絨毛性ゴナドトロピン (HCG)
生殖ホルモン / ゴナドトロピン
HCGは妊婦の尿から抽出されるポリペプチドホルモンで、主に黄体形成ホルモン（LH）の作用を模倣し、一部卵胞刺激ホルモン（FSH）の活性も持ちます。獣医学では、牛の嚢腫性卵巣、潜在精巣の治療、または性腺機能を評価するHCG試験など、多くの動物種の繁殖障害に広く使用されています。
作用機序: HCG is a glycoprotein that primarily mimics the action of **luteinizing hormone (LH)**, with minor **follicle-stimulating hormone (FSH)**-like activity. * **In Males:** Binds to LH receptors on testicular interstitial (**Leydig**) cells → stimulates differentiation and **androgen (testosterone)** production → promotes testicular descent and spermatogenesis. * **In Females:** Binds to LH receptors on the ovary → stimulates the **corpus luteum** to produce **progesterone** → triggers ovulation of mature follicles. In bitches, it also induces estrogen secretion.
動物種別の用量
Cats
- HCG Challenge test (Male cats or females with suspected sexual differentiation disorder) · 250 micrograms · IM · once · Take sample for resting testosterone level. Administer HCG and take a 4 hour post sample.
- HCG Challenge test (Queens to diagnose functional ovarian tissue) · 50-100 Units · IM · once · Give during apparent estrous episode. Measure progesterone level in 5-7 days. >1 ng/mL indicates functional tissue.
- Infertility, reduced libido, testis descent in male cats · 50-100 Units · IM/SC · repeated if necessary
- Infertility in queens due to confirmed ovulation failure · 100-500 Units · IM · once
- To induce ovulation in anestrus queens · 250 micrograms · IM · once daily for 2 days · 2 days · Give FSH-P 2 mg IM daily until estrus is observed. Give HCG on first and second day of estrus.
- After artificial insemination · 50-75 Units · IM · immediately after insemination; repeat in 24 hours · 24 hours
Ferrets
- Estrus management · 100 Units · IM · repeat in 1 week as necessary · Most effective 14 days after onset of estrus.
Cattle
- Treatment of ovarian cysts · 10,000 Units deep IM or 2500-5000 Units IV. Alternatively, 500-2500 Units injected directly into the follicle. · IM/IV/Intrafollicular · once · May repeat in 14 days if animal's behavior or physical exam indicates a need for retreatment.
Horses
- Cryptorchidism (Foals) · 1000 Units · IM/SC · twice weekly · 4-6 weeks · Note: Many clinicians believe that medical treatment is unwarranted and that surgery should be performed.
- To induce ovulation in early estrus (dominant follicle >35 mm) · 2000-3000 Units · IV · once · Preferable to treat mare 6 hours before mating.
- Treatment of persistent follicles during the early transition period · 1000-5000 Units · IM/IV · once · Results are variable.
- To hasten ovulation and reduce variability of estrus after prostaglandin synchronization · 1500-3300 Units · IM/IV · once · Give 5-6 days after the second prostaglandin treatment or on the first or second day of estrus.
Birds
- To reduce feather plucking (especially in female birds) · 500-1,000 Units/kg · IM · once · Dosage is empirical. If no response in 3 days, repeat. If reduces feather plucking, will need to repeat after 4-6 weeks. Repeated usage reduces time between treatments.
SmallMammals
- Cystic ovaries (Guinea pigs) · 1000 Units/animal · IM · repeat in 7-10 days
Dogs
- Cryptorchidism · 500 Units injected twice weekly · IM/SC · twice weekly · 4-6 weeks
- HCG Challenge test (Male dogs or females with suspected sexual differentiation disorder) · 44 micrograms/kg · IM · once · Take sample for resting testosterone level. Administer HCG and take a 4 hour post sample.
- HCG Challenge test (Female dogs to diagnose functional ovarian tissue) · 100-1000 Units · IM · once · Give during apparent estrous episode. Measure progesterone level in 5-7 days. >1 ng/mL indicates functional tissue.
- To produce luteinization of a persistent follicular cyst · 500 Units · IM · repeat in 48 hours · If effective, will convert from proestrus to estrus in 1-2 days and sexual behavior should stop within 2 weeks.
- Infertile bitches cycling normally with low progesterone due to lack of corpus luteum formation · 500 Units · SC · once · Give on days 10-11 of heat cycle or when vaginal smear indicates breeding readiness. Breed 2 days after administration.
- Male infertility secondary to low testosterone, LH and FSH · 500 Units · SC · twice weekly · 4 weeks · Add PMSG 20 Units/kg SC 3 times weekly. Continue for 3 months. Once spermatogenesis ensues, may continue with HCG only.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
IMIVSCIntrafollicular
禁忌
- Androgen-dependent neoplasias (e.g., prostatic carcinoma)
- Precocious puberty
- Known hypersensitivity to HCG
- Pregnancy (FDA Category X in humans, unless specifically indicated for reproductive management)
有害事象
- Hypersensitivity reactions / Anaphylaxis
- Pain at the injection site
- Antibody production leading to diminished efficacy (with repeated use)
- Abortion in mares if given prior to the 35th day of pregnancy
- Gynecomastia, headache, depression, irritability, and edema (reported in humans)
モニタリング
- Testosterone levels (for HCG challenge test in males)
- Progesterone levels (for HCG challenge test in females)
- Resolution of clinical signs (e.g., cessation of estrus behavior, resolution of cystic ovaries)
- Signs of hypersensitivity or anaphylaxis post-injection
過量投与
No overdosage cases have been reported with HCG in veterinary medicine.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。