Luteinizing Hormone-releasing Hormone Agonist Injection Research Articles

Transcriptomic evidence of luteinizing hormone-releasing hormone agonist (LHRH-A) regulation on lipid metabolism in grass carp (Ctenopharyngodon idella)

In this study, RNA sequencing was used to identify the hepatic gene expression profile in grass carp associated with luteinizing hormone-releasing hormone agonist (LHRH-A) treatment. A total of 93,912,172 reads were generated by HiSeq 4000 sequencing platform. After filtering, 83,450,860 clean reads were mapped to the reference genome. By calculating the FPKM of genes, 1475 differentially expressed genes were identified. PPAR signaling pathway was enriched with upregulated genes in LHRH-A injection group showing the regulation of the lipid metabolism by LHRH-A. The expression of eight key genes in PPAR signaling pathway was confirmed by qPCR and the results suggested that ACSL4A, ACSL4B, ANGPTL4, LPL, RXRBA and SLC27A1B were significantly stimulated by LHRH-A injection. This investigation provides the evidence that LHRH-A could play a role in lipid metabolism.

New treatment paradigm for prostate cancer: abarelix initiation therapy for immediate testosterone suppression followed by a luteinizing hormone‐releasing hormone agonist

Study Type - Therapy (prospective cohort). Level of Evidence 2a. What's known on the subject? and What does the study add? The sequential administration of a GnRH antagonist followed by an LHRH agonist in the management of prostate cancer patients has not been studied, but such a program would provide a more physiologic method of achieving testosterone suppression and avoid the obligatory testosterone surge and need for concomitant antiandrogens that accompany LHRH agonist therapy. The current study which uses abarelix initiation therapy for 12 weeks followed by either leuprolide or goserelin demonstrates the ability to more rapidly achieve testosterone suppression, avoid the obligatory LHRH induced testosterone surge, avoid the necessity of antiandrogens, all of which were accomplished safely, without inducing either additional or novel safety issues. • To demonstrate the safety and endocrinological and biochemical efficacy of initiating treatment with the gonadotropin-releasing hormone (GnRH) antagonist, abarelix, followed by administration of an luteinizing hormone-releasing hormone (LHRH) agonist in patients with advanced and metastatic prostate cancer. • A multicentre, open-label design study was conducted at 22 centres in the US involving patients with: localized, locally advanced or metastatic disease; with a rising prostate-specific antigen (PSA) after definitive local treatment; patients undergoing neoadjuvant hormonal therapy before local therapy (radical prostatectomy, radiation therapy or cryosurgery); and patients in whom intermittent therapy was the planned treatment. • All patients received abarelix for 12 weeks followed by an LHRH agonist (either leuprolide or goserelin) for 8 weeks • The primary efficacy endpoint was achievement and maintenance of castration defined as testosterone <50 ng/dL from day 29 through to day 141 and whether abarelix initiation therapy could eliminate the testosterone surge after two consecutive doses of LHRH agonist therapy. • PSA, LH and follicle-stimulating hormone (FSH) levels were measured and adverse events were monitored. • A total of 176 patients were enrolled into the present study, the majority of whom had localized prostate cancer (82%) and a PSA level <10 ng/mL (62%). • At the end of the abarelix treatment period (day 85), 93.8% of patients achieved castrate levels; during the first week of switch over to the LHRH agonist therapy (days 85-92) the rate was 86.5% and during the week after the second LHRH agonist injection (days 114-12) it was 93.3%. • A small, transient increase in testosterone occurred during the first injection of the LHRH agonist; mean (standard deviation [sd]) values increased from 17 (17.8) ng/dL at day 85 to 37.3 (51.07) ng/dL at day 86. • Mean (sd) PSA levels decreased from 20.5 (56.6) ng/mL at baseline to 3.7 (23.5) ng/mL on day 85 and remained stable throughout the LHRH agonist treatment phase. • Treatment-related adverse events occurred in 84% of patients overall; a similar incidence was reported during the two treatment phases. • Abarelix initiation therapy results in the desired effect of achieving rapid testosterone suppression; testosterone surges after subsequent LHRH agonist therapy are greatly abrogated or completely eliminated. • This treatment paradigm (abarelix initiation followed by agonist maintenance) obviates the need for an antiandrogen. • Abarelix was well tolerated and no clinically meaningful or novel adverse events were observed during abarelix treatment or in the transition to LHRH agonist maintenance therapy.

Testosterone and erectile function recovery after radiotherapy and long‐term androgen deprivation with luteinizing hormone‐releasing hormone agonists

To study the recovery of testosterone levels and erectile function in men who received radiotherapy plus long-term adjuvant androgen deprivation (LTAD) with luteinizing hormone-releasing hormone (LHRH) agonists. From April 2000 to July 2001, men who had completed prostate radiotherapy with > or = 2 years of LTAD, and had their last LHRH agonist injection at least 6 months before, were invited to participate. At study entry, the men completed the International Index of Erectile Function (IIEF), and their serum total testosterone (TT), prostate-specific antigen, LH, follicle-stimulating hormone, haemoglobin, and body mass were measured. This assessment was repeated at 1 year. In all, 20 men were recruited, with a mean (range) age of 70 (55-81) years. Defining a normal TT level as > or = 8.0 nmol/L, the median time to a normal level was 2.3 years (95% confidence interval (CI), 1.9-4.2). The median duration of castrate TT levels was 8 months (95% CI, 6.2-14.9). LH recovered before TT, suggesting that the rate-limiting step in the recovery of TT may be at the testicular level. The median time to recovery of normal LH levels was 3.8 months, compared to 8.0 months to reach supracastrate TT levels, and 2.3 years to reach normal TT levels. Age and the LH/TT ratio were associated with the time to recovery of both supracastrate and normal levels of TT. The IIEF was completed by 17 men; there were no significant changes in the scores in any domain of the IIEF during the study. Most men recover supracastrate testosterone levels after LTAD and external beam radiotherapy, but recovery of 'normal' testosterone levels is slow. Few men recover potency and sexual desire. The patients age and LH/TT ratio may be predictive of the time to recovery of both supracastrate and normal testosterone levels.

Failure to achieve castrate levels of testosterone during luteinizing hormone releasing hormone agonist therapy: the case for monitoring serum testosterone and a treatment decision algorithm.

We report the failure to achieve a castrate level of testosterone associated with 3-month depot luteinizing hormone releasing hormone (LH-RH) agonist therapy, which to our knowledge is a previously unrecognized outcome. We prospectively enrolled in our study 38 men with prostate cancer on 3-month depot LH-RH agonist therapy. We monitored total serum testosterone and prostate specific antigen every 28 days beginning 90 days after the last depot LH-RH agonist injection. Data were analyzed with castrate testosterone defined as less than 50 and 20 ng./dl. or less. Using the 50 and 20 ng./dl. definitions of castrate testosterone 2 (5%) and 5 (13%) of the 38 men, respectively, failed to achieve castrate testosterone. A patient with a nadir testosterone of 70 ng./dl. subsequently underwent orchiectomy and testosterone decreased to 10 ng./dl. thereafter. A small but potentially important subgroup of men on depot LH-RH agonist therapy fail to achieve a castrate level of testosterone. Our findings support monitoring testicular response when LH-RH agonist therapy is initiated.

FAILURE TO ACHIEVE CASTRATE LEVELS OF TESTOSTERONE DURING LUTEINIZING HORMONE RELEASING HORMONE AGONIST THERAPY: THE CASE FOR MONITORING SERUM TESTOSTERONE AND A TREATMENT DECISION ALGORITHM

Purpose: We report the failure to achieve a castrate level of testosterone associated with 3-month depot luteinizing hormone releasing hormone (LH-RH) agonist therapy, which to our knowledge is a previously unrecognized outcome.Materials and Methods: We prospectively enrolled in our study 38 men with prostate cancer on 3-month depot LH-RH agonist therapy. We monitored total serum testosterone and prostate specific antigen every 28 days beginning 90 days after the last depot LH-RH agonist injection. Data were analyzed with castrate testosterone defined as less than 50 and 20 ng./dl. or less.Results: Using the 50 and 20 ng./dl. definitions of castrate testosterone 2 (5%) and 5 (13%) of the 38 men, respectively, failed to achieve castrate testosterone. A patient with a nadir testosterone of 70 ng./dl. subsequently underwent orchiectomy and testosterone decreased to 10 ng./dl. thereafter.Conclusions: A small but potentially important subgroup of men on depot LH-RH agonist therapy fail to achieve a castrate le...

Serum testosterone-based luteinizing hormone-releasing hormone agonist redosing schedule for chronic androgen ablation: a phase I assessment

Objectives. To assess the potential for using the serum testosterone level as the guide for redosing depot luteinizing hormone-releasing hormone (LHRH) agonist and to characterize the duration of castrate level testosterone after the last 22.5-mg leuprolide injection repeatedly administered for the control of prostate cancer. Methods. Informed consent was obtained from 32 men with prostate cancer (Stage T3N± M± or greater) treated with 3-month (22.5-mg) leuprolide acetate injection. Serum testosterone and prostate-specific antigen levels were obtained every 28 days beginning on the 90th day after the last 22.5-mg leuprolide injection. The duration of action was the calculated interval, in months, between the last injection and the first noncastrate serum testosterone (greater than 0.2 ng/mL) value. Results. The median duration of castrate level testosterone was 6.0 months (SE ± 0.15; upper and lower quartile 5.3 and 7.0, respectively). Prostate cancer biochemical (prostate-specific antigen) activity at enrollment and when the castrate testosterone threshold of 0.2 ng/mL was exceeded remained stable, with no significant change observed during this interval ( P = 0.52). A significant association was observed between an increasing duration of castration after LHRH agonist injection and advancing patient age ( P = 0.03) and increasing duration of hormonal therapy ( P = 0.05). Conclusions. These results suggest that using the serum testosterone level to guide in redosing of long-acting LHRH agonist may provide a novel, effective, and economical method to administer hormonal ablative therapy in patients with prostate cancer. These observations have important implications for product dosing and the design and interpretation of neoadjuvant and intermittent androgen ablative trials.

TIME TO NORMALIZATION OF SERUM TESTOSTERONE AFTER 3-MONTH LUTEINIZING HORMONE-RELEASING HORMONE AGONIST ADMINISTERED IN THE NEOADJUVANT SETTING: IMPLICATIONS FOR DOSING SCHEDULE AND NEOADJUVANT STUDY CONSIDERATION

Purpose A time course to serum testosterone normalization after administration of a single 3-month luteinizing hormone-releasing hormone (LH-RH) agonist in the neoadjuvant setting was developed. Materials and Methods A total of 13 men with clinically localized prostate cancer were prospectively assessed for baseline libido, erectile function and mid morning serum testosterone. A single 3-month formulation LH-RH agonist was administered in the neoadjuvant setting before definitive treatment with radical perineal prostatectomy in 7 men or external beam radiotherapy in 6. Baseline and serial testosterone levels were measured 3, 4, 6, 7, 9, 12, 15 and 18 months after injection. Symptoms related to acute testosterone depletion, namely hot flashes and sweats, were recorded on the same schedule. Results After a single 3-month LH-RH agonist injection median duration of castrate level testosterone (0.2 ng./ml. or less) was 6 months. Median duration of hypogonadal symptoms (hot flashes and sweats) was 13.6 months and resolution paralleled the gradual return of serum testosterone to baseline values. Conclusions The 3-month formulation of LH-RH agonist administered in the neoadjuvant setting provides castrate level testosterone for a longer duration than the product labeling suggests. If confirmed, these preliminary observations have important implications for dosing schedule and neoadjuvant study consideration.

Plasma luteinizing hormone bioactivity and immunoactivity in ovariectomized rats treated with a long-acting agonist of luteinizing hormone releasing hormone.

The dose response of a luteinizing hormone releasing hormone (LHRH) agonist in rats with high endogenous gonadotrophin levels was determined. Female rats were ovariectomized and injected with 0.3 microgram (group B), 3.2 micrograms (group C), 32 micrograms (group D) and 320 micrograms (group E) of a slow-releasing microcapsule preparation of the LHRH agonist D-Trp 6-LHRH. Control ovariectomized rats (group A) remained untreated. Plasma luteinizing hormone (LH) concentrations were measured by radioimmunoassay (RIA) before the LHRH agonist injection as well as 5, 15 and 30 days thereafter. Furthermore, LH bioactivity was determined by an in vitro rat LH bioassay in order to evaluate changes in bioactivity after administration of LHRH agonist. In control rats, plasma LH concentrations increased to 4.8 +/- 1.3 ng/ml on day 5, reaching peak levels of 9.9 +/- 1 ng/ml on day 30. In contrast to the control group, those rats which received 320 micrograms of LHRH agonist did not show any increase. Rats which received intermediate doses (groups C and D) tended to maintain levels of LH halfway between group A and group E during the first 15 days of treatment. Thereafter LH concentrations were similar to the untreated control group. The course of the LH concentrations during treatment measured by bioassay (BA) showed a similar pattern to the LH concentrations measured by RIA. The BA/RIA ratio was similar in all groups.

Stimulation of leydig cell testoterone secretion [formula omitted] and [formula omitted] in hypophysectomized rats by an agonist of luteinizing hormone releasing hormone

Injection of a luteinizing hormone-releasing hormone (LHRH) agonist into 55-day-old male rats which had been hypophysectomized 3 days earlier resulted in a 10- to 30-fold increase in the levels of testosterone in serum and testicular interstitial fluid (IF) in the 4h following injection. The levels achieved were within or above the normal range for intact untreated rats of this age. In similar animals, injection of LHRH agonist also enhanced the serum testosterone response to injected hCG at 1 1 2 h , but not at later times after injection, and by 24h reduced IF levels of testosterone suggested that LHRH agonist had begun to inhibit stimulation by hCG. In vitro , dispersed Leydig cells from untreated hypophysectomized rats showed a 2-fold increase in testosterone responsiveness to LHRH agonist when compared to cells from intact rats, and this change was associated with an 80% increase in the number of Leydig cell LHRH-receptors.