Influence of norepinephrine administration upon pituitary hormone secretion in normal men.
This study has investigated the effects of 6.2, 12.5, 25, 50 and 100 ng/kg/min/60 min of NE infused to normal men. Blood samples were obtained every 10 min, before, during and after drug administration for 3 consecutive h. Plasma levels on NE, LH, FSH, PRL, and GH were measured in all samples. The administration of 12.5 ng/kg/min over 60 min of NE induced a significant increase (p less than 0.001) in plasma NE levels (n = 5) from a mean (+/- SE) baseline of 239 +/- 14 ng/L to 706 +/- 54 ng/L which peaked and plateaued at 40 min. The calculated area under the curve was 18562 +/- 3537 ng/L/h of NE and significantly higher (p less than 0.001) than during the h before the infusion (2358 +/- 780 ng/L/h). This increase in plasma NE correlated well with the rise in plasma LH which showed a steady increase from baseline of 7.4 +/- 1.3 mIU/ml to a significant (p less than 0.05) peak of 11 +/- 1.9 mIU/ml at the end of the infusion. Furthermore, analysis of the area under the curve revealed a greater (p less than 0.05) LH release during the NE infusion (180 +/- 18 mIU/ml/h) than before the infusion (92 +/- 17 mIU/ml/h). With the exception of the studies utilizing 12.5 ng/kg/min/60 min, all other doses of NE resulted in no significant and/or consistent changes in plasma concentration of LH, FSH, GH and PRL. Thus, the direct participation of NE in the control of LH secretion in humans seems to occur in a very narrow window.
Mileikowsky
G N
GN
University of Southern California School of Medicine, Department of Obstetrics and Gynecology, Los Angeles.
Farmer
R M
RM
De Quattro
V
V
Kletzky
O A
OA
D000328:Adult; D004305:Dose-Response Relationship, Drug; D005640:Follicle Stimulating Hormone / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007275:Injections, Intravenous; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009638:Norepinephrine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D010907:Pituitary Hormones / Q000378:metabolism*; D011388:Prolactin / Q000097:blood
D010907:Pituitary Hormones; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone; D009638:Norepinephrine