Endocrinological studies on TAP-144-SR, a sustained-release formulation of a potent GnRH agonist (D-Leu6-[des-Gly10-NH2]-GnRH ethylamide), in male rats. 1990

K Sudo, and T Masaki, and K Shiota, and M Kawase, and T Fujita
Research and Development Division, Takeda Chemical Industries, Ltd. Osaka, Japan.

The paradoxical effects of TAP-144-SR, a biodegradable sustained-release formulation of a potent GnRH agonist (TAP-144, leuprolide acetate) were evaluated in male rats by comparing its potency with that of TAP-144 solution. A single sc injection of TAP-144-SR (equivalent to 0.1 mg/kg/day as TAP-144), prepared by encapsulating the agonist in microcapsules of copoly (DL-lactic/glycolic acid), suppressed serum levels of androgens, and the levels remained suppressed for 4 weeks. The potency of the paradoxical effects of TAP-144-SR was evaluated 4 weeks after treatment by comparing it with that of TAP-144 solution administered daily for 4 weeks. Both daily injections of TAP-144 solution and a single injection of TAP-144-SR (equivalent to 0.02, 0.2 or 2 mg/kg/day as TAP-144) decreased the weight of the testes, prostates and seminal vesicles in a dose-dependent manner in a 4-week assay in male rats. TAP-144-SR was more effective than TAP-144 solution in reducing these organ weights. Serum and pituitary concentrations of LH and FSH and serum testosterone levels were also lower in TAP-144-SR-treated than in TAP-144 solution-treated rats. These results indicate that the paradoxical effects were more extensive upon TAP-144-SR treatment, suggesting that maintaining constant serum TAP-144 levels results in more extensive desensitization of the pituitary and testes. These results also suggest advantages of TAP-144-SR over TAP-144 solution in both efficacy and convenience as an anti-prostatic tumor agent.

UI MeSH Term Description Entries
D007279 Injections, Subcutaneous Forceful administration under the skin of liquid medication, nutrient, or other fluid through a hollow needle piercing the skin. Subcutaneous Injections,Injection, Subcutaneous,Subcutaneous Injection
D007986 Luteinizing Hormone A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity. ICSH (Interstitial Cell Stimulating Hormone),Interstitial Cell-Stimulating Hormone,LH (Luteinizing Hormone),Lutropin,Luteoziman,Luteozyman,Hormone, Interstitial Cell-Stimulating,Hormone, Luteinizing,Interstitial Cell Stimulating Hormone
D007987 Gonadotropin-Releasing Hormone A decapeptide that stimulates the synthesis and secretion of both pituitary gonadotropins, LUTEINIZING HORMONE and FOLLICLE STIMULATING HORMONE. GnRH is produced by neurons in the septum PREOPTIC AREA of the HYPOTHALAMUS and released into the pituitary portal blood, leading to stimulation of GONADOTROPHS in the ANTERIOR PITUITARY GLAND. FSH-Releasing Hormone,GnRH,Gonadoliberin,Gonadorelin,LH-FSH Releasing Hormone,LHRH,Luliberin,Luteinizing Hormone-Releasing Hormone,Cystorelin,Dirigestran,Factrel,Gn-RH,Gonadorelin Acetate,Gonadorelin Hydrochloride,Kryptocur,LFRH,LH-RH,LH-Releasing Hormone,LHFSH Releasing Hormone,LHFSHRH,FSH Releasing Hormone,Gonadotropin Releasing Hormone,LH FSH Releasing Hormone,LH Releasing Hormone,Luteinizing Hormone Releasing Hormone,Releasing Hormone, LHFSH
D008297 Male Males
D009929 Organ Size The measurement of an organ in volume, mass, or heaviness. Organ Volume,Organ Weight,Size, Organ,Weight, Organ
D010902 Pituitary Gland A small, unpaired gland situated in the SELLA TURCICA. It is connected to the HYPOTHALAMUS by a short stalk which is called the INFUNDIBULUM. Hypophysis,Hypothalamus, Infundibular,Infundibular Stalk,Infundibular Stem,Infundibulum (Hypophysis),Infundibulum, Hypophyseal,Pituitary Stalk,Hypophyseal Infundibulum,Hypophyseal Stalk,Hypophysis Cerebri,Infundibulum,Cerebri, Hypophysis,Cerebrus, Hypophysis,Gland, Pituitary,Glands, Pituitary,Hypophyseal Stalks,Hypophyses,Hypophysis Cerebrus,Infundibular Hypothalamus,Infundibular Stalks,Infundibulums,Pituitary Glands,Pituitary Stalks,Stalk, Hypophyseal,Stalk, Infundibular,Stalks, Hypophyseal,Stalks, Infundibular
D011467 Prostate A gland in males that surrounds the neck of the URINARY BLADDER and the URETHRA. It secretes a substance that liquefies coagulated semen. It is situated in the pelvic cavity behind the lower part of the PUBIC SYMPHYSIS, above the deep layer of the triangular ligament, and rests upon the RECTUM. Prostates
D011863 Radioimmunoassay Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation. Radioimmunoassays
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D003692 Delayed-Action Preparations Dosage forms of a drug that act over a period of time by controlled-release processes or technology. Controlled Release Formulation,Controlled-Release Formulation,Controlled-Release Preparation,Delayed-Action Preparation,Depot Preparation,Depot Preparations,Extended Release Formulation,Extended Release Preparation,Prolonged-Action Preparation,Prolonged-Action Preparations,Sustained Release Formulation,Sustained-Release Preparation,Sustained-Release Preparations,Timed-Release Preparation,Timed-Release Preparations,Controlled-Release Formulations,Controlled-Release Preparations,Extended Release Formulations,Extended Release Preparations,Slow Release Formulation,Sustained Release Formulations,Controlled Release Formulations,Controlled Release Preparation,Controlled Release Preparations,Delayed Action Preparation,Delayed Action Preparations,Formulation, Controlled Release,Formulations, Controlled Release,Prolonged Action Preparation,Release Formulation, Controlled,Release Formulations, Controlled,Sustained Release Preparation,Timed Release Preparation,Timed Release Preparations

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