>>13732098https://www.frontiersin.org/articles/10.3389/fendo.2013.00180/full"Molecular phylogeny of GnRH ligands shows that there are three distinct forms, GnRH-I, GnRH-II, and GnRH-III that arose from a common origin which predates vertebrates (10). Most vertebrate classes have GnRH-I and GnRH-II (1, 3, 11), whereas GnRH-III has only been found in teleosts (12–23). Interestingly, the GnRH-I sequence has diverged in the vertebrate lineage, whereas the sequences of GnRH-II and GnRH-III are completely conserved across vertebrates" I'm not reading all this paper because it's too long and I'm not a fucking molecular biologist
https://www.yourhormones.info/hormones/gonadotrophin-releasing-hormone/"During childhood, the levels of gonadotrophin-releasing hormone are extremely low, but as puberty approaches there is an increase in gonadotrophin-releasing hormone, which triggers the onset of sexual maturation.
When the ovaries and testes are fully functional, the production of gonadotrophin-releasing hormone, luteinising hormone and follicle stimulating hormone are controlled by the levels of testosterone (in men) and oestrogens (e.g. oestradiol) and progesterone (in women). If the levels of these hormones rise, the production of gonadotrophin-releasing hormone decreases and vice versa.
There is one exception to this rule; in women, at the midpoint of their menstrual cycle, oestradiol (produced by the follicle in the ovary that contains the dominant egg) reaches a critical high point. This stimulates a large increase in gonadotrophin-releasing hormone secretion and, consequently, a surge of luteinising hormone, which stimulates the release of a mature egg. This process is called ovulation."
