True. Leptin is a peptide hormone secreted primarily by white adipose tissue (fat cells). Its level in the blood is proportional to the amount of body fat. Leptin acts as a long-term signal of energy stores, informing the brain about the body's fat reserves. It crosses the blood-brain barrier and binds to receptors in the hypothalamus, specifically in the arcuate nucleus. There, it inhibits neurons that stimulate hunger (e.g., those producing neuropeptide Y) and activates neurons that promote satiety. This leads to reduced food intake and increased energy expenditure. In conditions of leptin deficiency (rare) or leptin resistance (common in obesity), this satiety signal is impaired, contributing to overeating and weight gain. Leptin's discovery established fat tissue as an active endocrine organ.

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Zambia

• ivwananji siwale – 29 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies