I don't believe that we have a sufficient understanding of neural physiology to provide you with an answer other than puberty.
GnRH
inhibiting the secretion of GnRH
The trigger to begin puberty is GnRH from the hypothalamus.
The endocrine system produces hormones.
GnRH, LH, FSH, inhibin, testosterone (in males), estrogens and progesterone (in females).
GnRH released from the hypothalamus triggers the start of puberty in females.
GnRH-gonadotropin realeasing hormone
Goserelin is an GnRH receptor agonist and bings stronger than GnRH. Due to the constant activation of the GnRH receptor (Goserelin binds really strong; Superagonist) the cell internalizes the receptor -> Downregulation.
Hypophysiotrophic means acting on the hypophysis (pituitary). Usually, factors in the hypothalams such as CRF, GnRH, AVP and etc.. are hypophysiotrophic because stimulate or inhibit secretion of hormones such as ACTH, MSH, LH, FSH, and etc...
No, GnRH or gonadotropin releasing hormone is not a steroid, but rather a peptide (type of protein) hormone.
it is triggered by the smell, taste, sight, or thought of food. parasympathetic impulses trigger gastric juice secretion.
Yes. Corpus luteum sectretes estrogen to inhibit further release of GnRH and secretion of LH and FSH and to prepare and maintain the endometrium for implantation of a fertilized ovum and to prepare mammary glands for milk secretion (this last part explains another influence of protein anabolism stimulation by estrogen).