Human chorionic gonadotropin (hCG) increases cytosolic free calcium in adult rat Leydig cells

Cell Calcium ◽  
1994 ◽  
Vol 15 (5) ◽  
pp. 349-355 ◽  
Author(s):  
S. Kumar ◽  
D.L. Blumberg ◽  
J.A. Canas ◽  
V.T. Maddaiah
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Leydig Cells ◽  
Free Calcium ◽  
Cytosolic Free Calcium ◽  
Adult Rat

Isolation of rat Leydig cells and precursor forms after administration of ethane dimethane sulfonate

1994 ◽  
Vol 266 (6) ◽  
pp. E975-E979 ◽  
Author(s):  
G. P. Risbridger ◽  
A. Davies
Keyword(s):  
Luteinizing Hormone ◽  
Cell Population ◽  
Chorionic Gonadotropin ◽  
Leydig Cell ◽  
Human Chorionic Gonadotropin ◽  
Leydig Cells ◽  
Steroid Production ◽  
Microscopic Appearance ◽  
Rat Testis ◽  
Adult Rat

The cytotoxic drug ethane dimethane sulfonate (EDS) has been extensively used as a means of studying the regeneration of Leydig cells in the adult rat testis. This study used the EDS-treated rat testis as a source of material for the isolation of regenerating Leydig cells and their precursors and describes the procedures required for the isolation of these cell preparations. As early as 13-15 days after EDS, cells in the precursor fraction can bind low, but detectable, levels of iodinated purified human chorionic gonadotropin. However, no luteinizing hormone (LH) response was detected in terms of steroid production. The precursor fraction of cells isolated from the EDS-treated rat testis 17-19 days after the administration of EDS was heterogeneous in light-microscopic appearance, but identifiable Leydig-like cells were present. The cells in this fraction were the first to exhibit the ability to respond to LH with the production of detectable levels of the reduced androgen, 5 alpha-androstane-3 alpha,17 beta-diol. The amount of androgen produced by both the Leydig cell and precursor fractions had increased by 21 days after EDS and reached the levels produced by immature adultlike Leydig cells, which can be isolated from the 20-day-old rat testes. These studies demonstrate that steroidogenically responsive precursor forms of Leydig cells can be isolated from the EDS-treated testes 17-19 days after depletion of the adult Leydig cell population.

The Effect of Verapamil and Diltiazem on Alveolar Type II Cells during Warm and Cold Metabolic Ischaemia

1994 ◽  
Vol 22 (3) ◽  
pp. 153-159
Author(s):  
L Spaggiari ◽  
M Rusca ◽  
R Alfieri ◽  
P G Petronini ◽  
P Carbognani ◽  
...  
Keyword(s):  
Calcium Channel ◽  
Calcium Channel Blockers ◽  
Total Protein Content ◽  
Free Calcium ◽  
Alveolar Type ◽  
Channel Blockers ◽  
Type Ii ◽  
Organ Protection ◽  
Cytosolic Free Calcium ◽  
Adult Rat

The alteration of cytosolic free calcium concentration is an important event during cellular ischaemia. Calcium channel blockers have been shown to be beneficial during experimental ischaemic organ protection. To investigate the mechanisms of this protection, the behaviour of type II pneumocyte cultures, subjected to warm and cold metabolic ischaemia (6 h), was studied. The cells were incubated in electrolytic solutions and treated with high doses of verapamil (10 mg/l) or diltiazem (100 mg/l). Alveolar type II epithelial cells were removed from adult rat lungs using the modified Dobbs' method. Cell viability was determined by analysis of the total protein content, and from the rate of protein synthesis as indicated by the [35S]methionine uptake assay. The results show that verapamil does not have a direct cytoprotective or cytotoxic effect on the incubated cells, but diltiazem seems to be toxic to the cells, especially during cold ischaemia when the toxicity is significant ( P < 0.05). Thus, the protection from ischaemia previously attributed to calcium channel blockers is ascribed to action on the blood vessels resulting in vasodilatation, rather than to a direct influence on cytosolic free calcium homeostasis.

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