Nitschelm D, van der Horst C J
Tijdschr Diergeneeskd. 1977 Jul 15;102(14):805-16.
The effect of orally administered chlormadinone acetate (CAP), 10 mg daily for a period of 16 days, was investigated in the case of four mares with an irregular oestrous pattern accompanied by low ovarian activity (group 1), four mares which did not show oestrous symptoms at all and which had also low ovarian activity (group 2), and two ovariectomized and two ovario-hysterectomized mares (group 3). In all mares of group 1 and in the two ovariectomized mares of group 3 oestrus symptoms became apparent during treatment. Two mares of group 2 came into heat 8 and 11 days after the cessation of treatment. The two other mares of group 2 and the ovario-hysterectomized mares of group 3 showed no oestrous symptoms at all. In all except the two ovario-hysterectomized mares the progesterone concentration was found to increase in the peripheral blood from less than 1 ng/ml up to at least 4-6 ng/ml. In the mares which came into oestrus this progesterone increase occurred about three days before symptoms of heat became apparent. It is assumed that the uterus played an important role in the increase of the progesterone concentration in the blood during or after CAP treatment. A similar rise of the progesterone level was also found in the ovariectomized mares, indicating that this progesterone did not originate in the ovaries.
对四匹发情周期不规律且卵巢活性较低的母马（第1组）、四匹完全不表现发情症状且卵巢活性也较低的母马（第2组）以及两匹卵巢切除和两匹卵巢子宫切除的母马（第3组），研究了口服醋酸氯地孕酮（CAP）（每日10毫克，持续16天）的效果。在治疗期间，第1组所有母马以及第3组两匹卵巢切除的母马出现了发情症状。第2组的两匹母马在停止治疗后8天和11天发情。第2组的另外两匹母马以及第3组卵巢子宫切除的母马完全没有表现出发情症状。除了两匹卵巢子宫切除的母马外，在所有母马中都发现外周血中孕酮浓度从低于1纳克/毫升增加到至少4 - 6纳克/毫升。在发情的母马中，这种孕酮增加发生在发情症状明显出现前约三天。据推测，子宫在CAP治疗期间或之后血液中孕酮浓度的增加中起重要作用。在卵巢切除的母马中也发现了类似的孕酮水平升高，表明这种孕酮并非来自卵巢。
