indication

For evaluating the functional capacity and response of the gonadotropes of the anterior pituitary also for evaluating residual gonadotropic function of the pituitary following removal of a pituitary tumor by surgery and/or irradiation.

pharmacology

Gonadorelin is responsible for the release of follicle stimulating hormone and leutinizing hormone from the anterior pitutitary. In the pituitary GnRH stimulates synthesis and release of FSH and LH, a process that is controlled by the frequency and amplitude of GnRH pulses, as well as the feedback of androgens and estrogens. The pulsatility of GnRH secretion has been seen in all vertebrates, and it is necessary to ensure a correct reproductive function. Thus a single hormone, GnRH, controls a complex process of follicular growth, ovulation, and corpus luteum maintenance in the female, and spermatogenesis in the male. Its short half life requires infusion pumps for its clinical use

mechanism of action

Systemic - Like naturally occurring gonadotropin-releasing hormone (GnRH), gonadorelin primarily stimulates the synthesis and release of luteinizing hormone (LH) from the anterior pituitary gland. Follicle-stimulating hormone (FSH) production and release is also increased by gonadorelin, but to a lesser degree. In prepubertal females and some gonadal function disorders, the FSH response may be greater than the LH response. For the treatment of amenorrhea, delayed puberty, and infertility the administration of gonadorelin is used to simulate the physiologic release of GnRH from the hypothalamus in treatment of delayed puberty, treatment of infertility caused by hypogonadotropic hypogonadism, and induction of ovulation in those women with hypothalamic amenorrhea. This results in increased levels of pituitary gonadotropins LH and FSH, which subsequently stimulate the gonads to produce reproductive steroids.

toxicity

LD₅₀>3000 mg/kg (rat, oral)

biotransformation

Rapidly hydrolyzed to inactive peptide components

absorption

Rapidly absorbed when injected

half life

Very short, initial, 2 to 10 minutes; terminal, 10 to 40 minutes