Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A deficiency of luteal cell prostaglandin F2 alpha (PGF2 alpha) receptors might help explain the well documented refractoriness of pig corpora lutea to the luteolytic effects of PGF2 alpha administered in vivo before day 12 of the estrous cycle. Accordingly, experiments were conducted to measure the levels of [3H] PGF2 alpha-binding sites/receptors on collagenase-dispersed pig luteal cells taken at different stages of the estrous cycle. Pig corpora lutea were obtained surgically at various stages of the estrous cycle and dissociated with collagenase in medium 199. Dissociated mixed luteal cells (approximately 5-15 x 10(4) large luteal cells/tube) were assayed for [3H]PGF2 alpha-binding activity by saturation (Scatchard) analysis. In preliminary experiments it was determined that PGF2 alpha binding was maximal after incubation for 45 min at 30 C in assay buffer of pH 5.75. Additionally, it was determined that [3H]PGF2 alpha binding was displaceable by PGF2 alpha = PGD2 greater than PGE2 greater than 13,14-dihydro-15-keto-PGF2 alpha. Other eicosanoids did not inhibit [3H]PGF2 alpha binding. Two distinct classes of binding sites (high affinity Kd = 19-64 nM; low affinity Kd = 262-3103 nM) were observed at all stages of the estrous cycle. From studies using enriched (by elutriation) large (greater than 30 microns) and small (10-20 microns) luteal cells it appeared that the high affinity binding site was largely confined to large luteal cells, whereas the low affinity binding site was found on both large and small luteal cells. The concentrations (number per large luteal cell) of high affinity PGF2 alpha-binding sites of mixed (unelutriated) luteal cell preparations was low on days 6-8 (0.6 x 10(6) sites/cell) and increased gradually up to 1.4 x 10(6) sites/cell on day 12. The concentrations of binding sites were increased approximately 3-fold on day 13 (4.6 x 10(6) sites/cell; P less than 0.05 vs days 6-12) and remained elevated on days 14 and 16-17 (approximately 3 x 10(6) sites/cell). In summary, these results indicate the existence of a high affinity PGF2 alpha-binding site in pig (large) luteal cells, which is probably the luteal PGF2 alpha receptor. The numbers of these putative PGF2 alpha receptors are low during the early luteal phase (before day 12), but increase thereafter (days 13, 14, and 16-17). This may provide one explanation for the observed refractoriness in vivo of pig corpora lutea to PGF2 alpha before, and increased sensitivity to PGF2 alpha after, day 12 of the estrous cycle.
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PMID:Prostaglandin F2 alpha receptors on enzyme-dissociated pig luteal cells throughout the estrous cycle. 215 25

In this study we examined the stimulatory effects of PGF2 alpha on progesterone secretion by porcine luteal cells on different days of the estrous cycle, and the effects of PGF2 alpha, A23187 and PMA on progesterone secretion by isolated large and small luteal cells, in vitro. Corpora lutea were obtained from cycling pigs (days 6-16), collagenase dispersed and luteal cells incubated in medium 199 in the absence or presence of increasing doses of PGF2 alpha, A23187, and PMA. Progesterone concentrations in spent media were measured by RIA. PGF2 alpha stimulation of progesterone secretion by mixed luteal cells did not vary significantly throughout the estrous cycle. Progesterone secretion by large, but not small, luteal cells was increased (p < 0.05) in a dose-dependent fashion by PGF2 alpha. A23187 also caused a dose-dependent increase in progesterone secretion by large luteal cells but inhibited small luteal cells. Progesterone secretion by both large and small luteal cells was significantly increased by increasing doses of PMA. We conclude that the stimulatory response of luteal cells to PGF2 alpha in vitro did not correlate with PGF2 alpha receptor concentrations (not measured in this study), and we speculate that calcium/protein kinase C may be involved in mediating the stimulatory action of PGF2 alpha on luteal cell progesterone secretion.
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PMID:Prostaglandin F2 alpha stimulates progesterone secretion by porcine luteal cells in vitro throughout the estrous cycle. 799 75