Endocrine Abstracts

It is now possible to modify the mouse genome to generate strains of mice with precise genetic mutations. Over 50 strains of mutant mice have now been produced in which there is an alteration in female fertility (Elvin and Matzuk, Reviews of Reproduction, 1998). For example, we have shown that a knockout of the oocyte-specific TGF-beta family member, growth differentiation factor-9 (GDF-9), results in a block at the primary follicle stage (Dong et al., Nature, 1996; Carabatso...

While secretion of GnRH pulses from hypothalamic neurones every 1 to 4 h is the normal mode of release in adult males and females, resulting in pulsatile LH secretion from pituitary gonadotropes, only in females does the pattern of GnRH secretion change from pulsatile to a surge mode in response to estradiol to generate the preovulatory LH surge. We have investigated the changes in gonadotropes which ensure that they are responsive to the GnRH surge allowing the release of suf...

Nuclear receptors regulate biological responses by acting as ligand dependent transcription factors in target cells. Their ability to modulate transcription is mediated by cofactors which are recruited to target genes by binding to receptors. They can either act as coactivators or corepressors and their roles include their ability to remodel chromatin and to recruit the basic transcription machinery. NRIP1 is transcriptional repressor which is recruited to nuclear receptors in...

Cyclooxygenase (COX), the rate-limiting enzyme in prostaglandin (PG) biosynthesis exists in two isoforms, COX-1 and COX-2. They are encoded by two separate genes, and show cell-type specific expression and regulation. The expression of COX-1 is constitutive, whereas that of COX-2 is inducible by cytokines/growth factors or inflammatory stimuli. Since the processes of ovulation and implantation are considered analogous to 'proinflammatory' responses, and the involvement of PGs ...