Abstract
A previous study demonstrated that prostaglandin F2α (PGF2α) stimulates a transient increase in cytosolic free Ca2+ levels ([Ca2+]i) in ovine large luteal cells. In the present study, the magnitude of the PGF2α (0.5 μM)-induced calcium transient in Hanks' medium (87 ± 2 nM increase above resting levels) was reduced (P < 0.05) but not completely eliminated in fura-2 loaded large luteal cells incubated in Ca2+-free or phosphate- and carbonate-free medium (10 ± 1 nM, 32 ± 6 nM, above resting levels; respectively). Preincubation for 2 min with 1 mM LaCl3 (calcium antagonist) eliminated the PGF2α-induced calcium transient. The inhibitory effect of PGF2α on secretion of progesterone was reduced in Ca2+-free medium or medium plus LaCl3. Resting [Ca2+]i levels and basal secretion of progesterone were both reduced (P < 0.05) in large cells incubated in Ca2+-free medium (27 ± 4 nM; 70 ± 6% control, respectively) or with 5 μM 5,5′-dimethyl bis-(O-aminophenoxy)ethane-N,N,N′N′-tetraacetic acid (40 ± 2 nM; 49 ± 1% control; respectively). In addition, secretion of progesterone was inhibited (P < 0.05) by conditions that increased (P < 0.05) [Ca2+]i; that is LaCl3 ([Ca2+]i, 120 ± 17 nM; progesterone, 82 ± 8% control) and PGF2α ([Ca2+]i, 102 ± 10 nM; progesterone, 82 ± 3% control). In small luteal cells, resting [Ca2+]i levels and secretion of progesterone were reduced by incubation in Ca2+-free Hanks ([Ca2+]i, 28 ± 2 nM; progesterone, 71 ± 6% control), however, neither LaCl3 nor PGF2α increased [Ca2+]i levels or inhibited secretion of progesterone. The findings presented here provide evidence that extracellular as well as intracellular calcium contribute to the PGF2α-induced [Ca2+]i transient in large cells. Furthermore, whereas an adequate level of [Ca2+]i is required to support progesterone production in both small and large cells, optimal progesterone production in large cells depends upon an appropriate window of [Ca2+]i.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 929-936 |
| Number of pages | 8 |
| Journal | Endocrinology |
| Volume | 128 |
| Issue number | 2 |
| State | Published - Feb 1991 |
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ASJC Scopus subject areas
- Endocrinology
- Endocrinology, Diabetes and Metabolism
Cite this
Prostaglandin F2α-induced calcium transient in ovine large luteal cells : II. Modulation of the transient and resting cytosolic free calcium alters progesterone secretion. / Wegner, J. A.; Martinez-Zaguilan, R.; Gillies, R. J.; Hoyer, Patricia B.
In: Endocrinology, Vol. 128, No. 2, 02.1991, p. 929-936.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Prostaglandin F2α-induced calcium transient in ovine large luteal cells
T2 - II. Modulation of the transient and resting cytosolic free calcium alters progesterone secretion
AU - Wegner, J. A.
AU - Martinez-Zaguilan, R.
AU - Gillies, R. J.
AU - Hoyer, Patricia B
PY - 1991/2
Y1 - 1991/2
N2 - A previous study demonstrated that prostaglandin F2α (PGF2α) stimulates a transient increase in cytosolic free Ca2+ levels ([Ca2+]i) in ovine large luteal cells. In the present study, the magnitude of the PGF2α (0.5 μM)-induced calcium transient in Hanks' medium (87 ± 2 nM increase above resting levels) was reduced (P < 0.05) but not completely eliminated in fura-2 loaded large luteal cells incubated in Ca2+-free or phosphate- and carbonate-free medium (10 ± 1 nM, 32 ± 6 nM, above resting levels; respectively). Preincubation for 2 min with 1 mM LaCl3 (calcium antagonist) eliminated the PGF2α-induced calcium transient. The inhibitory effect of PGF2α on secretion of progesterone was reduced in Ca2+-free medium or medium plus LaCl3. Resting [Ca2+]i levels and basal secretion of progesterone were both reduced (P < 0.05) in large cells incubated in Ca2+-free medium (27 ± 4 nM; 70 ± 6% control, respectively) or with 5 μM 5,5′-dimethyl bis-(O-aminophenoxy)ethane-N,N,N′N′-tetraacetic acid (40 ± 2 nM; 49 ± 1% control; respectively). In addition, secretion of progesterone was inhibited (P < 0.05) by conditions that increased (P < 0.05) [Ca2+]i; that is LaCl3 ([Ca2+]i, 120 ± 17 nM; progesterone, 82 ± 8% control) and PGF2α ([Ca2+]i, 102 ± 10 nM; progesterone, 82 ± 3% control). In small luteal cells, resting [Ca2+]i levels and secretion of progesterone were reduced by incubation in Ca2+-free Hanks ([Ca2+]i, 28 ± 2 nM; progesterone, 71 ± 6% control), however, neither LaCl3 nor PGF2α increased [Ca2+]i levels or inhibited secretion of progesterone. The findings presented here provide evidence that extracellular as well as intracellular calcium contribute to the PGF2α-induced [Ca2+]i transient in large cells. Furthermore, whereas an adequate level of [Ca2+]i is required to support progesterone production in both small and large cells, optimal progesterone production in large cells depends upon an appropriate window of [Ca2+]i.
AB - A previous study demonstrated that prostaglandin F2α (PGF2α) stimulates a transient increase in cytosolic free Ca2+ levels ([Ca2+]i) in ovine large luteal cells. In the present study, the magnitude of the PGF2α (0.5 μM)-induced calcium transient in Hanks' medium (87 ± 2 nM increase above resting levels) was reduced (P < 0.05) but not completely eliminated in fura-2 loaded large luteal cells incubated in Ca2+-free or phosphate- and carbonate-free medium (10 ± 1 nM, 32 ± 6 nM, above resting levels; respectively). Preincubation for 2 min with 1 mM LaCl3 (calcium antagonist) eliminated the PGF2α-induced calcium transient. The inhibitory effect of PGF2α on secretion of progesterone was reduced in Ca2+-free medium or medium plus LaCl3. Resting [Ca2+]i levels and basal secretion of progesterone were both reduced (P < 0.05) in large cells incubated in Ca2+-free medium (27 ± 4 nM; 70 ± 6% control, respectively) or with 5 μM 5,5′-dimethyl bis-(O-aminophenoxy)ethane-N,N,N′N′-tetraacetic acid (40 ± 2 nM; 49 ± 1% control; respectively). In addition, secretion of progesterone was inhibited (P < 0.05) by conditions that increased (P < 0.05) [Ca2+]i; that is LaCl3 ([Ca2+]i, 120 ± 17 nM; progesterone, 82 ± 8% control) and PGF2α ([Ca2+]i, 102 ± 10 nM; progesterone, 82 ± 3% control). In small luteal cells, resting [Ca2+]i levels and secretion of progesterone were reduced by incubation in Ca2+-free Hanks ([Ca2+]i, 28 ± 2 nM; progesterone, 71 ± 6% control), however, neither LaCl3 nor PGF2α increased [Ca2+]i levels or inhibited secretion of progesterone. The findings presented here provide evidence that extracellular as well as intracellular calcium contribute to the PGF2α-induced [Ca2+]i transient in large cells. Furthermore, whereas an adequate level of [Ca2+]i is required to support progesterone production in both small and large cells, optimal progesterone production in large cells depends upon an appropriate window of [Ca2+]i.
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M3 - Article
C2 - 1899223
AN - SCOPUS:0025924122
VL - 128
SP - 929
EP - 936
JO - Endocrinology
JF - Endocrinology
SN - 0013-7227
IS - 2
ER -