trelstar and Testicular-Neoplasms

The availability of GnRH agonist implants offers the possibility of a reversible, temporary downregulation of endocrine and germinative testicular function in male dogs and hobs. This review provides an overview of the registered indication, the induction of temporary infertility in healthy, intact, sexually mature male dogs (4.7 and 9.4 mg deslorelin) and hobs (9.4 mg deslorelin) as well as various off-label indications. Off-label use requires strict indications, informed consent from the owner and a lack of licensed medication (safe and optimum effect). Off-label indications in the male dog include sexual-hormone dependant (disturbing) behavior, benign prostatic hyperplasia, small adenomas of the hepatoid glands and alopecia X. Successful use of deslorelin implants for estrus suppression in jils, but also for the treatment of hyperadrenocorticism in ferrets in general have been described. Similarly, hormonal castration can be induced in tomcats and queens. The variable time to onset of effect and its duration (extremely variable in some animals) represent a challenge for breeders. No (sufficient) contraceptive activity was identified in male rabbits and male guinea pigs; however, treatment did successfully suppress the estrus cycle in female individuals of these species, as well as reproductive activity in male and female rats. Regarding the use in birds and reptiles, significant species-specific differences exist with regard to efficacy, time until onset of effect and duration of downregulation. In birds, the implant is efficient to fully suppress egg laying in chicken, Japanese quail and psittacids. In doves, egg laying is only significantly reduced. Successful treatment of reproduction-associated (unwanted) behaviour patterns (feather picking, aggression) has also been described. In some male birds, namely zebrafinch and Japanese quail, the deslorelin implant is suitable to reduce testosterone levels. Successful treatment of hormone-dependent tumours (Sertoli-cell tumorus) in budgerigars has been described as well as the modulation of specific behavior in turkeys and an efficacy in facilitating their keeping (i. e. reduction of aggression). In reptiles, only the successful use of deslorelin in iguana has been demonstrated to date.. Die Verfügbarkeit von GnRH-Agonist-Implantaten bietet die Möglichkeit der reversiblen, temporären Downregulation der endokrinen und germinativen Hodenfunktion bei Rüden und Frettchenrüden. Diese Übersichtsarbeit liefert einen Überblick über die zugelassene Indikation, Erzielung einer vorübergehenden Unfruchtbarkeit bei gesunden, unkastrierten, geschlechtsreifen Rüden (4,7 und 9,4 mg Deslorelin) und Frettchenrüden (9,4 mg Deslorelin) sowie über verschiedene Off-Label-Indikationen. Die Off-Label-Anwendung erfordert eine strenge Indikationsstellung, Besitzeraufklärung und einen Therapienotstand. Off-Label-Indikationen beim Rüden sind sexualhormonabhängiges (störendes) Verhalten, benigne Prostatahyperplasie, Adenome der perinealen Drüsen und Alopezie X. Die Anwendung erfolgt beim Frettchen zur Unterdrückung der Fertilität und des Zyklus, aber auch zur medikamentösen Therapie des Hyperadrenokortizismus. Bei Katze und Kater kann ebenso eine Unterdrückung der Fortpflanzung induziert werden. Problematisch sind hier insbesondere der variable Wirkeintritt und die unterschiedliche, z. T. sehr lange Wirkdauer. Während kein (ausreichend) kontrazeptiver Effekt bei männlichen Kaninchen und Meerschweinchen nachgewiesen wurde, kann das Implantat den Zyklus bei weiblichen Kaninchen und Meerschweinchen sowie die Reproduktion bei Ratten beiderlei Geschlechts unterdrücken. Bei Vögeln und Reptilien bestehen signifikante speziespezifische Unterschiede hinsichtlich Wirksamkeit, Wirkeintritt und Wirkdauer. Ein erfolgreicher Einsatz ist bei Huhn, Japanwachtel und Psittaziden hinsichtlich Verhinderung der Eiablage beschrieben, bei Tauben kommt es nur zur Reduktion der Eiablage. Berichte zum erfolgreichen Einsatz bei reproduktionsassoziierten Verhaltensproblemen (Federpicken, Aggressivität) liegen ebenfalls vor. Bei männlichen Tieren einzelner Vogelspezies (Japanwachtel, Zebrafink) bewirkt das Deslorelin-Implantat eine Reduktion der Testosteronkonzentration. Therapeutisch ist der erfolgreiche Einsatz beim Wellensittich mit hormonproduzierendem Sertoli-Zell-Tumor sowie beim Truthahn zur Verhaltensmodulation und Haltungserleichterung (Reduktion der Aggression) beschrieben. Bei Leguanen unterdrückt das Implantat die Ovaraktivität.

Topics: Animals; Antineoplastic Agents, Hormonal; Bird Diseases; Birds; Contraception; Dog Diseases; Dogs; Drug Implants; Ferrets; Gonadotropin-Releasing Hormone; Male; Testicular Neoplasms; Triptorelin Pamoate; Veterinary Drugs

Possible protective effects of D-Tryptophan-6 luteinizing hormone releasing hormone (D-Trp-6-LH-RH) against irradiation-induced testicular damage were investigated for the first time in patients with seminoma. After unilateral orchiectomy 12 men were allocated to receive the long-acting gonadotropin releasing hormone (GnRH) agonist D-Trp-6-LH-RH prior to and for the duration of radiotherapy. Eight patients with the same disease served as a control group. In contrast to several trials to protect spermatogenesis from chemotherapy by GnRH agonists, we first suppressed the pituitary-testicular axis before starting the treatment. As a new schedule this adjuvant GnRH agonist treatment was combined with cyproterone acetate for the first 20 days to diminish the amount and the duration of the initial stimulation of gonadotropins and testosterone. Irradiation started after suppression of the pituitary-gonadal axis. In all patients luteinizing hormone and testosterone were completely suppressed throughout the treatment compared to the controls, whereas the initial suppression of follicle-stimulating hormone was not completely maintained until radiotherapy was completed. At the follow-up at 18 months after completion of therapy, all patients reached their initial concentration of gonadotropins, testosterone, and motile spermatozoa independently of D-Trp-6-LH-RH treatment. With the dose and schedule investigated, the GnRH agonist showed no protective effects against testicular damage caused by radiotherapy.

Topics: Adult; Follow-Up Studies; Humans; Male; Radiation-Protective Agents; Seminoma; Spermatogenesis; Testicular Neoplasms; Triptorelin Pamoate

Topics: Adult; Age Determination by Skeleton; Child; Child, Preschool; Father-Child Relations; Gels; Hormone Replacement Therapy; Humans; Male; Orchiectomy; Puberty, Precocious; Seminoma; Skin Absorption; Testicular Neoplasms; Testosterone; Touch; Triptorelin Pamoate

Topics: Antineoplastic Agents; Gonadotropin-Releasing Hormone; Humans; Male; Prostatic Neoplasms; Testicular Neoplasms; Triptorelin Pamoate

The purposes of our study concerning two patients with oestrogen secreting Leydig cell tumour were to determine whether endogenous LH levels are involved in testicular tumour steroidogenesis and whether aromatase activity of oestrogen secreting Leydig cell tumours is directly or indirectly dependent on LH levels.. E2 and T were evaluated after hCG injection (5000 IU) during 96 hours. Bio and immuno LH, T, E2, were determined at the basal state and after administration of D-Trp-6-GnRH agonist (3.75 mg) every 3 weeks. The abnormal testis was removed after the third injection and testicular venous blood was collected during the operation. Testicular tumour was incubated with 4-14C-T.. Oestradiol (E2) response to hCG injection (5000 IU) was prolonged and exaggerated while that of testosterone (T) was similar to that of the controls. The aromatase index (E2/T) remained elevated even 96 hours after hCG. Intramuscular injection of the GnRH agonist, D-Trp-6-GnRH (3.75 mg) resulted in a reduction of immunoreactive and bioactive LH. T was decreased to about 10% of baseline levels and E2 fell from 240 to 36 pmol/l. In the blood of the spermatic veins collected in the course of surgery, E2 levels were found to be lower in comparison with the controls. E2 was found to be twofold higher in the spermatic vein draining the tumoral side than in that of the contralateral testis. Incubation of the testicular tumours with 4-14C-T, displayed a reduced aromatase activity (conversion of T to E2: 0.3 and 0.1% in patients 1 and 2 respectively).. The kinetics of E2 response to hCG administration would suggest a modification of the regulation of the aromatase activity in this type of oestrogen secreting tumour. A certain endogenous LH level may be necessary to supply a sufficient quantity of T substrate, and to maintain aromatase activity of such Leydig cell tumours secreting oestrogens. These tumours seem to be responsive to endogenous LH levels.

Topics: Adult; Antineoplastic Agents; Aromatase; Chorionic Gonadotropin; Estradiol; Estrogens; Humans; Leydig Cell Tumor; Luteinizing Hormone; Male; Testicular Neoplasms; Testis; Testosterone; Triptorelin Pamoate