|
|
||||||||
The refractoriness of LH release by pituitary glands from intact female rats was studied during stimulation by luteinizing hormone releasing hormone (LH-RH), monobutyryl cyclic AMP+theophylline or potassium in vitro. Various concentrations of LH-RH (0·1, 0·3 and 10 ng/ml) all caused refractoriness within 24 h. Subsequent exposure to a supramaximally active concentration of LH-RH for 6 h also resulted in a depressed response; the degree of inhibition depended on the concentration of LH-RH to which the glands had been exposed previously. Glands made refractory to LH-RH also showed a depressed response to monobutyryl cyclic AMP+theophylline, although these agents by themselves were unable to induce refractoriness. Incubation in medium containing a high concentration of potassium also resulted in the release of LH, which in all respects was similar to that caused by LH-RH. Glands made refractory to LH-RH showed a decreased response to potassium and, conversely, the release of LH in response to LH-RH was reduced after exposure of glands to potassium.
It is concluded that the LH releasing activity of LH-RH, which is mimicked by potassium, deteriorates during continuous exposure to the secretagogue.
This article has been cited by other articles:
![]() |
C. A. McArdle, G. B. Willars, R. C. Fowkes, S. R. Nahorski, J. S. Davidson, and W. Forrest-Owen Desensitization of Gonadotropin-releasing Hormone Action in alpha T3-1 Cells Due to Uncoupling of Inositol 1,4,5-Trisphosphate Generation and Ca2+ Mobilization J. Biol. Chem., September 27, 1996; 271(39): 23711 - 23717. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |