Pseudopregnancy-dependent changes in rat ovarian LH/hCG receptors in relation to membrane lipid fluidity.

Age-dependent changes in rat testicular LH/hCG receptors in relation to the membrane fluidity.

Modulation of LH/hCG receptors and physical state of ovarian membranes in rat pseudopregnancy.

Previous investigations have demonstrated that increased ovarian function during pseudopregnancy in the rat may be associated with alterations of the physical state of membranes. Changes in rigidity of membrane lipids were observed during the formation as well as regression of corpora lutea. The effects of cyclooxygenase inhibitors (indomethacin and acetylsalicylic acid (ASA)) and of selected s...

Fluorescence quenching studies of the rat ovarian LH/hCG receptor.

Fluorescence quenching method providing information about the structure and dynamics of proteins, ligand-protein and protein-lipid interactions was used in a study of the rat ovarian LH/hCG receptor. The efficiency of two different quenchers, acrylamide and iodide, was tested. Acrylamide was significantly more effective in quenching of intrinsic fluorescence of ovarian membranes than iodide and...

Changes in physical properties of ovarian membranes after hCG-induced desensitization in rats.

Using pseudopregnant rat ovaries, the possibility was examined whether hCG-induced early desensitization of the LH/hCG receptor was accompanied by changes in the physical state of membranes. Thirty min after a single s.c. injection of 75 IU hCG, the hCG-responsive adenylylcyclase activity was reduced, whereas hCG binding to ovarian membranes was still normal. Membrane lipid rigidity, as determi...

Hormonal modulation of structural alteration of rat ovarian luteinizing/human chorionic gonadotropin receptors.

The structure-stabilizing effect of homologous and heterogeneous desensitization and albumin on rat ovarian LH/hCG receptors was analyzed by thermal perturbation technique. HCG-induced down-regulation shifted the heat inactivation profile of hCG-binding sites to a temperature lower by about 7 degrees C (T50 values). In heterogeneous desensitization, which also involves uncoupling of receptors f...