We examined the kinetically distinct characteristics of estradiol's effects upon pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release in response to pulses of exogenous gonadotropin-releasing hormone (GnRH) in healthy postmenopausal individuals. The putative self-priming actions of GnRH on LH and FSH release were tested by intravenous injections of equal paired doses of GnRH (10 micrograms) before and after 1, 5, 10, and 30 d of pure estradiol-17 beta delivery via an intravaginal silastic ring. Self-priming actions of GnRH, as defined by heightened gonadotropin release in response to the second pulse of GnRH compared with the first, were completely absent in the hypoestrogenemic state. However, estradiol administration unmasked GnRH self-priming in a time-dependent fashion, with maximal expression after 5 and 10 d of steroid replacement, followed by attenuation by 30 d. Since estradiol's modulation of GnRH action was expressed differentially on LH and FSH release, we suggest that such facilitation of GnRH-stimulated pituitary LH and FSH release may provide an additional mechanism for dissociated secretion of gonadotropic hormones in health or disease.
J D Veldhuis, W S Evans, A D Rogol, L Kolp, M O Thorner, P Stumpf
Usage data is cumulative from May 2023 through May 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 136 | 0 |
35 | 16 | |
Scanned page | 111 | 15 |
Citation downloads | 12 | 0 |
Totals | 294 | 31 |
Total Views | 325 |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.