The effect of glucose and free fatty acids on growth hormone (GH)-releasing factor-mediated GH secretion in rats.
We have examined the effect of glucose and FFA on GH-releasing factor (GHRF)-mediated GH secretion in rats under pentobarbital anesthesia. Hyperglycemia did not affect GH secretion induced by administration of 20, 100, and 200 ng GHRF/100 g body weight. In contrast, GH response to 50 ng GHRF/100 g body weight in lipid heparin-treated rats, which showed high plasma FFA levels, was significantly suppressed compared with the control group (plasma peak GH: control, 1526 +/- 263 ng/ml; lipid-heparin group, 377 +/- 69 ng/ml P less than 0.05, mean +/- SEM). This suppressive effect of FFA on GH secretion was abolished by pretreatment with antisomatostatin serum (ASS) (GH level at 4 min after GHRF administration: ASS-saline group, 1606 +/- 210 ng/ml; ASS-lipid-heparin group, 1531 +/- 174 ng/ml; mean +/- SEM). These results suggest that hyperglycemia does not change the GH response to GHRF and that elevation of plasma FFA suppresses GHRF-induced GH secretion by the stimulation of somatostatin secretion in rats.
Imaki
T
T
Shibasaki
T
T
Masuda
A
A
Hotta
M
M
Yamauchi
N
N
Demura
H
H
Shizume
K
K
Wakabayashi
I
I
Ling
N
N
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology*; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D007106:Immune Sera / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000276:immunology
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007106:Immune Sera; D013004:Somatostatin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D005947:Glucose