Possible Interaction: Dehydroepiandrosterone and Gonadotropin-Releasing Hormone

“… DHEA induces a 2.4-, … 0.3 nM LHRH , the effect being exerted at respective 50% maximally effective concentrations (ED50 values) of 0.015, 45 and 115 nM. Following …-diol or 1 microM DHEA, the maximal LH and FSH responses to LHRH are increased by approx 50% above control.”

“Serum and IT ADD and IT DHEA are markedly suppressed with GnRH administration and stimulated by hCG, but serum DHEA is not, suggesting that most circulating DHEA is not of testicular origin.”

“We hypothesized that serum and IT androstenedione (ADD) and IT dehydroepiandrosterone DHEA ) would be significantly suppressed by the administration of a GnRH antagonist and increased when stimulated by hCG, without a similar suppression of serum DHEA.”

“Serum allopregnanolone and P, but not DHEA , significantly increased in response to a GnRH test, whereas corticotropin-releasing factor and ACTH tests elicited a significant increase in allopregnanolone, P, and DHEA levels (P < 0.01).”

“In the young female, DHEA produced a 11% increase in GnRH mRNA, whereas, in the aged animals, hybridization signal was decreased by 28%.”

“ DHEA (10(-4) M) downregulates GnRH transcription by 39, 70 and 83% at 24, 36, and 48 h, respectively, while DHEA-sulphate had no effect.”

“Our studies indicate that DHEA has direct effects on GnRH transcription that appear to be unique from those observed after conversion to other steroidogenic compounds.”

“In sham-operated animals, DHEA decreased GnRH mRNA levels induced by orchiectomy.”

“These data clearly indicate that DHEA administration can modify neuronal GnRH gene expression in adult rats of both sexes, the effect being inhibitory in the male and stimulating in the female.”

“This modulation of GnRH neuronal activity, which is probably exerted following the conversion of DHEA into active sex steroids, might be at least partly responsible for modifications of the activity of the hypothalamo-pituitary-gonadal axis induced by DHEA.”

“Serum levels of dehydroepiandrosterone , androst-5-ene-3 beta,17 beta-diol, androstenedione and androstane-3 alpha, 17 beta-diol were 75 to 95% inhibited by the LHRH agonist while serum testosterone and dihydrotestosterone concentrations were reduced below detection limits by the same treatment.”