Leptin

Leptin (from Greek λεπτός leptos, "thin") is a hormone predominantly made by adipocytes and enterocytes in the small intestine that helps to regulate energy balance by inhibiting hunger, which in turn diminishes fat storage in adipocytes

Leptin regulates food intake and energy expenditure
López-Moreno et al. 2020 Nutrients 12: 1921

Obese individuals have an increased level of an adipokine called leptin which has an explicit role that regulates the constitution of the gut microbiota via the modulation of the secretion of antimicrobial molecules by the Paneth cells in the intestine, namely, a vicious circle between the microbiota and the adipose tissue, that promotes further worsening of the degree of obesity
Musso et al. 2011 Annu Rev Med 62: 361-380

When leptin is administered directly intracerebroventricularly to avoid peripheral resistance, a rapid reduction in food intake and body weight is observed in obese animals
Hwa et al. 1996 Horm Metab Res 28: 659-663
Van Heek et al. 1997 J Clin Invest 99: 385-390
Ramsey et al. 1998 J Clin Endocrinol Metab 83: 3230-3235
El-Haschimi et al. 2000 J Clin Invest 105: 1827-1832

see also:
Adipocytokine / Adipokine
Appetite regulation & Hormones / Hormone System