Participation of the CNS in the control of FFA mobilization during fasting in rabbits.
The presence of FFA-mobilizing areas in the rabbit central nervous system was investigated by injecting minute amounts of 2-deoxyglucose, glucose or insulin directly into the cerebrospinal fluid of conscious, unrestrained rabbits. Intracerebroventricular administration of minute amounts (10 mg) of deoxyglucose to fed rabbits produced a rapid increase in the concentration of plasma free fatty acids (FFA) and a slower increase in plasma glucose. Conversely, small amounts of insulin (50 microU) or glucose (2.5 mg) intraventricularly reduced the elevated plasma FFA of normal fasted rabbits without affecting plasma levels of glucose or insulin. The elevated levels of plasma FFA of diabetic rabbits were not affected by glucose administration, but clearly decreased after intraventricular insulin. Adrenodemedullation suppressed the hyperglycemia but not the plasma FFA increase induced by intraventricular 2-deoxyglucose. The data suggest that insulin-sensitive centers in the rabbit central nervous system participate in the control of FFA mobilization during fasting by modulating the lipolytic sympathetic tonus of adipose tissue, and that the activity of these centers is regulated by their rate of glucose utilization.
Department of Biochemistry, School of Medicine, Ribeirao Preto, Brazil.
M A
MA
Paschoalini
R H
RH
Migliorini
D000313:Adrenal Medulla / Q000502:physiology; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D003847:Deoxyglucose / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005215:Fasting / Q000097:blood / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D007276:Injections, Intraventricular; D007328:Insulin / Q000097:blood / Q000494:pharmacology; D008297:Male; D011817:Rabbits
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D003847:Deoxyglucose