**4. Conclusions**

In this chapter, the main factors involved in the control of GH secretion were analyzed, including the explanation of why it is sexually dimorphic or its relationship with feeding or fasting.

Although GH has traditionally been considered a merely metabolic hormone with specific actions on the longitudinal growth of the organism until the end of puberty, a series of studies carried out in recent years show that this hormone is highly complex in terms of the number of actions so diverse that it exerts in the organism. This has led to the control of its secretion being very diverse, although it primarily depends on a control exerted negatively from the hypothalamus by somatostatin and an inducing effect of its release carried out by GHRH, although it also depends on the nutritional status, by a primarily gastric peptide such as ghrelin.

As is logical, given the multiplicity of GH actions, a series of hormonal, metabolic factors, or factors simply indicative of the functional state of a gland or tissue, or neurotransmitters, will condition the rate and type of GH secretion. Basically, these factors will act primarily on the secretion of somatostatin, activating it and, consequently, inhibiting the secretion of GHRH-stimulating peptide, or inhibiting SS so that GHRH can be released into the hypothalamic-pituitary portal circulation, and stimulate the synthesis and pituitary secretion of GH. The basic control of SS secretion depends on the adrenergic pathways that reach the neurons that produce it, being the α2-adrenergic inhibitory and the β-stimulants of its secretion, although some other factors, such as arginine or ghrelin, may act directly on SS neurons, while others, such as thyroid hormones, may act by regulating the number and responsiveness of GHRH receptors in the pituitary gland.
