Smith M S, McLean B K, Neill J D
Endocrinology. 1976 Jun;98(6):1370-7. doi: 10.1210/endo-98-6-1370.
The luteotropic stimuli necessary to transform the corpus luteum of the estrous cycle into a corpus luteum of psuedopregnancy on the morning of diestrus-2 (Day 2), as reflected by a dramatic divergence in progesterone secretion, were studied (Day 1 was taken as the first day of diestrus of pseudopregnancy). The requirement of prolactin (PRL) as a luteotropic stimulus was determined by inhibiting the diurnal and nocturnal PRL surges that occur immediately before and during the divergence in progesterone. Following cervical stimulation, 1 mg of 2-Br-alpha-ergocryptine (EC) was injected at 1100 and 2300 h on Day 1 (lights on 0600-1800 h), and the animals were decapitated at 2-4 h intervals from 1100 h on Day 1 to 1700 h on Day 2. In the control animals, the PRL surges on Day 1 and Day 2 were associated with an increase in progesterone secretion on Day 2. However, the regimen of EC treatment resulted in an inhibition of PRL surges, prolactin remaining at baseline values from 1100 h on Day 1 to 1700 h on Day 2. The inhibition of PRL secretion was associated with a fall in progesterone concentration to reach baseline values by 1700h on Day 2. Furthermore, a group of animals similarly treated with EC returned to vaginal estrus 2 days later. LH concentrations did not differ in control and EC-treated animals. The effect of EC on corpus luteum function could be completely reversed by the simultaneous administration of PRL. In addition, if PRL was administered at 1100 h and 2300 h on diestrus-1 of the estrous cycle, in an attempt to mimic the surges os pseudopregnancy, regression of the corpora lutea did not occur. Progesterone levels increased to reach values comparable to those observed in pseudopregnancy on diestrus-2. The role of LH was studied by administering a dose of LH antiserum at 110 and 2300 h on Day 1 of pseudopregnancy. This treatment failed to inhibit the increase in progesterone observed on Day 2. These results demonstrate that the surges of plasma PRL initiated by cervical stimulation are responsible for transforming a corpus luteum of the estrous cycle into a corpus luteum of pseudopregnancy, as reflected by an increase in progesterone secretion of Day 2. LH seems to have a minor role in maintaining corpus luteum function beyond that observed during the estrous cycle.
研究了在动情后期-2（第2天）早晨将发情周期的黄体转化为假孕黄体所需的促黄体刺激，这可通过孕酮分泌的显著差异反映出来（第1天被视为假孕动情后期的第一天）。通过抑制在孕酮分泌差异之前及期间立即出现的昼夜催乳素（PRL）激增，确定了PRL作为促黄体刺激的必要性。在宫颈刺激后，于第1天的1100和2300时（光照时间为0600 - 1800时）注射1毫克2 - 溴-α-麦角隐亭（EC），并在从第1天的1100时到第2天的1700时每隔2 - 4小时将动物断头。在对照动物中，第1天和第2天的PRL激增与第2天孕酮分泌增加相关。然而，EC处理方案导致PRL激增受到抑制，从第1天的1100时到第2天的1700时催乳素维持在基线值。PRL分泌的抑制与孕酮浓度下降相关，到第2天的1700时降至基线值。此外，一组用EC同样处理的动物在2天后恢复到阴道发情期。对照动物和经EC处理的动物的促黄体生成素（LH）浓度没有差异。同时给予PRL可完全逆转EC对黄体功能的影响。此外，如果在发情周期的动情后期-1的1100和2300时给予PRL，试图模拟假孕的激增，则黄体不会发生退化。孕酮水平升高，达到与在动情后期-2假孕中观察到的值相当的水平。通过在假孕第1天的110和2300时给予一剂LH抗血清来研究LH的作用。这种处理未能抑制在第2天观察到的孕酮增加。这些结果表明，由宫颈刺激引发的血浆PRL激增负责将发情周期的黄体转化为假孕黄体，这可通过第2天孕酮分泌增加反映出来。LH在维持黄体功能方面似乎比在发情周期中观察到的作用小。
