Adipose tissue of rats pretreated with 5-carboxy-3-methylpyrazole (5C3MP) or nicotinic acid released less glycerol and FFA (basal lipolysis) in their incubation medium. However, they were more sensitive to the lipolytic action of norepinephrine or theophylline. The maximum release of FFA and glycerol due to norepinephrine addition was increased in adipose tissue from 5C3MP pretreated rats. Moreover, the sensitivity to cyclic 3′5′ AMP (dibutyryl ester) was not significantly increased. The hypersensitivity to lipolytic agents already appeared at times when plasma FFA were lowered, but was present also during the rebound phase. Adrenalectomy did not prevent the inhibition of lipolytic activity exerted by these compounds, but almost completely inhibited the hypersensitivity of adipose tissue of treated rats to lipolytic agents. The possibility that these changes in the responsiveness of adipose tissue were correlated with the increased level of plasma corticosterone observed after the administration of 5C3MP or nicotinic acid are taken into consideration. A possible role of the hypersensitivity in the onset of rebound effect is discussed.
|Number of pages||8|
|Publication status||Published - Sep 1969|
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