Testicular steroid response to continuous and pulsatile intravenous luteinizing hormone-releasing hormone administration in normal men.
In 18 healthy normal men Leydig cell response was examined following intravenous luteinizing hormone-releasing hormone (LH-RH) administration under standardized conditions. The same total amount of LH-RH was administered for 3 hours both in a continuous (1 microgram/min; C (1,1)) and in a pulsatile fashion, by giving a 20 micrograms dose at 20 minutes intervals, P (20, 20), and a 60 micrograms dose at 60 minutes intervals, P (60, 60). Following the different modes of LH-RH administration which all caused 3-4 fold elevations of the mean endogenous luteinizing hormone (LH) concentrations and 1.7-2 fold elevations of the mean follicle-stimulating hormone (FSH) serum levels, an overt increase of the mean testosterone (T) levels was noticed up to 1.5 X the baseline value. No difference was observed in the total amount of T release among the investigated groups. The patterns of the T response, however, clearly differed from one another with a rapid increase, during the C (1, 1) and the P (20, 20) LH-RH administration, and a delayed but persistent T increase in the P (60, 60) experiment. The mean 17-hydroxyprogesterone (17-OHP) concentrations demonstrated a similar course to T in the P (60,60) experiment, while significant increases of the oestradiol (E 2) levels were never observed in all three experiments. In view of the comparable LH and FSH increments in response to LH-RH administration in either experiment the differences in T responses may be explained by assuming a direct effect of LH-RH on Leydig cell steroidogenesis in the men.
Fauser
B C
BC
Smals
A G
AG
Rolland
R
R
Dony
J M
JM
Doesburg
W H
WH
Thomas
C M
CM
D019326:17-alpha-Hydroxyprogesterone; D000328:Adult; D004958:Estradiol / Q000097:blood; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D006908:Hydroxyprogesterones / Q000097:blood; D007275:Injections, Intravenous; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D013737:Testis / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000097:blood; D013997:Time Factors
D006908:Hydroxyprogesterones; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D004958:Estradiol; D019326:17-alpha-Hydroxyprogesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone