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Results for “Fecundability”

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PubMed2000

Offsetting effects of Wolbachia infection and heat shock on sperm production in Drosophila simulans: analyses of fecundity, fertility and accessory gland proteins.

Infection in Drosophila simulans with the endocellular symbiont Wolbachia pipientis results in egg lethality caused by failure to properly initiate diploid development (cytoplasmic incompatibility, CI). The relationship between Wolbachia infection and reproductive factors influencing male fitness has not been well examined. Here we compare infected and uninfected strains of D. simulans for (1) sperm production, (2) male fertility, and (3) the transfer and processing of two accessory gland proteins, Acp26Aa or Acp36De. Infected males produced significantly fewer sperm cysts than uninfected males over the first 10 days of adult life, and infected males, under varied mating conditions, had lower fertility compared to uninfected males. This fertility effect was due to neither differences between infected and uninfected males in the transfer and subsequent processing of accessory gland proteins by females nor to the presence of Wolbachia in mature sperm. We found that heat shock, which is known to decrease CI expression, increases sperm production to a greater extent in infected compared to uninfected males, suggesting a possible link between sperm production and heat shock. Given these results, the roles Wolbachia and heat shock play in mediating male gamete production may be important parameters for understanding the dynamics of infection in natural populations.

Animals↗
PubMed2000

Comparison of follicle steroidogenesis from normal and polycystic ovaries in women undergoing IVF: relationship between steroid concentrations, follicle size, oocyte quality and fecundability.

Studies of ovarian stimulation for IVF have suggested a relationship between follicle size and pregnancy rates. Furthermore the follicular endocrine environment is correlated with oocyte quality. The aim of this study was first to verify the relationship between follicular steroid content, follicular size, oocyte maturity and fertilization outcome in women with normal ovaries following recombinant human FSH (rhFSH). Secondly this study was extended to women with polycystic ovarian syndrome (PCOS). Fifty-nine patients (31 normal, 28 PCOS) underwent conventional IVF with rhFSH induction. Follicular diameter was classified as small (8-13 mm) or large (>14 mm) and sex steroid content was analysed for each group. Oocyte maturity was studied according to nuclear maturation the day after fertilization. In both ovulation groups, 17 beta-oestradiol and progesterone concentration were significantly higher in large follicles with meiotically competent oocytes compared with those containing meiotically incompetent oocytes. Testosterone levels were increased in PCOS follicles compared with normal patients, with no difference between corresponding sub-groups of follicles with meiotically competent oocytes. The relationship between follicle size and embryo development showed that 14 mm could be a threshold value following rhFSH induction in normal or PCOS women.

Adult↗