The effect of growth hormone on ovarian follicular response and oocyte nuclear maturation in young and aged mice

SummaryThe aim of this study was to investigate the possible effects of recombinant human growth hormone (rhGH) on the ovarian follicle numbers and the nuclear maturity status of ovulated oocytes. Aged and young Balb-C mice were randomly divided into three groups: (i) control, (ii) stimulated with follicle stimulating hormone (FSH) and (iii) stimulated with FSH+rhGH. Ovaries were collected for histological and morphometric investigations. For the determination of nuclear maturation of ovulated oocytes, additional aged and young mice were randomly divided into two groups: (i) stimulated with FSH and (ii) stimulated with FSH+rhGH. In young mice, developing ovarian follicle numbers were significantly higher with rhGH; while in aged mice, there was no statistically significant difference between groups. In young mice co-stimulated with FSH and rhGH, atretic follicle numbers were significantly higher. In aged mice, atretic follicle numbers significantly decreased with FSH while there was a slight decrease with rhGH and this was not significant. The percentage of metaphase-II oocytes were significantly higher in both young and aged mice groups co-stimulated with FSH and rhGH. In conclusion, co-treatment with FSH and rhGH for ovarian stimulation in older mice appears to cause a slight decrease in the number of atretic follicles and thus improves the collection of high numbers of mature, fertilizable oocytes.