Neonatal monosodium- l-glutamate treatment reduced lipolytic response of rat epididymal adipose tissue

Abstract

1. 1. The effect of neonatal monosodium- l-glutamate (MSG) treatment on lipolysis in rat epididymal adipose tissue was studied. A reduction in the basal lipolysis was observed in the MSG-treated rats. 2. 2. This was accompanied by a decreased lipolytic response to isoprenaline, adrenocorticotropic hormone, forskolin, isobutylmethylxanthine and dibutyryl-cAMP. 3. 3. The addition of adenosine deaminase, which inactivates endogenous adenosine in the medium, did not normalize the basal and the hormone stimulated lipolytic responses. 4. 4. The maximal lipolysis stimulated by adenosine deaminase or 8-( p-sulfophenyl)-theophylline (8-SPT), an adenosine antagonist, was significantly lower in the MSG-treated rats. 5. 5. Moreover, there was no change in the sensitivity of adenosine receptors to its antagonist as reflected by the similar potency of 8-SPT in eliciting the lipolytic response in both the control and MSG-treated rats. 6. 6. In conclusion, neonatal MSG treatment in rats induced a general reduction of lipolytic response in the epididymal adipocytes which cannot be explained by an enhancement of the adenosine inhibitory system.