Isoforms and single nucleotide polymorphisms of the FSH receptor gene: implications for human reproduction

The FSH receptor shows three single nucleotide polymorphisms (SNPs), one in the promoter and two in exon 10. In addition, the FSH receptor mRNA undergoes extensive alternative splicing. While no physiological role for the SNP in the promoter and for alternative spliced isoforms has been demonstrated so far, the SNPs in exon 10 result in four discrete allelic variants characterized by the amino acid combinations Thr307-Asn680, Ala307-Ser680, Ala307-Asn680 and Thr307-Ser680. Several studies have demonstrated that the first two allelic variants are very frequent (approximately 60 and 40% respectively) in the Caucasian population. The rarer Ala307-Asn680 and Thr307-Ser680 variants are much less frequent (<5%) in the Chinese. In males the FSH receptor variants are not related to testicular volume, serum FSH or serum inhibin B levels. The two most common receptor variants transiently transfected in COS-7 cells displayed similar functional characteristics. Frequency distribution of the two polymorphisms in normal women and patients with polycystic ovarian syndrome or premature ovarian failure is still under investigation. The homozygous Ala307-Ser680 variant seems to be associated with significantly higher basal serum FSH levels and with a higher amount of FSH required for ovarian stimulation in women undergoing assisted reproduction. This suggests that the FSH receptor genotype can influence the ovarian response to FSH stimulation. The presence of SNPs in the FSH receptor gene capable of modifying FSH action paves the way for future patient-tailored, genotype-based hormone therapies.     

Genetic disorders in premature ovarian failure

This review presents the genetic disorders associated with premature ovarian failure (POF), obtained by Medline, the Cochrane Library and hand searches of pertinent references of English literature on POF and genetic determinants cited between the year 1966 and February 2002. X monosomy or X deletions and translocations are known to be responsible for POF. Turner's syndrome, as a phenotype associated with complete or partial monosomy X, is linked to ovarian failure. Among heterozygous carriers of the fragile X mutation, POF was noted as an unexpected phenotype in the early 1990s. Autosomal disorders such as mutations of the phosphomannomutase 2 (PMM2) gene, the galactose-1-phosphate uridyltransferase (GALT) gene, the FSH receptor (FSHR) gene, chromosome 3q containing the Blepharophimosis gene and the autoimmune regulator (AIRE) gene, responsible for polyendocrinopathy-candidiasis-ectodermal dystrophy, have been identified in patients with POF. In conclusion, the relationship between genetic disorders and POF is clearly demonstrated in this review. Therefore, in the case of families affected by POF a thorough screening, including cytogenetic analysis, should be performed.     

Aberrant recombination and the origin of Klinefelter syndrome

Trisomy is the most commonly identified chromosome abnormality in humans, occurring in at least 4% of all clinically recognized pregnancies; it is the leading known cause of pregnancy loss and of mental retardation. Over the past decade, molecular studies have demonstrated that most human trisomies originate from errors at maternal meiosis I. However, Klinefelter syndrome is a notable exception, as nearly one-half of all cases derive from paternal non-disjunction. In this review, the data on the origin of sex chromosome trisomies are summarized, focusing on the 47,XXY condition. Additionally, the results of recent genetic mapping studies are reviewed that have led to the identification of the first molecular correlate of autosomal and sex chromosome non-disjunction; i.e. altered levels and positioning of meiotic recombinational events.     

Terminology associated with vitrification and other cryopreservation procedures for oocytes and embryos

Over the past 30 years many cryopreservation procedures have been applied to oocytes, embryos, sperm, ovarian and testicular tissue. Over this time many, often specialized, terms have been developed for all aspects of these procedures. This can make it difficult for readers who are not familiar with the terminology or protocols to compare and evaluate different procedures. This paper describes the main cryopreservation procedures, the terminology associated with them, and briefly explains the underlying physical, chemical and biological processes. The aim is to help readers understand and interpret other papers on slow cooling, rapid cooling, ultrarapid cooling and vitrification.     

Patient predictors for outcome of gonadotrophin ovulation induction in women with normogonadotrophic anovulatory infertility: a meta-analysis

A systematic review was conducted to determine whether initial screening characteristics of women with normogonadotrophic anovulatory infertility predict clinically significant outcomes of ovulation induction with gonadotrophins, and to obtain pooled estimates of their predictive value through meta-analysis. Only those studies in which pre-treatment screening characteristics (such as body mass index, serum LH and androgens, insulin sensitivity and ultrasound appearance of ovaries) were related to outcome parameters (such as total amount of FSH administered, cancellation, ovulation, pregnancy and miscarriage), were included in this analysis. Thirteen studies fulfilled the inclusion criteria. A positive association was seen in all studies between the level of obesity (definition applied as assessed by individual studies) and total amount of FSH administered [weighted mean difference (WMD) of 771 IU (95% confidence interval (CI): 700-842)]. Pooled odds ratios (OR) of 1.86 (95% CI: 1.13-3.06) and 0.44 (95% CI: 0.31-0.61) were found between obesity with cancellation and ovulation respectively. Pooled analysis did not show a significant association between obesity and pregnancy rate. The pooled OR for obese versus non-obese women and miscarriage rate was significant [3.05 (95% CI: 1.45-6.44)]. Association measures between insulin resistance (definition applied as assessed by individual studies) and total amount of FSH administered produced a WMD of 351 (95% CI: 73-630) IU. A pooled OR of 0.29 (95% CI: 0.10-0.80) was found for insulin resistance with pregnancy rate. The pooled OR for insulin resistance (hyperinsuliaemia versus normoinsuliaemia) and miscarriage rate was not significant. A pooled OR of 1.04 (95% CI: 1.01-1.07) was found for LH (IU/l) with pregnancy rate. The pooled OR for LH and miscarriage rate was not significant. Finally, pooled analysis did not find a significant association between testosterone and pregnancy rate. In conclusion, the best available evidence, though limited, suggests that the most clinically useful predictors of gonadotrophin ovulation induction outcome in normogonadotrophic women are obesity and insulin resistance.     

ACE inhibition modulates transforming growth factor-β receptors in the young rat

The renin-angiotensin system plays an important role in renal growth and development. Exposure of the neonate to angiotensin converting enzyme (ACE) inhibitors increases mortality and results in growth retardation and abnormal renal development. It has been demonstrated that ACE inhibition in the developing kidney reduces the renal expression of growth factors, which may account for renal growth impairment. This study was designed to investigate the relationship between renal growth impairment and the expression of transforming growth factor-1 (TGF-1), TGF- receptor I [TRI, activin-like kinase (ALK)-1 and ALK-5], and TGF- receptor II (TRII). Newborn rat pups were treated with enalapril (30 mg/kg per day) or vehicle for 7 days, and kidneys were removed for Western blotting of TGF-1, ALK-1, ALK-5, and TRII, and for RT-PCR of ALK-5 and TRII. TGF-1, ALK-1, ALK-5, and TRII were also detected by immunohistochemistry. Enalapril treatment resulted in an increased mortality (30.4%) by day 7, and reduced body weight and kidney weight (P<0.05 versus vehicle). Enalapril decreased renal TGF-1, ALK-1, and ALK-5 protein expression (P<0.05). Also, enalapril decreased ALK-5 mRNA expression (P<0.05). TRII expression was not changed by enalapril treatment. These results indicate that ACE inhibition in the developing kidney decreases TGF-1, ALK-1, and ALK-5 expression, which may account for renal growth impairment. TRII may not be modulated by ACE inhibition in the developing kidney.     

Reduced Phagocytosis of Colloidal Carriers Using Soluble CD47

Purpose. This study was designed to illustrate the feasibility of using soluble CD47 protein to antagonize phagocytosis of colloidal drug carriers by macrophages. Methods. Expression of CD47-streptavidin (CD47-SA) fusion protein was achieved in B21CodonPlus host cells following IPTG induction. Murine macrophage cell line J774A.1, expressing high levels of SIRP, was selected as the biologic model system for phagocytosis. FITC-labeled perfluorocarbon (PFC) emulsions were used as the colloidal carriers to trigger phagocytosis. Microscopy (inverted light and UV-fluorescence) and flow cytometry were used to qualitatively and quantitatively determine the degree of phagocytosis, respectively. Results. The bacterially expressed, purified CD47-SA had neither cytotoxic nor cytostatic effects when incubated with J774A.1 cells up to a concentration of 400 nM for 24 h. Phagocytosis of FITC-labeled PFC emulsions was significantly diminished when macrophages were pretreated with 100 nM CD47-SA for 1 h. Conclusions. We demonstrated that soluble CD47-SA antagonized phagocytosis of colloidal carriers to a significant degree by interaction with macrophage SIRP.     

Metabolism of SFZ—47 in chicken embryo by liquid chroma—tography—electrospray ion trap mass spectrometry

AIM:To develop an alternative method for investigation of drug metabolism by fertilized chicken eggs using 3H-1,2-dihydro-2-(4-methyl-phenylamino) methyl-1-pyrrolizinone (SFZ-47) as a probe drug. METHODS:SFZ-47(15 mg) was injected into the albumen of eggs from standardized breed chickens previously incubated for 10d. After 72 h of further incubation, the allantoic liquid was subjected to solid phase extraction on XAD-2 columns and analyzed by liquid chromatography-electrospray ion trap mass spectrometry method. RESULTS: Three major metabolites were identified, namely 4-(3H-1,2-dihydro-1-pyrrolizinone-2-methyl-amino) benzyl alcohol (SFZ-47-OH), 4-(3H-1,2-dihydro-1-pyrrolizinone-2-methyl-amino)-benzoic acid (SFZ-47-COOH), and its glucuronide conjugates. The metabolic profile was little different from that previously found in rabbits and dogs. CONCLUSION: The result demonstrates the usefulness of the fertilized chicken egg as a convenient source of both phase I and phase Ⅱ metabolites for further metabolism studies of SFZ-47.     

The impact of endocrine disrupters on the female reproductive system

Over the last decades, many tonnes of man-made chemicals have been produced and released into the environment. Many of these chemical substances have the ability to modulate the action of hormones and are called endocrine disrupters. Cell receptors that have been pure receptors for thousands of years have (due to industrialization), become susceptible to the action of exogenous chemicals. The balance of the endocrine system is very important in the human body especially in females because the menstrual cycle and fertility are very sensitive to hormone imbalances. This review considers the mode of exposure and action of endocrine disrupters and focuses on their impact on the female reproductive system, including female hormone concentrations, menstrual cycle, fertility, spontaneous abortion and the development of endometriosis. An attempt is made to elucidate the impact of endocrine disrupters on the female reproductive system, while admitting that most scientific data come from experimental animals and the conclusions cannot be applied to humans easily. The aim is to present available information, highlighting the impact of endocrine disrupters on the female reproductive system, in order to stimulate reevaluation in identifying hormone disorders.     

Possible health impact of animal oestrogens in food

Oestrogens govern reproductive functions in vertebrates, and are present in all animal tissues. The theoretical maximum daily intake (TMDI) of oestradiol-17beta by consumption of cattle meat is calculated to be 4.3 ng. Following the use of oestradiol-containing growth-promoting agents, TMDI is increased by a factor of 4.6 to 20 ng oestradiol-17beta, assuming that single dosage and 'good animal husbandry' are observed. Pork and poultry probably contain similar amounts of oestrogens as untreated cattle. The mean concentration of oestradiol-17beta in whole milk is estimated at 6.4 pg/ml. Scarce data available on eggs report up to 200 pg/g oestradiol-17beta. The risk evaluation of oestrogenic growth-promoting agents is limited by analytical uncertainties. Residues of oestradiol-17alpha and the importance of oestrogen conjugates are widely unknown. The performance of mass spectrometry still needs to be improved for confirmation of oestrogen concentrations in most food. At present, the potential relevance of oestradiol acyl esters, the actual daily production rate of oestradiol in prepubertal children, and the role of oestradiol metabolites in cancer are obscure. The presence of different cytoplasmic oestrogen receptor subtypes and potential oestradiol effects in non-reproductive functions require further examination.