Use of a new drug delivery formulation of the gonadotrophin-releasing hormone analogue Deslorelin for reversible long-term contraception in male dogs

Abstract

In the present study, we tested the effect of treatment with a slow-release implant containing the gonadotrophin-releasing hormone agonist Deslorelin(TM) (Peptech Animal Health Australia, North Ryde, NSW, Australia) on pituitary and testicular function in mature male dogs. Four dogs were treated with Deslorelin (6-mg implant) and four were used as controls (blank implant). In control dogs, there were no significant changes over the 12 months of the study in plasma concentrations of luteinising hormone (LH) or testosterone, or in testicular volume, semen output or semen quality. In Deslorelin-treated dogs, plasma concentrations of LH and testosterone were undetectable after 21 and 27 days, testicular volume fell to 35% of pretreatment values after 14 weeks and no ejaculates could be obtained after 6 weeks. Concentrations returned to the detectable range for testosterone after 44 weeks and for LH after 51 weeks and both were within the normal range after 52 weeks. Semen characteristics had recovered completely by 60 weeks after implantation. At this time, the testes and prostate glands were similar histologically to those of control dogs. We conclude that a single slow-release implant containing 6 mg Deslorelin has potential as a long-term, reversible antifertility agent for male dogs.

The effect of deslorelin acetate on the oestrous cycle of female guinea pigs

“…Deslorelin acetate is a long-acting synthetic GnRH agonist used for the control of sexual behaviour in various animal species (McRae et al 1985;Munson et al 2001;Junaidi et al 2003;Schoemaker et al 2008;Romagnoli et al 2009;Fontaine et al Original Paper Veterinarni Medicina, 60, 2015 (3): 155-160 (Munson et al 2001;Junaidi et al 2003;Schoemaker et al 2008;Romagnoli et al 2009). However, there is insufficient knowledge of the effect of deslorelin in guinea pigs to allow its safe use in practice.…”

Fertility control in a male rabbit using a deslorelin implant. A case report

“…Because semen parameters were not assessed, the effect of the deslorelin implant on fertility cannot be evaluated, but it is likely that the observed suppression of testosterone and decrease in testes size corresponded to a discontinued spermatogenesis. This effect of deslorelin implants has been demonstrated in dogs (Junaidi et al, 2003), kangaroos (Herbert et al, 2004), and other species. The co-housing with a fertile female rabbit did not result in undesired offspring.…”

“…Regarding the subsequent increase in testosterone and re-growth of the testes, it can be presumed that semen characteristics had recovered completely. The complete recovery of male fertility has been demonstrated in dogs (Junaidi et al, 2003;Trigg et al, 2006 Surgical castration reduces testosterone-dependent aggression among males (Arteaga et al, 2008), reduces the size and secretory activity of the chin gland, and reduces or eliminates territory marking (Girolami et al, 1997). Hence, it seems that these conditions might also be influenced by administration of a deslorelin implant, with a consequent decline in serum testosterone concentrations.…”

“…Recently, slow-release biocompatible implants containing deslorelin have provided an opportunity for effective contraception for male dogs (Junaidi et al, 2003), mice (Kher and Kalla, 1996), ferrets (Schoemaker et al, 2008), koalas (Herbert et al, 2001), Tammar wallabies (Herbert et al, 2004) and other species. As yet, no adverse effects have been reported (Trigg et al, 2006).…”

Long-term effects of deslorelin implants on reproduction in the female tammar wallaby (Macropus eugenii)

“…Treatment with the GnRH agonist deslorelin can inhibit reproduction for periods of $ 1 year in a range of eutherian species, including dogs , Junaidi et al 2003, cats (Munson et al 2001) and heifers (D'Occhio et al , 2002. GnRH agonist-induced suppression of ovarian cycles is typically characterised by an inhibition of follicular development and a reduction in plasma oestradiol, progesterone and follicle-stimulating hormone (FSH) concentrations.…”