Renal excretion of zinc in patients with chronic uremia

Though uremic patients have been reported to have subnormal zinc levels in plasma and an abnormal zinc metabolism, data on their renal excretion of zinc are still unavailable. In our study, 55 nondialyzed uremic patients had a markedly lower concentration of zinc in plasma and a lower urinary zinc excretion. They had a higher excretory fraction of zinc in the renal tubules and a higher ratio of zinc to creatinine excretion than normal subjects. We found that the total daily excretion of zinc, calcium, phosphate and ammonia was reduced, and that the ratio of calcium or ammonia to creatinine excretion decreased in uremic patients. Urinary zinc excretion was correlated with renal creatinine clearance (r = 0.50, p less than 0.001) in both normal subjects and uremic patients, but ammonia excretion was correlated with zinc excretion in normal subjects only. In uremia, urinary zinc excretion was correlated with urinary calcium (r = 0.55, p less than 0.001) and urinary phosphate excretion (r = 0.30, p less than 0.05). We conclude that the increased ratio of zinc to creatinine excretion and the excretory fraction of zinc in the renal tubules of uremic patients may increase the urinary zinc excretion, but a severe diminution of the glomerular filtered load of zinc may be the major factor in decreasing the urinary zinc excretion in uremia.     

Basal and gonadotropin releasing hormone-stimulated gonadotropin secretion in patients with chronic uremia

In 11 patients with chronic uremia both the basal and stimulated levels of LH and FSH in serum were determined by RIA. After renal transplantation the investigations were repeated in 2 cases. The basal levels of LH were unphysiologically increased whereas FSH was found in the normal range. The stimulation of LH by GnRH was adequate in 6 patients and in 5 there was no response. As a result of renal transplantation there was a drop of LH in serum. It is supposed that the unphysiological increase of LH in patients with chronic uremia is the cause for the disturbances of the menstrual cycle.     

Characterization and purification of a placental protein that inactivates GnRH, TRH and angiotensin II

A protein that inactivates the immunoreactivity of GnRH, TRH and angiotensin II has been isolated from human term placentae. Only in the presence of DTT, a sulphydryl agent, are OXY and SRIF also inactivated by this protein. However, it is without effect on CRF, hCS, or hCG. It also inhibits the biological activity of GnRH, i.e. its ability to stimulate pituitary LH and FSH. The ability of this protein to inactivate GnRH, TRH or angiotensin II can be inhibited by various peptidase inhibitors. Thus, we have postulated that it is a chorionic peptidase, specific for these peptides, and herein called chorionic peptidase-1 (C-ase-1). Isolation of this protein, C-ase-1, has been effected using permeation, ion exchange and affinity chromatography. As estimated by SDS-PAGE and HPLC analyses, C-ase-1 has an apparent molecular weight of 58,000. It is proposed that C-ase-1 may be an important chorionic regulator of GnRH, TRH and angiotensin II levels during pregnancy.     

Beneficial effects of GnRH agonist administration prior to ovarian stimulation for patients with a short follicular phase

A short follicular phase is an early clinical feature of declining reproductive competence. The shortening of the follicular phase length is related to both advanced recruitment and selection of the dominant follicle secondary to an earlier and higher FSH rise during the luteal-follicular transition, while the late follicular growth is normal. As a short follicular phase may be detrimental for reproduction, it was postulated that increasing the duration of follicular phase could improve conception rate. For that purpose, gonadotrophin-releasing hormone agonist minidoses were administered in the mid-luteal phase to prevent the intercycle FSH rise before tailoring follicular growth by controlled exogenous FSH administration. This regimen, applied to 69 infertile ovulatory women with a short follicular phase (9.6 +/- 1.2 days) actually lengthened the follicular phase by about 3 days. It proved to be effective in 179 cycles to induce paucifollicular development (1.8 +/- 0.9 follicles) with a low cancellation rate (4%) and a moderate requirement for gonadotrophins [13.3 +/- 6.3 ampoules (75 IU)]. In those women with a high frequency (80%) of elevated basal FSH or oestradiol concentrations, the pregnancy rate reached 15.1%/cycle but the miscarriage rate remained high (44%). Thus, increasing the follicular phase length in patients with a short follicular phase may partially restore fecundity.     

Basal and TRH stimulated TSH secretion and determination of total thyroxine (T4). Thyroxine-binding capacity and free thyroxine index (FT4-I) in patients with chronic uremia

In 11 patients with chronic uremia both the basal and TRH stimulated TSH levels and T4, TBC and FT4-I were determined. The investigations were repeated in 2 cases after renal transplantation. TSH and T4 in serum were determined by RIA, TBC by radio reagent assay. FT4-I was calculated. In 8 patients the basal TSH levels were in the normo- and in 3 in the hypothyreotropic range. In 9 patients the response to TRH was adequate. There were deviations from the physiological range in 7 patients for T4 and in 6 for FT4-I.     

Luteal phase oestradiol administration in ovarian stimulation cycles with GnRH antagonist is comparable to the GnRH agonist (long) protocol

Purpose: The purpose of the study was to compare the effectiveness of GnRH antagonist with luteal phase estradiol administration to GnRH agonist cycles, long protocol. Methods: 55 IVF-ICSI patients received oestradiol in the luteal phase of the cycle, before a cycle with GnRH antagonist. Fifty-five patients submitted to IVF-ICSI with the use of agonist were allocated, age matched, as a control group (historical control). The primary outcome was the number of retrieved oocytes. Results: Patients were similar in terms of clinical characteristics. No differences were found in the number of oocytes retrieved (study group, 8.1 ± 4.7; control group, 7.4 ± 4.5) or in oocyte quality. Conclusions: We clearly demonstrated that the effectiveness of GnRH antagonist when combined with luteal phase estradiol is comparable to GnRH agonist cycles. Capsule Oestradiol associated to GnRH antagonist may increase the rates of oocytes causing reproductive results to be comparable to the results with the use of agonists.     

GnRH antagonist versus follicular-phase single-dose GnRH agonist protocol in patients of normal ovarian responses during controlled ovarian stimulation

Objective: This study aims to explore the differences of the ovarian stimulation (OS) characteristics, laboratory, and clinical outcomes between follicular-phase single-dose gonadotropin-releasing hormone (GnRH) agonist protocol and GnRH antagonist protocol during controlled ovarian hyperstimulation (COH).

Methods: About 1883 consecutive IVF/ICSI fresh cycles of normal ovarian responders were retrospectively analyzed, with 1229 in the single-dose GnRH agonist protocol group and 654 in the GnRH antagonist protocol group at Reproductive Medical Center of Tongji Hospital from 1 January 2014 to 31 December 2017.

Results: The follicular-phase single-dose GnRH agonist group showed significantly more oocytes obtained, higher implantation rate and pregnancy rate, as well as lower luteinizing hormone (LH) level and estradiol (E2)/oocyte ratio on the day of human chorionic gonadotropin (hCG) administration. However, differences were not significant in meiosis II (MII) oocyte rate, two pronuclear zygote (2PN) embryo rate, viable embryo rate or high-quality embryo rate, compared with the GnRH antagonist group. Further comparison of clinical outcomes in the first frozen-thawed cycles did not show significant difference in either implantation or clinical pregnancy rate between the two protocol groups.

Conclusions: Follicular-phase single-dose GnRH agonist protocol may achieve better clinical outcomes in normal ovarian responders, which could be explained more by positive effect on endometrial receptivity rather than embryo quality.     

GnRH agonist versus GnRH antagonist in ovarian stimulation: the role of endometrial receptivity

To examine whether the choice of the GnRH analogues used during controlled ovarian hyperstimulation (COH), may influence endometrial receptivity, we studied 712 IVF cycles, in patients undergoing COH with GnRH agonist or antagonist and with the transfer of at least one top-quality embryo. The GnRH agonist group showed significantly higher endometrial thickness and higher pregnancy rate, suggestive of a higher endometrial receptivity, compared with the GnRH antagonist group.     

Stimulation test of the adenohypophysis with arginine, gonadotropin-releasing hormone (GRH), and thyrotropin-releasing hormone (TRH) in 45, XO patients with Turner's syndrome (author's transl)

Pituitary stimulation tests with arginine, gonadotropin-releasing hormone (GRH) and thyrotropin-releasing hormone (TRH) were performed in five 45, XO patients with Turner's syndrome. Their ages ranged from 12--17 years. Serum levels of LH, FSH, PRL, HGH, and TSH were measured by RIA. The hypothalamo-pituitary system appeared normal in the patients with Turner's syndrome.     

Ovarian stimulation in women with high and normal body mass index: GnRH agonist versus GnRH antagonist

In modern society, obesity has become a major health problem and has been associated with impaired fertility. The aim of this study is to assess the role of obesity in women undergoing controlled ovarian hyperstimulation (COH) stimulated either with GnRH agonists or with GnRH antagonists. Records of 463 women undergoing in vitro fertilization (IVF) treatment were reviewed. The influence of body mass index (BMI) on treatment outcome was examined, after accounting for differences in stimulation protocols. In the agonist group (286 patients), the total amount of gonadotropins used was significantly higher in patients with a BMI ≥ 25?kg/m², when compared to those with a normal BMI. The same result was found in the antagonist group (177 patients). No significant differences were found in length of stimulation, number of oocytes retrieved or number of embryos transferred. In both the antagonist and the agonist group, the number of clinical pregnancies was found to be higher in patients with normal BMI, suggesting that obesity could impair the ovarian response to exogenous gonadotropins. Considering the results obtained and the many theoretical advantages of GnRH antagonists, ovarian stimulation with GnRH antagonists is an efficient treatment for both women with normal and high BMI.     

Pituitary gonadotropin responsiveness to repeated gonadotropin releasing hormone (GnRH) stimulations in patients with chronic anovulation.

To evaluate whether repeated gonadotropin releasing hormone (GnRH) stimulations were superior to single GnRH administrations for the accurate assessment of pituitary gonadotropin responsiveness, the GnRH-stimulated luteinizing hormone (LH) and follicle stimulating hormone (FSH) responses of 49 hyperandrogenic patients (HA) were compared with those of 20 hypogonadotropic patients (HH) and of 24 normally cycling women (N). Blood samples were obtained at frequent intervals during GnRH administrations (25 micrograms twice within 2 h). Unstimulated LH concentrations were higher (p less than 0.001) in HA than in N and HH women. However, basal FSH levels differed only in HA from HH women (p less than 0.001). Following either GnRH stimulation, increased (p less than 0.01) LH and FSH releases were noted in all N, HA and HH women. The GnRH-stimulated LH and FSH responses to either GnRH injections were highest (p less than 0.01) in HA and lowest (p less than 0.01 vs. N) in HH women. The net LH and FSH increases over unstimulated concentrations (delta LH or FSH) in response to either GnRH stimulation were highest (p less than 0.01 or less) in HA women. By contrast, no differences were determined in the delta LH and FSH levels between the first and second GnRH stimulations within each group. These observations document different unstimulated and stimulated gonadotropin concentrations in normal cycling and anovulatory women. Gonadotropin responses to single GnRH administrations differ for anovulatory patients. Since the gonadotropin responses to the second GnRH stimulation are comparable to those during the first GnRH injections, repeated GnRH stimulations may not help to distinguish the degree of pituitary responsiveness in ovulatory from anovulatory women.     

Comparison between stimulation with highly purified hMG or recombinant FSH in patients undergoing IVF with GnRH antagonist protocol

Purpose: Highly purified Human Menopausal Gonadotropins (hp-hMG) and recombinant FSH (rFSH) are widely used in assisted reproductive technology (ART). The aim of this study was to compare ART results of the two preparations in GnRH antagonist cycles.

Methods: In this retrospective cohort study, IVF antagonist cycles performed from 2011 through 2013 were reviewed. There were 508 antagonist cycles: 320 stimulated with rFSH and 188 with hp-hMG. For every hp-hMG, two rFSH were matched for patient's age and infertility diagnosis. Subgroup analysis of patients younger and older than 35 was done as well.

Results: Both treatments were resulted in comparable pregnancy and live birth rates. However, cumulative pregnancy rates were higher for the rFSH group. In the matching analysis, the rFSH group had more mature oocytes and more embryos while using lower doses of gonadotropins. Pregnancy, cumulative pregnancy rates, and live birth rates were comparable. In the subgroup analysis, young patients in the rFSH group had better cycle outcomes compared with those in the hp-hMG group.

Conclusion: In antagonist protocol, different gonadotropin products are equally effective. The choice of one or the other should depend on the availability, convenience of use, and cost.     

GnRH agonist versus GnRH antagonist in ovarian stimulation: the role of elevated peak serum progesterone levels

Abstract

Aim: We sought to evaluate the influence of subtle serum progesterone elevation on in vitro fertilization (IVF) cycle outcome and to assess the impact of the type of gonadotropin-releasing hormone (GnRH)-analogue used during controlled ovarian hyperstimulation (COH) on the probability of clinical pregnancy.

Patients and methods: We reviewed the files of all consecutive patients undergoing COH with either GnRH-agonist or antagonist in our IVF unit during a 10-year period and who had their peak serum progesterone levels determined on the day of human chorionic gonadotropin (hCG) administration.

Results: Of the 2244 IVF cycles evaluated, 2103 had peak progesterone level of <1.5?ng/mL (normal-P group) and 141 of >1.5?ng/mL (high-P group) (6.28% of all the study population). Clinical pregnancy rate was significantly higher in the normal-P group (25.4% versus 16.6%; p?<?0.006). Moreover, among the high-P group patients, the use of the long GnRH-agonist suppressive protocol (GnRH-ag) was more prevalent in patients who conceived as compared to those who did not (60.9% versus 39%, respectively; p?<?0.05), with a tendency toward an increase pregnancy rate in those using GnRH-ag compared with GnRH-antagonist protocol (GnRH-antag; p?<?0.059) COH protocols.

Conclusion: While subtle progesterone elevation in patients undergoing COH using GnRH-antag COH protocols, should dictate embryo cryopreservation and cancelation of the fresh transfer, in those undergoing the GnRH-ag COH protocol, a fresh embryo transfer should be recommended.     

Prolactin response to thyrotropin-releasing hormone (TRH) in patients with hypothalamic-pituitary disease

The prolactin (PRL) response to thyrotropin-releasing hormone (TRH) was evaluated in 686 patients over a 4-year period. Of the 170 control subjects tested, none had a blunted PRL response to TRH. Eighty patients with prolactinomas documented by surgery were tested. Ninety-five percent (76 of 80) of these patients had an abnormally blunted PRL response to TRH. Of the 87 patients with a prolactinoma who did not undergo surgery, 98% (85 of 87) had a blunted PRL response to TRH. Many patients with other pituitary and hypothalamic diseases (pituitary tumors other than prolactinomas [Cushing's disease, acromegaly, chromophobe adenoma], craniopharyngioma) also had an abnormal PRL response to TRH (79 of 153, 52%). In the majority of patients with hyperprolactinemia due to dopamine antagonist medications, TRH stimulation did not produce a normal rise in PRL. The TRH test may be helpful in confirming the diagnosis of prolactinoma, but it is not a decisive factor in the diagnosis or management of this entity.     

GnRH antagonists in ovarian stimulation for ICSI with oocyte restriction: a matched, controlled study

Italian legislation regarding reproductive medicine limits the number of embryos transferred per attempt to three. Thus, in order to achieve pregnancy, more IVF cycles may be required, generating a need for methods of ovarian stimulation with fewer side effects. The gonadotrophin-releasing hormone (GnRH) antagonists have several advantages in this respect, but there is a debate regarding a possible lower pregnancy rate from resulting cycles. This study evaluated the clinical applicability of GnRH antagonists for ovarian stimulation in young women undergoing intracytoplasmic sperm injection (ICSI) in which only three oocytes can be fertilized. The 200 women treated with GnRH antagonist had a significantly shorter stimulation and lower gonadotrophin consumption, oestradiol concentration, total and mature oocyte recovery as compared with 200 matched controls treated with GnRH agonist. No differences were found between the groups in the number of normal zygotes, total cleaved, transferred and high quality embryos, or in the clinical outcomes. Thus, the previously reported lower pregnancy rate in GnRH antagonist cycles may be related to the oocyte characteristics. Finally, under conditions of oocyte number restriction, the GnRH antagonist-based cycles may be proposed as an efficacious, safe and minimally invasive alternative to GnRH agonist in a standard long protocol.     

Comparison of GnRH antagonist with long GnRH agonist protocol after OCP pretreatment in PCOs patients

Purpose  

To evaluate the efficacy of GnRH antagonist in comparison with the GnRH agonist protocol in OCP pretreated polycystic ovary syndrome (PCOs) patients undergoing their first ART cycle.     

Use of GnRH antagonists in ovarian stimulation for assisted reproductive technologies compared to the long protocol

The use of GnRH antagonists has revolutionized ovarian stimulation for assisted reproduction. Two GnRH antagonists are clinically available, namely, cetrorelix and ganirelix. Several studies have directly compared these new stimulation protocols against the long GnRH agonist protocol. To evaluate whether there is a reduction in cases of ovarian hyperstimulation syndrome (OHSS) and/or a reduction in pregnancy rates, a meta-analysis was performed. There was a significant reduction of OHSS cases in the cetrorelix studies (odds ratio, OR, 0.23; 95% confidence interval, CI, 0.10-0.54), but no reduction for ganirelix (OR 1.13; 95% CI 0.24-5.31). The incidence of OHSS degree III cases was reduced in the cetrorelix protocols as compared to the long protocol to a nearly significant degree (OR 0.26; 95% CI 0.07-1.01). Ganirelix did not reduce the incidence of OHSS degree III at all (OR 1.08; 95% CI 0.27-4.38). The pregnancy rate per cycle was significantly lower in the ganirelix protocols than in the long protocol (OR 0.76; 95% CI 0.59-0.98). The studies using cetrorelix showed quite similar, not significantly different results for the antagonist and the long protocol groups for the pregnancy rate per cycle (OR 0.91; 95% Cl 0.68-1.22). From the data one can conclude that cetrorelix but not ganirelix will reduce the incidence of cases of OHSS and that cetrorelix but not ganirelix will result in the same pregnancy rates as the long protocol. Several possibilities to explain this phenomenon are discussed.