Effect of lipolytic agents on healthy and pathological human adipose tissue

Abstract

Summary Lipolytic process in lipomata offers a new approach to elucidate the control mechanism of hormonal action in human adipose tissue. The aim of the present work has been to establish, first, if lipolytic drugs affected differently the normal from the pathological adipose tissue. Second, it was of interest if the pathology included any change in the hormonal control of lipolysis which could result in altered lipomobilization. Three types of lipomatosis were examined and compared with normal subcutaneous adipose tissue (NT) from the same patients. Pathological tissue was obtained from patients with multiple symmetric lipomatosis (MSL), Barraquer Simmons (BS) and simple, or nodular, lipomatosis (SL). The lipolytic process was studied a) by determination of the tissue FFA content, and of FFA and glycerol release into the incubation medium either under basal conditions or after addition of adipokinetic agents such as catecholamines, theophylline or dibutyryl cyclic AMP (db-cAMP). b) Basal intraccllular ATP content was quantified both in normal and pathological tissues. Lipolytic rate was closely similar between normal tissue and simple lipomatosis. On the contrary, the response to lipomobilizing agents was distinctly altered in both MSL and BS lipomatosis. In MSL lipomatous tissue only theophylline or db-cAMP stimulated the lipolysis markedly, whereas catecholamine induced lipolysis was absent. In this tissue however cholera toxin induced an high and dose-dependent lipolytic effect. In BS lipoma neither basal nor stimulated lipolysis was found. These results suggest a fine modulation in man by biochemical events within the lipolytic process and point to distinct control modalities in lipomobilization.