ATCvet code: QH01CA90.
Pharmacodynamic properties
Buserelin is a peptide hormone which is chemically analogous to the releasing hormone of luteinising hormone (LH) and follicle stimulating hormone (FSH), and therefore is a gonadotrophin releasing hormone (GnRH) analogue.
The mode of action of the veterinary medicinal product corresponds to the physiological action of naturally occurring GnRH. GnRH leaves the hypothalamus via the hypophyseal portal vessels and enters the anterior lobe of the hypophysis where it induces the secretion of the gonadotrophins FSH and LH into the peripheral blood stream. These then act to cause maturation of ovarian follicles, ovulation and luteinisation in the ovary.
Pharmacokinetic properties
After parenteral administration, buserelin is rapidly absorbed and excreted, mainly via the urine. Metabolism takes place in the liver, kidneys and pituitary gland. All metabolites are small, inactive peptides.
Cattle, horses and rabbits:
After buserelin injection, Cmax is reached after one hour. Administration of quantities higher than those clinically recommended do not stimulate increased secretion of LH and FSH. Six hours after administration, plasma concentration of buserelin returns to baseline levels.
Pigs:
After administration of buserelin, Cmax was reached at 1.7 hours.