Effects of Long-Term Intraperitoneal Injection of Thyrotropin-Releasing Hormone (TRH) on Aging- and Obesity-Related Changes in Body Weight, Lipid Metabolism, and Thyroid Functions

Walter      Pierpaoli; Vladimir      A. Lesnikov

Abstract

Adult adipose mice, high fat diet-fed (HFD) mice, anterior hypothalamus-lesioned obese mice and genetically obese mice, were injected daily with thyrotropin releasing hormone (TRH). The treatment provoked a mobilization of triglycerides in the peripheral blood, a decrease of leptin and a loss of body weight. The weight loss did not depend on TSH-mediated stimulation of thyroid hormone secretion with consequent metabolic hyperthyroidism. The levels of blood cholesterol were not affected or even suppressed. Even at a very high dosage TRH did not affect the obesity of genetically obese mice. The ubiquitous tripeptide TRH may thus constitute a key element in the hormone-controlled regulation of body weight and fat stores in the adult and aging body.

Keywords: Thyrotropin releasing hormone, lipids, thyroid function, leptin, body weight, food intake, aging, triglycerides, hyperthyroidism, thymolytic-immunosuppressive effects, intraperitoneal (ip) route, anterior hypothalamic area (AHA), adiposity, halothane, narcosis, thyroxine (T4), triiodothyronine (T3), Free Fatty Acid (FFA), obesity, cholesterol levels, adipose, adipocytes, neuropeptide-Y (NPY), hypothalamic arcuate nucleus (ARC), paraventricular nuclei (PVN), homeostasis, phenotype, hypothalamic obesity, protein kinase, cylglycerol, Langerhans islets of the pancreas, amylase, pineal-hypothalamic-hypophysis axis, energy-adapting biochemical processes, thermoregulation, melatonin, hormonal cyclicity, homoeostasis, adipocyte-derived hormones