GHRL and obesity due to melanocortin 4 receptor deficiency: Hypothalamic development during the perinatal period can be easily affected by neuroendocrine‐related hormones (e.g., leptin, insulin, and ghrelin) and nutritional changes (e.g., maternal obesity and HFD).[25, 27, 31, 33, 34, 35, 37, 83] For example, the adipocyte‐derived hormone leptin has been found to play a neurotrophic role in the development of the hypothalamus during the neonatal period,[35] while neonatal ghrelin (a stomach‐derived hormone) exposure blocked the neurotrophic effect of leptin.