Wegner J A, Martinez-Zaguilan R, Wise M E, Gillies R J, Hoyer P B
Department of Physiology, University of Arizona, Tucson 85724.
Endocrinology. 1990 Dec;127(6):3029-37. doi: 10.1210/endo-127-6-3029.
The effect of prostaglandin F2 alpha (PGF2 alpha) on cytosolic calcium homeostasis was studied in suspensions of ovine large or small luteal cells from superovulated ewes. In large cells loaded with fura-2 (AM), resting cytosolic-free calcium ([Ca2+]i) was 62 +/- 5 nM (Hanks' medium, pH 7.15), and PGF2 alpha (0.5 microM) induced a rapid transient increase in [Ca2+]i to 152 +/- 6 nM, which then decreased to 97 +/- 6 nM within 3 min and remained at this level for the remainder of the treatment period (10-20 min). PGF2 alpha did not alter intracellular pH (pHi) in cells loaded with snarf-1 (AM) (pHi indicator). The transient nature of the [Ca2+]i increase was due, at least in part, to the ability of PGF2 alpha to stimulate (P less than 0.05) 45Ca2+ efflux. In small cells, resting [Ca2+]i was 57 +/- 5 nM, and no change in [Ca2+]i levels or pHi occurred with the addition of PGF2 alpha. PGF2 alpha also did not affect 45Ca2+ efflux in small cells. Calcium uptake was not significantly altered by PGF2 alpha in large or small cells. Data from kinetic analysis of the calcium transient was best fit to a two-compartment model consisting of a rapidly effluxing compartment and a slowly effluxing compartment. The size and rate constants were 62 +/- 10 nM and 3.6 +/- 1 min-1, respectively, for the rapidly effluxing compartment and 140 +/- 9 nM and 0.02 +/- 0.002 min-1, respectively, for the slowly effluxing compartment. These results provide evidence for a direct effect of PGF2 alpha specifically on the ovine large luteal cell that involves alterations in [Ca2+]i and calcium flux. This effect is likely to be involved in intracellular mediation of the signal for luteal regression.
在超排母羊的大或小黄体细胞悬液中研究了前列腺素F2α（PGF2α）对细胞溶质钙稳态的影响。在负载fura-2（AM）的大细胞中，静息细胞溶质游离钙（[Ca2+]i）为62±5 nM（汉克斯培养基，pH 7.15），PGF2α（0.5 μM）诱导[Ca2+]i迅速短暂升高至152±6 nM，然后在3分钟内降至97±6 nM，并在剩余的处理期（10 - 20分钟）内维持在该水平。PGF2α未改变负载snarf-1（AM）（pHi指示剂）的细胞内pH（pHi）。[Ca2+]i升高的短暂性质至少部分归因于PGF2α刺激（P < 0.05）45Ca2+流出的能力。在小细胞中，静息[Ca2+]i为57±5 nM，添加PGF2α后[Ca2+]i水平或pHi未发生变化。PGF2α也不影响小细胞中的45Ca2+流出。PGF2α对大或小细胞中的钙摄取没有显著影响。钙瞬变的动力学分析数据最适合由快速流出区室和缓慢流出区室组成的双室模型。快速流出区室的大小和速率常数分别为62±10 nM和3.6±1 min-1，缓慢流出区室的大小和速率常数分别为140±9 nM和0.02±0.002 min-1。这些结果为PGF2α对绵羊大黄体细胞的直接作用提供了证据，该作用涉及[Ca2+]i和钙通量的改变。这种作用可能参与黄体退化信号的细胞内介导。
