beauty, physical prowess, strength and youth.
Pending studies that revive the properties of this hormone and the birth of the usual supplements with a presumed stimulating action, we see some general advice to increase the synthesis of IGF-1 in a natural way.
Being an anabolic hormone, its maximum stimulation occurs during high intensity exercises with strong lactic acid production. Bodybuilding therefore seems the most suitable activity to increase the secretion and beneficial effects of IGF-1. Specifically, the maximum stimulus is obtained with high intensity workouts that do not exceed 45 minutes. However, this type of training can only be practiced by healthy and experienced athletes, while it is not recommended for diabetics, hypertensives, heart patients and those suffering from serious joint problems. In these cases, aerobic-type activities such as running or cycling are more appropriate, although, although they have a lower effectiveness, they undoubtedly contribute to slowing down the aging process.
A diet rich in proteins contributes to enhancing the effects of IGF-1 and in some ways to stimulate its secretion, provided that you do not overdo it with doses. In fact, remember that even proteins, if taken in excess, unnecessarily fatigue the entire body. The waste produced, increasing the accumulation of toxins, favors the deposition of fat and the decrease of muscle mass, decreasing the efficiency of the organism. The diet must therefore also be rich in water, fiber and vitamins. The advice continues at this point with routine recommendations such as abstinence from alcohol, drugs and smoking, observance of the right night rest period and stress reduction.
IGF-1, Doping and Tumors
High blood levels of this protein seem to be related to an increased risk of cancer. Indeed, IGF-1 plays an important role, not only in muscle growth, but also in the development of cancer cells.
As we have seen, diet and exercise significantly influence IGF-1 levels. These values can however undergo a much more rapid and unnatural increase following the use of doping substances, with the consequent risk of developing certain types of tumors such as prostate cancer.
