PMID- 7956933
OWN - NLM
STAT- MEDLINE
DCOM- 19941216
LR  - 20181130
IS  - 0013-7227 (Print)
IS  - 0013-7227 (Linking)
VI  - 135
IP  - 5
DP  - 1994 Nov
TI  - Differential regulation of Ca2+ homeostasis in ovine large and small luteal 
      cells.
PG  - 2099-108
AB  - This study was undertaken to characterize differences in Ca2+ homeostasis between 
      small and large ovine luteal cells. Although increasing extracellular pH (pHex) 
      resulted in increases in intracellular calcium ([Ca2+]in) in both cell types, the 
      large cells exhibited a greater sensitivity, suggesting that distinct [Ca2+]in 
      regulatory mechanisms with distinct pH optima are operating in the two cell 
      types. The sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase inhibitors 
      thapsigargin (TG) and cyclopiazonic acid (CPA) increased [Ca2+]in in both cell 
      types. Treatment of small cells with CPA resulted in transient increases in 
      [Ca2+]in, whereas CPA produced sustained increases in [Ca2+]in in large cells. In 
      small cells, pretreatment with CPA prevented further increases in [Ca2+]in in 
      response to TG and vice versa. In large cells, TG pretreatment precluded further 
      increases in [Ca2+]in with either prostaglandin F2 alpha (PGF2 alpha) or CPA. In 
      contrast, after CPA pretreatment, PGF2 alpha or TG induced further increases in 
      [Ca2+]in in large cells. This suggests that a TG-sensitive, CPA-insensitive Ca2+ 
      pool is present in large cells but not in small cells. Neither Na+ removal nor 
      KCl addition affected [Ca2+]in in either cell type, indicating that neither the 
      Na+/Ca2+ exchanger nor voltage-dependent Ca2+ channels are involved in Ca2+ 
      homeostasis in these cells. Addition of the calcium antagonist, LaCl3 (La3+), 
      produced a gradual increase in [Ca2+]in in large cells but no changes in [Ca2+]in 
      in small cells. Additionally, treatment with increasing concentrations of 
      4-bromo-A23187 resulted in titratable increases in [Ca2+]in that are greater in 
      large than small cells, suggesting that small cells possess a higher 
      Ca(2+)-buffering capacity than large cells. Progesterone secretion by large cells 
      was significantly inhibited at alkaline pHex. In the presence of PGF2 alpha, 
      progesterone secretion exhibited a distinct pH optimum of 7.0. In contrast, pHex 
      did not affect secretion of progesterone in small cells under any of the 
      conditions tested. TG, CPA, and La3+ all reduced secretion of progesterone in 
      large, but not small, cells. These results demonstrate that ovine large and small 
      luteal cells differ in regulation of [Ca2+]in homeostasis, and that treatments 
      that increase [Ca2+]in decrease progesterone secretion in large cells but have no 
      effect in small cells.(ABSTRACT TRUNCATED AT 400 WORDS)
FAU - Martinez-Zaguilan, R
AU  - Martinez-Zaguilan R
AD  - Department of Biochemistry, University of Arizona, Tucson 85724.
FAU - Wegner, J A
AU  - Wegner JA
FAU - Gillies, R J
AU  - Gillies RJ
FAU - Hoyer, P B
AU  - Hoyer PB
LA  - eng
GR  - HD-00907/HD/NICHD NIH HHS/United States
GR  - HD-26778/HD/NICHD NIH HHS/United States
GR  - HL-07249/HL/NHLBI NIH HHS/United States
GR  - etc.
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Endocrinology
JT  - Endocrinology
JID - 0375040
RN  - 0 (Calcium Channels)
RN  - 0 (Carrier Proteins)
RN  - 0 (Indoles)
RN  - 0 (Sodium-Calcium Exchanger)
RN  - 0 (Terpenes)
RN  - 4G7DS2Q64Y (Progesterone)
RN  - 67526-95-8 (Thapsigargin)
RN  - B7IN85G1HY (Dinoprost)
RN  - SY7Q814VUP (Calcium)
RN  - X9TLY4580Z (cyclopiazonic acid)
SB  - IM
MH  - Animals
MH  - Calcium/*metabolism
MH  - Calcium Channels/analysis/physiology
MH  - Carrier Proteins/physiology
MH  - Corpus Luteum/*cytology/*metabolism/physiology
MH  - Dinoprost/pharmacology
MH  - Female
MH  - Homeostasis/drug effects/*physiology
MH  - Hydrogen-Ion Concentration
MH  - Indoles/pharmacology
MH  - Progesterone/metabolism
MH  - Sheep/*physiology
MH  - Sodium-Calcium Exchanger
MH  - Terpenes/pharmacology
MH  - Thapsigargin
EDAT- 1994/11/01 00:00
MHDA- 1994/11/01 00:01
CRDT- 1994/11/01 00:00
PHST- 1994/11/01 00:00 [pubmed]
PHST- 1994/11/01 00:01 [medline]
PHST- 1994/11/01 00:00 [entrez]
AID - 10.1210/endo.135.5.7956933 [doi]
PST - ppublish
SO  - Endocrinology. 1994 Nov;135(5):2099-108. doi: 10.1210/endo.135.5.7956933.