Endocrine Development

Hypogonadism may be suspected if puberty is delayed. Pubertal delay may be caused by a normal physiological variant, by primary ovarian insufficiency (Turner syndrome), or reflect congenital hypogonadotropic hypogonadism (HH; genetic) or acquired HH (brain lesions). Any underlying chronic disease like inflammatory bowel disease, celiac disease, malnutrition (anorexia or orthorexia), or excessive physical activity may also result in functional HH. Thus, girls with delayed puberty should be evaluated for an underlying pathology before any treatment, including oral contraception, is initiated...

Passage from childhood to adult life involves biological changes culminating in full reproductive capacity as well as psychosocial development. For patients with congenital hypogonadotropic hypogonadism (CHH), this can be an emotionally challenging time as their pubertal failure results in striking physical differences from their peers. CHH is difficult to differentiate from common disorders of puberty such as constitutional delay of growth and puberty. As such, delays in diagnosis are frequent, and it is a common source of stress and frustration for these adolescents...

Hypothalamic obesity (HO) is a rare and serious disease of various origins: tumor, traumatism, radiotherapy, vascular, genetic, or even psychotropic drug use. HO usually begins in childhood with eating disorders and progresses with an aggregate of severe comorbidities. Transition from pediatric to adult health care is a critical period to assure weight stability and a good management of comorbidities. In case of loss to follow-up, there is an increased risk of major weight gain and long-term complications with severe obesity...

Recent advances in fertility preservation (FP) techniques have led to a wide spread of indications. FP should now be discussed not only for young girls having to receive gonadotoxic treatments for cancer, but also for those with genetic or endocrine disorders, as well as benign ovarian diseases at risk of premature ovarian insufficiency. For premenarchal girls, ovarian tissue cryopreservation is still the only available technique. Oocyte cryopreservation after ovarian stimulation could be offered to postmenarchal girls...

Girls with Turner syndrome (TS) require special consideration during transition from childhood to adult care. During the transition years, treatment for short stature will be completed and sexual development induced in parallel with the peer group. The timing of sexual development may have later repercussions with respect to psychosocial development and partnership status. Late presentation of TS, which is so common, can result in additional difficulties with the transition process.

Adolescence and young adulthood are times of multiple developmental changes, including physiological, social, emotional, cognitive, and behavioral transformations. The adolescent or young adult living with type 1 or type 2 diabetes must navigate the vicissitudes of these developmental stages while managing the rigors and self-care demands of these conditions. Diabetes in children is managed by adults, mainly by parents. As the child matures, diabetes management tasks transition from parents to the developing teen...

Transition has been defined as "the purposeful, planned movement of adolescents and young adults with chronic physical and medical conditions from child-centered to adult-oriented health care systems." We will here describe the challenges of such a process: challenges coming from the pediatrician, from the adolescent, linked to the disease itself, and those from the parents. We will outline how to overcome those fears and challenges to provide a successful transition process. A key factor to underline that process is that a relationship based on confidence should be established between the pediatrician and the physician for adults, in order for that relationship, based on trust, to be the basis for the transfer of the adolescent from the pediatric system of care to the adult one...

Deficiency of the 21-hydroxylase enzyme is the most common form of congenital adrenal hyperplasia (CAH), accounting for more than 95% of the cases. With the advent of newborn screening and hormone replacement therapy, most children with CAH survive into adulthood. Adolescents and adults with CAH experience a number of complications, including short stature, obesity, infertility, impaired bone mineral density, and reduced quality of life. Transition from pediatric to adult care and management of long-term complications are challenging for both patients and practitioners...

Spermatozoa have occasionally been identified in ejaculate of adult Klinefelter syndrome (KS) patients but very exceptionally in KS adolescents. Spermatozoa can also be retrieved in testicular tissue of KS adolescents. The testis may also harbor spermatogonia and noncompletely differentiated germ cells. Neither clinical features nor hormonal parameters could predict germ cell recovery in KS adults or adolescents. No predictive factors can actually demonstrate that early diagnosis of KS would allow increasing the chance of sperm retrieval even if it has been suggested that semen quality may decline with age in KS patients...

Growth hormone (GH) is essential not only for normal growth during childhood, but also for the acquisition of bone mass and muscle strength in both sexes. This process is completed after the achievement of adult height in the phase of transition from adolescence to adulthood. Adolescents with childhood onset GH deficiency (GHD) show reduction of bone mineral density, decrease in lean body mass, increase in fat mass, and deterioration of the lipid profile. For this reason, continuation of GH replacement therapy in the transition age is recommended in all patients with a confirmed diagnosis of GHD...

Considering the patient's transition from child to adolescent to adult and its psychological aspects in endocrinology and diabetology, it is necessary to recall the child's psycho-affective development when he enters adolescence. Indeed, adolescence appears paradigmatic of the "child-adult" transition; it is a specific and decisive psychic process which allows the child to become an adult, that is to say autonomous and subject to his desire. In our paper, we study the resonance of a chronic disease in young people; type 1 diabetes is chosen...

Gut bacteria exert a variety of metabolic functions unavailable to the host and are increasingly seen as a virtual organ located inside our gastrointestinal tract. Scattered in our intestinal epithelium, enteroendocrine cells (EECs) regulate several aspects of the host's physiology and translate signals coming from the gut microbiota through their hormonal secretions. In this chapter, we will assess the interplay between the gut microbiota and EEC and its consequences for the physiology of the host. We will first describe alterations of different populations of EEC in germ-free animals...

The physiological studies by British physiologists William Maddock Bayliss and Ernest Henry Starling, at the beginning of the last century, demonstrated the existence of specific messenger molecules (hormones) circulating in the blood that regulate the organ function and physiological mechanisms. These findings led to the concept of endocrinology. The first 2 hormones were secretin, discovered in 1902, and gastrin, discovered in 1905. Both hormones that have been described are produced in the gut. This chapter summarizes the history around the discovery of these 2 hormones, which is perceived as the birth of endocrinology...

Obesity and its comorbidities such as type 2 diabetes constitute major worldwide health threats, and the identification of an effective medical intervention has emerged as a global priority. The limited effectiveness of historical, anti-obesity treatments is commonly attributed to the complexity of the disease and the redundancy of metabolic regulatory mechanisms that sustain body weight. At the forefront of obesity research is the development of combinational drug therapies that simultaneously target multiple regulatory pathways, which promote dysfunctional metabolism...

The long-lasting weight-reducing effect of bariatric surgical procedures cannot simply be explained by the malabsorption of nutrients and the subsequent energy deficit due to this malabsorption. Clinical studies have shown that the reorganization of the anatomy of the gut and the subsequent alterations of gastrointestinal physiology have a large impact on the secretion and function of gastrointestinal hormones, which regulate hunger and satiety. These changes have been named the BRAVE effect: <under>b</under>ile flow alteration, <under>r</under>eduction of gastric size, <under>a</under>natomical gut rearrangement and altered flow of nutrients, <under>v</under>agal manipulation, and <under>e</under>nteric gut modulation...

Despite greater health education, obesity remains one of the greatest health challenges currently facing the world. The prevalence of obesity among children and adolescents and the rising rates of prediabetes and diabetes are of particular concern. A deep understanding of regulatory pathways and development of new anti-obesity drugs with increased efficacy and safety are of utmost necessity. The 2 major biological players in the regulation of food intake are the gut and the brain as peptides released from the gut in response to meals convey information about the energy needs to brain centers of energy homeostasis...

Humans have an innate liking for sweetness, which may have an evolutionary basis. Sweetness typically signals the presence of calories and nutrients and thus, universal liking for sweet taste once served to support survival. In the modern food supply, however, sweetness is often delivered via added sugars and sweeteners devoid of other beneficial nutrients. Nonnutritive sweeteners (NNS) provide sweetness with no or few calories, and therefore may offer a potential strategy to maintain food and beverage palatability, while reducing the caloric content...

Ghrelin is a pleiotropic hormone, whose effect on growth hormone secretion, through the growth hormone secretagogue (GHS) receptor, is one of its many actions. Relationships between GHS receptor gene variants and human height, both in healthy individuals and in patients with growth disorders have been identified. These include constitutional delay in growth and puberty, idiopathic short stature, and isolated growth hormone deficiency. In this review, we provide an overview of the role of ghrelin in growth.

Enteroendocrine cells (EEC) have been studied extensively for their ability to regulate gastrointestinal motility and insulin release by secretion of peptide hormones. In particular, the L cell-derived incretin glucagon-like peptide 1 has gained enormous attention due to its insulinotropic action and relevance in the treatment of type 2 diabetes. Yet, accumulating data indicates a critical role for EEC and incretins in metabolic adaptation and in orchestrating immune responses beyond blood glucose control. EEC actively sense the lamina propria and luminal environment including the microbiota via receptors and transporters, subsequently mediating signals by secreting hormones and cytokines...

Incretins are hormones secreted into the blood stream from the gut mucosa in response to nutrient intake. They have been characterized based on their capacity to lower blood glucose levels. The more potent reduction of blood glucose coupled to a more intensive stimulation of insulin secretion, in response to oral glucose uptake, as compared to intravenous glucose infusion has further been termed the "incretin effect." As a prototype incretin hormone, the biology of glucagon-like peptide 1 (GLP-1) has been intensively studied...