Effect of FSH on the growth of follicles and oocytes during culture. (a) Changes in the size of follicles during culture in collagen gel. Follicle size is expressed as follicle diameter relative to the size on day 0 (mean ± SE). The actual size of follicles cultured with FSH is 129.5 ± 2.5 μm and without FSH is 123.9 ± 2.6 μm. Black square show follicles cultured with FSH (n = 21) and white square show follicles cultured without FSH (n = 26). (b) Changes in the size of oocytes during culture. Oocyte size is expressed as oocyte diameter relative to the size on day 0 (mean ± SE). Black square show oocytes cultured with FSH (n = 15) and white square show oocytes cultured without FSH (n = 14). (u), Mann-Whitney U test; (t), t-test; * significance (P < 0.025); NS, not significant.