PubMed · 13956938
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S L ISRAEL. 1962. Hypothlamus function and reproduction.. https://doi.org/10.1097/00006250-196212000-00003
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Infertility may affect one in six couples; however, the development of the assisted reproduction technique (ART) created the opportunity for a large proportion of the infertile population to bear children. Pharmacological agents are routinely used in ART, and new ones are introduced regularly, with the aim of retrieving multiple oocytes to increase the prospect of pregnancy. The combinations of drugs that are used have specific adverse effects, but it is mostly the combined action of more than one agent that causes the greatest concern. The matter is complicated by the suspicion that some techniques in ART, for example intracytoplasmic sperm injection for severe male infertility problems (including azoospermia), may also contribute to the increase in adverse effects, especially congenital malformation. Gonadotropin releasing hormone (GnRH) agonists are widely used in controlled ovarian hyperstimulation. It may give rise to a short period of estradiol withdrawal symptoms and it may also lead to luteal phase deficiency. Similarly GnRHa antagonists, which have been recently introduced to control ovarian hyperstimulation, can lead to luteal phase deficiency and may cause some local injection site reactions. The more pure form of gonadotropin leads to less local injection site reactions and their main adverse effects are associated with the consequences of multiple ovulations. It has been proposed that gonadotropins may be a factor in the increasing risk of ovarian cancer and possibly breast cancer, but this has not been substantiated. Prion infection is another potential hazard, although no cases have been reported. Ovarian hyperstimulation syndrome is a well recognised complication of controlled ovarian hyperstimulation in ART. It is usually a result of recruitment of a large number of ovarian follicles. Efforts to minimise the incidence of this syndrome and its severity are now well developed. Congenital malformations are another possible adverse effect of fertility drugs, but it is more probable that the increase in congenital abnormality that is reported in ART is because of the population studied, i.e. patients already at high risk of congenital malformation, rather than the fertility drugs used or the technique employed. High order multiple pregnancy and its sequela is a well established complication of controlled ovarian hyperstimulation. This could be a result of multiple ovulations or more than one embryo replacement. Reducing the number of embryos transferred can reduce this more serious adverse effect for expectant mothers and for children conceived from ART.
Over the past 15 years, there has been a marked increase in the use of ovulation induction and intrauterine insemination (IUI) for the treatment of unexplained infertility. However, although ovulation induction and IUI have rapidly gained popularity, clinical use is based largely on practical experience rather than on well-designed scientific studies. This article summarizes the evidence in this area. Despite clinical heterogeneity and different methodological qualities of the trials, it can be concluded that ovulation induction significantly improves the probability of conception in couples with unexplained infertility, particularly when associated with IUI. It is remarkable, though, that there has been only one large-scale, randomized trial of ovulation induction plus IUI in the treatment of unexplained infertility in which one of the study arms is an untreated control group. For couples requiring treatment, the complication rate must be minimized, particularly the occurrence of high-order multiple pregnancy. Evaluation of the effectiveness and safety of low-dose gonadotrophin administration in patients with unexplained infertility is limited and further studies are warranted.
One of the crucial steps in the biosynthesis of multisubunit proteins is their assembly. The glycoprotein hormone, thyroid-stimulating hormone, and the gonadotropins, luteinizing hormone, follicle-stimulating hormone and chorionic gonadotropin, are noncovalent heterodimers. Their assembly is critical for bioactivity because the heterodimers, but not the monomeric subunits, efficiently bind to and activate the cognate heptahelical receptor. Occasionally, mutated subunits cannot combine into a functional hormone, or the bioactivity of the assembled, yet modified, heterodimer is suboptimal.