Effects of epinephrine and theophylline on lipolytic response in hereditary diabetic mice

In non-obese but diabetic 15-week-old KK mice which showed fatty liver histopathologically, the content of liver lipids and the levels of blood glucose and plasma IRI were greater than those in the control ICR mice of the same age and were quite similar to those in GTG-obese mice. In 6-week-old KK mice which excreted no glycosuria and showed normal hepatic tissues, only plasma IRI level was slightly elevated as compared with that in the control mice. The cyclic 3',5'-AMP stimulators like epinephrine and theophylline exerted far less potent stimulatory effects on lipolytic activity in 6-week-old KK mice than in the control mice, as in diabetic 15-week-old KK mice and GTG-obese mice. Theophylline potentiated the lipolytic effect of epinephrine lineraly in KK mice, the tendency being different from that in the control mice, and only the submaximal rate was obtained. Furthermore, the inhibitory effect of theophylline on PDE from the epididymal adipose tissue was less potent in 6-week-old KK mice than in healthy ICR mice of the same age.