Bravo P W, Stabenfeldt G H, Lasley B L, Fowler M E
Department of Reproduction, School of Veterinary Medicine, University of California, Davis 95616.
Biol Reprod. 1991 Oct;45(4):553-9. doi: 10.1095/biolreprod45.4.553.
The relation of ovarian follicle size to pituitary and ovarian responses to copulation was studied in domesticated South American camelids (llamas and alpacas). Females from each species were divided into four groups according to follicle size: small (4-5 mm), growing (6-7 mm), mature (8-12 mm), and regressing (10-7 mm). The pituitary response to copulation was determined by analysis of LH and FSH concentrations in plasma. The ovarian response to copulation was determined by ultrasonography and by analysis of estrone sulfate (follicular status) and pregnanediol glucuronide (luteal status) concentrations in urine. Females with small follicles (4-5 mm) released less LH after copulation than did those with larger follicles, and ovulation was not induced. Females with growing and mature follicles (7-12 mm) released LH in response to copulation that was adequate to induce ovulation and to initiate normal luteal activity. While copulation-induced LH release in females with regressing follicles was similar to that released in animals with growing and mature follicles, regressing follicles were luteinized instead of being ovulated. The luteal structure formed as a result of luteinization of follicles had a short life span, i.e., 5.1 days. Copulation-induced LH release was significantly higher in llamas vs. alpacas in animals with mature or regressing follicles, but not in those with small or growing follicles. Urinary estrone sulfate and pregnanediol glucuronide concentrations correlated positively with the presence of follicles and corpora lutea, respectively.
在驯化的南美骆驼科动物（美洲驼和羊驼）中，研究了卵巢卵泡大小与垂体及卵巢对交配反应之间的关系。每个物种的雌性根据卵泡大小分为四组：小卵泡（4 - 5毫米）、生长卵泡（6 - 7毫米）、成熟卵泡（8 - 12毫米）和退化卵泡（10 - 7毫米）。通过分析血浆中促黄体生成素（LH）和促卵泡生成素（FSH）的浓度来确定垂体对交配的反应。通过超声检查以及分析尿液中硫酸雌酮（卵泡状态）和孕二醇葡糖苷酸（黄体状态）的浓度来确定卵巢对交配的反应。小卵泡（4 - 5毫米）的雌性在交配后释放的LH比卵泡较大的雌性少，且未诱导排卵。生长卵泡和成熟卵泡（7 - 12毫米）的雌性在交配后释放的LH足以诱导排卵并启动正常的黄体活动。虽然退化卵泡的雌性中交配诱导的LH释放与生长卵泡和成熟卵泡的动物相似，但退化卵泡会发生黄素化而非排卵。卵泡黄素化形成的黄体结构寿命较短，即5.1天。在成熟或退化卵泡的动物中，美洲驼交配诱导的LH释放显著高于羊驼，但在小卵泡或生长卵泡的动物中并非如此。尿液中硫酸雌酮和孕二醇葡糖苷酸的浓度分别与卵泡和黄体的存在呈正相关。
