Related Experiment Video
Updated: Aug 18, 2026

Separation of Follicular Cells and Oocytes in Ovarian Follicles of Zebrafish
Published on: April 18, 2021
Hormonal control of the IGF system in the sea bream ovary
G Gioacchini1, M Cardinali, F Maradonna
1Dipartimento Scienze del Mare, Università Politecnica delle Marche, Ancona, Italy.
Abstract:
Numerous studies have described the presence of an intragonadal IGF system involved in regulation of gametogenesis in teleost fish. In the present study, the in vivo effects of estradiol-17beta (E2) and growth hormone (GH) exposure on IGF-I, IGF-II, IGF1R, and IGFBP2 gene expression in sea bream ovary were monitored by RT-PCR during prereproductive and reproductive periods. The evidence demonstrates that both hormones investigated here affect the ovarian IGF system, showing that it is not only under GH control, but also can be regulated by sexual hormones; this hormonal modulation is related to reproductive phase.
Related Concept Videos
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
Hormonal Regulation
Gonadal and Placental Hormones
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...
Ovarian Cycle
Oogenesis

