Guanethidine treatment does not block the ability of central leptin administration to decrease blood glucose concentrations in streptozotocin-induced diabetic rats.
Leptin, administered either into the ventricles of the brain or systemically, has been shown to normalize blood glucose concentrations in streptozotocin (STZ)-induced diabetic rats. We hypothesized that an intact sympathetic nervous system is necessary for centrally administered leptin to normalize or attenuate high blood glucose concentrations in STZ-induced diabetic rats. Young male Wistar rats (approximately 50 g) were treated every other day with either s.c. guanethidine (100 mg/kg) or vehicle for 2 weeks. Rats were then implanted with an intracerebroventricular cannula directed to the lateral ventricle and made diabetic with an i.v. injection of STZ (50 mg/kg). Half of the animals in each group were given daily injections of leptin (10 microl), while the remaining animals received vehicle injections. Blood glucose concentrations were measured daily and tissue norepinephrine content was determined by high performance liquid chromatography at the end of the study. Guanethidine pretreatment did not block the ability of centrally administered leptin to decrease blood glucose concentrations in diabetic rats. This suggests that the sympathetic nervous system does not mediate the leptin-induced attenuation of high blood glucose concentrations observed in diabetic rats.
Wang
Jinpin
J
Department of Nutrition and Food Science, Auburn University, Auburn, Alabama 36849, USA.
Wernette
Catherine M
CM
Judd
Robert L
RL
Huggins
Kevin W
KW
White
B Douglas
BD
D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism; D052436:Adipose Tissue, White / Q000187:drug effects / Q000378:metabolism; D018663:Adrenergic Agents / Q000494:pharmacology*; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D006145:Guanethidine / Q000008:administration & dosage / Q000494:pharmacology*; D020738:Leptin / Q000008:administration & dosage / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000187:drug effects / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology
D018663:Adrenergic Agents; D001786:Blood Glucose; D020738:Leptin; D009638:Norepinephrine; D006145:Guanethidine