Gorospe W C, Freeman M E
Endocrinology. 1985 Apr;116(4):1559-64. doi: 10.1210/endo-116-4-1559.
We have shown that the uterus of the rat contains a substance that diminishes the release of the luteotropic hormone PRL by acting directly at the anterior pituitary gland. This study was designed to determine which cell type(s) within the uterus secretes this PRL inhibitory activity (PIA) and if PIA of uterine origin appears in circulation. Enzymatically dispersed cells from uteri of ovariectomized (OVX) rats were cultured for 24 h in serum-free Dulbecco's Modified Eagle's Medium. Estimation of PIA in the spent media from heterogeneous uterine cell cultures was evaluated after 24 h by the ability to suppress PRL release from confluent monolayers of cultured pituitary cells. Spent media from uterine cell cultures containing 0.125 X 10(6) or 0.25 X 10(6) cells/well failed to significantly suppress PRL secretion. However, media from 0.5 X 10(6) and 1 X 10(6) uterine cells/well induced 36% and 85% inhibition of PRL release, respectively, without affecting basal LH release. To determine which cell type(s) in the uterus is responsible for PIA secretion, whole uteri were partitioned into epithelial, stromal, and myometrial cell fractions by differential enzymatic dissociation. Varying numbers of cells from each fraction were cultured for 24 h. PIA in the spent media from the homogeneous uterine cell cultures was estimated by its ability to suppress PRL release from cultured anterior pituitary cells. Media from epithelial cell cultures suppressed PRL secretion in a dose-dependent fashion. Media obtained from cultures of a comparable number of stromal or myometrial cells had no significant effects on PRL secretion. LH secretion was unaffected by media obtained from any concentration of the various uterine cell types. Since cultured anterior pituitary cells treated directly with crude uterine extract for 24 h recover and secrete PRL at the same rate as untreated controls during a 72-h posttreatment interval, it is unlikely that the uterine PIA is either proteolytic or cytotoxic. To determine if PIA is detectable in peripheral circulation, sera obtained from OVX or OVX hysterectomized (OVX-HYST) donor rats were incubated with cultured anterior pituitary cells for 24 h. In response to the OVX sera, there was significant inhibition of PRL release. However, upon replacement of OVX sera with OVX-HYST sera, the inhibition was significantly reduced. Thus, PIA is higher in sera of rats bearing uteri. Taken together, these data suggest that the epithelial layer of the uterus secretes a PIA which probably reaches the hypothalamo-pituitary axis through the circulation.
我们已经证明，大鼠子宫中含有一种物质，该物质通过直接作用于垂体前叶来减少促黄体激素PRL的释放。本研究旨在确定子宫内哪种细胞类型分泌这种PRL抑制活性（PIA），以及子宫来源的PIA是否会出现在循环中。将去卵巢（OVX）大鼠子宫的酶分散细胞在无血清的杜氏改良 Eagle 培养基中培养24小时。24小时后，通过抑制培养的垂体细胞汇合单层释放PRL的能力来评估异质性子宫细胞培养物的用过培养基中的PIA。含有0.125×10⁶或0.25×10⁶个细胞/孔的子宫细胞培养物的用过培养基未能显著抑制PRL分泌。然而，来自0.5×10⁶和1×10⁶个子宫细胞/孔的培养基分别诱导PRL释放抑制36%和85%，而不影响基础LH释放。为了确定子宫中哪种细胞类型负责PIA分泌，通过差异酶解离将整个子宫分为上皮、基质和肌层细胞部分。将来自每个部分的不同数量的细胞培养24小时。通过其抑制培养的垂体前叶细胞释放PRL的能力来估计均匀子宫细胞培养物的用过培养基中的PIA。来自上皮细胞培养物的培养基以剂量依赖性方式抑制PRL分泌。从相当数量的基质或肌层细胞培养物中获得的培养基对PRL分泌没有显著影响。LH分泌不受任何浓度的各种子宫细胞类型的培养基的影响。由于在72小时的处理后间隔期间，直接用粗制子宫提取物处理24小时的培养垂体前叶细胞恢复并以与未处理对照相同的速率分泌PRL，因此子宫PIA不太可能是蛋白水解性的或细胞毒性的。为了确定外周循环中是否可检测到PIA，将从OVX或OVX子宫切除（OVX-HYST）供体大鼠获得的血清与培养的垂体前叶细胞孵育24小时。响应OVX血清，PRL释放受到显著抑制。然而，用OVX-HYST血清替代OVX血清后，抑制作用显著降低。因此，有子宫的大鼠血清中PIA含量更高。综上所述，这些数据表明子宫的上皮层分泌一种PIA，它可能通过循环到达下丘脑-垂体轴。
