Rosenblatt J S, Olufowobi A, Siegel H I
Psychology Department, Rutgers University, Newark, New Jersey 07102, USA.
Horm Behav. 1998 Apr;33(2):104-14. doi: 10.1006/hbeh.1998.1441.
The aim of the study was to determine whether there is an increase in responsiveness to estrogen stimulation of maternal behavior and lordosis responsiveness during pregnancy. Using separate groups of pregnancy-terminated females, we measured the initial maternal responsiveness of hysterectomized-ovariectomized (HO) females and their responsiveness to estrogen stimulation. Maternal behavior latencies were studied in females HO on the 8th, 10th, 13th, 16th, or 19th day of pregnancy (8HO-19HO) and in nonpregnant HO (NPHO) females. Groups were injected sc with estradiol benzoate (EB) in doses ranging from 0 to 200 microgram(s)/kg and tested for maternal behavior (retrieving, crouching, and licking pups). In addition, we investigated whether there is an increase during pregnancy (following HO) in lordosis responsiveness to estrogen stimulation. Lordosis behavior was studied in pregnant HO females (days 8, 16, and 22) and NPHO females given 0 to 200 microgram(s)/kg EB. There was an increase in maternal responsiveness in oil-treated HO females starting around midpregnancy. From early pregnancy on there was also an increase in maternal responsiveness to 20 microgram(s)/kg EB. In late pregnant females (16HO) there was a further increase with 50 microgram(s)/kg EB. There was no increase in lordosis responsiveness to EB stimulation during pregnancy; pregnant and nonpregnant HO females had the same EB threshold for stimulating lordosis behavior. The results of both studies were related to increases during the latter half of pregnancy in nuclear estrogen receptor concentrations in the MPOA, an area that mediates estrogen stimulation of maternal behavior, and the absence of such increases during pregnancy in the VMH, an area that mediates estrogen stimulation of lordosis behavior.
本研究的目的是确定在怀孕期间，母体行为对雌激素刺激的反应性以及脊柱前凸反应性是否会增加。我们使用不同组的妊娠终止雌性动物，测量了子宫切除-卵巢切除（HO）雌性动物的初始母体反应性及其对雌激素刺激的反应性。在怀孕第8、10、13、16或19天的HO雌性动物（8HO - 19HO）以及未怀孕的HO（NPHO）雌性动物中研究了母体行为潜伏期。给各组动物皮下注射剂量范围为0至200微克/千克的苯甲酸雌二醇（EB），并测试其母体行为（找回、蹲伏和舔舐幼崽）。此外，我们研究了怀孕（HO后）期间脊柱前凸对雌激素刺激的反应性是否增加。在怀孕的HO雌性动物（第8、16和22天）以及给予0至200微克/千克EB的NPHO雌性动物中研究了脊柱前凸行为。接受油处理的HO雌性动物的母体反应性在怀孕中期左右开始增加。从怀孕早期开始，母体对20微克/千克EB的反应性也有所增加。在怀孕后期的雌性动物（16HO）中，50微克/千克EB可使其反应性进一步增加。怀孕期间脊柱前凸对EB刺激的反应性没有增加；怀孕和未怀孕的HO雌性动物刺激脊柱前凸行为的EB阈值相同。两项研究的结果都与怀孕后半期在MPOA（介导雌激素刺激母体行为的区域）中核雌激素受体浓度的增加有关，而在VMH（介导雌激素刺激脊柱前凸行为的区域）中怀孕期间没有这种增加。
