Evaluation of Some Puberty-related Hormones Among Children and Adolescents With Chronic Kidney Diseases

Puberty is the process of transition from childhood into adolescence, signaling the readiness of the human body for reproduction. The Hypothalamic-Pituitary Gonadotropin axis plays the primary role in initiating the puberty, where the hypothalamus secrets gonadotropin releasing hormone (GnRH) in a pulsatile manner, which in turn stimulates the release of luteinizing hormone (LH), and follicle stimulating hormone (FSH) from the anterior lobe of the pituitary gland, and in a final step these hormones stimulate the gonads to release their sex hormones (Testosterone and Estradiol) . Chronic illnesses can affect this physiological process resulting in delayed puberty . Delayed puberty is defined as the lack of pubertal signs until the age of 13 years in girls, and the age of 14 years in boys. Delayed puberty is classified into two categories according to their cause; central gonadotropin deficiency (hypogonadotropic hypogonadism) and this type comprises delayed puberty due to chronic illness, while the second category of delayed puberty is due to gonadal disorders (hypergonadotropic hypogonadism). Delayed puberty is common among pediatric patients with chronic kidney disease (CKD) - where glomerular filtration rate (GFR) is less than 60 ml/min per 1.73 m2. Previous studies suggested that, the cyclic pattern of GnRH release is lost in patients with CKD resulting in impairment of gonadotropins secretion from the anterior pituitary gland. Multiple hormonal factors had been proposed to be responsible for the pubertal delay in patients with CKD, the most prominent of which is the increasing levels of prolactin, LH and GnRH (4). Prolactin normally inhibits the release of GnRH from hypothalamus thus inhibiting the initiation of puberty and it was found to increase in patients with CKD secondary to increased production, slightly decreased clearance and decreased responsiveness to the hypothalamic inhibition of prolactin secretion. Furthermore, recent studies reported that the