title: The role of nitric oxide in the control of plasma glucose concentration in spontaneously hypertensive rats.
abstract: Glucose homeostasis was studied in the spontaneously hypertensive rat (SHR). The fasting plasma glucose levels were similar in the SHR and normotensive Wistar-Kyoto (WKY) rat (102.7+/-2.4 vs. 107.4+/-4.2 mg/dl, P > 0.01). One hour after glucose challenge, the plasma glucose level was slightly but insignificantly increased in both SHR and WKY rat (117+/-2.5 vs. 114.3+/-3.2 mg/dl, P > 0.01). After N(G)nitro-L-arginine methyl ester (L-NAME) 20 mg/kg per day was administered intraperitoneally (i.p.) for 4 days, the plasma glucose level was significantly increased in the rats (SHR 167.3+/-4.9; WKY rat 136.0+/-4.8 mg/dl); the increase was significantly more pronounced in the SHR. The fasting insulin levels were similar in the SHR and WKY rats (2.3+/-0.4 vs. 2.0+/-0.3 ng/ml, P > 0.01). One hour after glucose challenge, the insulin level was significantly increased in the WKY rat (4.8+/-0.7 ng/ml) but not in the SHR (2.2+/-0.4 ng/ml). With L-NAME treatment, plasma insulin increase was noted in the WKY rat but not SHR (4.6+/-0.6 vs. 2.6+/-0.4 ng/ml, n = 8, P < 0.01). One hour after insulin 1 IU/kg was injected intramuscularly (i.m.), the plasma glucose level was significantly decreased in both the SHR (from 115.0+/-6.5 to 48.6+/-3.6 mg/dl, n = 8) and WKY rat (from 108.3+/-3.8 to 52.6+/-4.2 mg/dl, n = 8). No significant difference was noted between the decrease of the two groups (P > 0.01). The present findings suggested that NO plays a role in the glucose homeostasis of rats. NO-synthase blockade resulted in an increase of plasma glucose level. The SHR maintains normal glucose level and tolerance in spite of a defective insulin release response. This is probably due the compensatory effect of a more prominent NO-dependent glucose homeostatic function.
authors.affiliation: Department of Urology, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Y C
authors.initials: YC
authors.lastname: Tong
authors.forename: C J
authors.initials: CJ
authors.lastname: Wang
authors.forename: J T
authors.initials: JT
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006706:Homeostasis; D006973:Hypertension / Q000097:blood*; D007328:Insulin / Q000097:blood; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D001786:Blood Glucose; D004791:Enzyme Inhibitors; D007328:Insulin; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester