Onset and Heterogeneity of Responsiveness to FSH in Mouse Preantral Follicles in Culture

Abstract

The obligatory role of follicle-stimulating hormone (FSH) in normal development and function of ovarian antral follicles is well recognized, but its function in preantral growth is less clear. The specific objective of this study was to investigate the response, in culture, to FSH of mouse preantral follicles of increasing size, focusing particularly on growth rate and gene expression. Preantral follicles were mechanically isolated from ovaries of C57BL/6 mice, 12 to 16 days postpartum, and single follicles cultured for up to 96 hours in medium alone (n = 511) or with recombinant human FSH 10 ng/mL (n = 546). Data were grouped according to initial follicle diameter in 6 strata ranging from <100 to >140 μm. Follicles of all sizes grew in the absence of FSH (P < 0.01, paired t test). All follicles grew at a faster rate (P < 0.0001) in the presence of 10 ng/mL FSH but larger follicles showed the greatest change in response to FSH. Even the smallest follicles expressed FSH receptor messenger RNA (mRNA). FSH-induced growth was inhibited by KT5720, an inhibitor of protein kinase A (PKA), implicating the PKA pathway in FSH-induced follicle growth. In response to FSH in vitro, FSH receptor mRNA (measured by quantitative polymerase chain reaction) was reduced (P < 0.01), as was Amh (P < 0.01), whereas expression of StAR (P < 0.0001) and the steroidogenic enzymes Cyp11a1 (P < 0.01) and Cyp19 (P < 0.0001) was increased. These results show heterogeneous responses to FSH according to initial follicle size, smaller follicles being less FSH dependent than larger preantral follicles. These findings strongly suggest that FSH has a physiological role in preantral follicle growth and function.

A novel action of follicle-stimulating hormone in the ovary promotes estradiol production without inducing excessive follicular growth before puberty

“…In the present report, we bring experimental evidence that despite its tremendous increase, FSH does not drive the sequence of events required to achieve these processes, that is follicular growth where granulosa cells proliferate and the antral cavity develops, and then follicular maturation wherein mural granulosa cells become LH-responsive and activate EGFR signaling to trigger ovulation. Our study does not question the fact that FSH is required for basal follicular growth up to the preantral/early antral stage during the infantile period, as shown previously17181920. But it supports the idea that elevated concentrations of FSH are unable to support subsequent growth of those follicles.…”

Effects of Vitamin E Supplementation on Serum Hormones and Gene Expression of Anti-Season Breeding Xingguo Grey Geese (Anser Cygnoides)

“…FSH mainly regulated follicular development and selection. The literature on Hardy et al proved that FSH was essential for pre-antral follicle growth and function in mice (Hardy et al, 2017). In poultry, FSH treatment increased the embryonic chicken ovarian germ cell number, granulosa cells number and reduced cell apoptosis in different stage of follicles (Lin et al, 2011).…”

Stimulation of nicotinic receptors in the suprachiasmatic nucleus results in a higher number of growing follicles and ova shed

“…According to Baba, Ting, Tkachenko, Xu, and Stouffer (), follicle stimulating hormone (FSH) plays a key role in the regulation of developing follicles, the stimulation of their growth, the initiation of the secretion of oestradiol and the differentiation of the antral follicle, since the depletion of FSH results in the arrest of follicle growth in the preantral to early antral stages (Hardy et al., ). Domínguez‐González et al.…”