TY - JOUR
T1 - 125I-Luteinizing Hormone (LH) binding to soluble receptors from the primate (Macaca mulatta) corpus luteum
T2 - Effects of ethanol exposure
AU - Danforth, Douglas R.
AU - Stouffer, Richard L.
N1 - Funding Information:
The authors appreciate the excellent technical assistance of Jesslca Lichter and Martin Grodln, and would llke to thank Pat Kosharek for her help in preparing this manuscript. We are grateful to Serono Laboratories for their generous donation of Pergonal, and to Ayerst Laboratories for their kind gift of APL. This work was performed in the Department of Physiology at the University of Arizona, College of Medicine in Tucson, AZ and supported in part by NIH grants HD-12333 and HL-07249. R.L. Stouffer is the recipient of NIH RCDA HD-00488.
PY - 1988
Y1 - 1988
N2 - In vitro exposure to alcohols unmasks additional binding sites for gonadotropin in cell/membrane preparations of the corpus luteum of rhesus monkeys. In the current study, we compared the effects of ethanol on gonadotropin receptors solubilized from macaque luteal membranes to those on receptors associated with the lipid bilayer. Treatment with 1% Triton X-100 for 30m min at 4C, followed by precipitation with polyethylene glycol, resulted in recovery of 50% more binding sites for 125I-human luteinizing hormone (hLH) than were available in particulate preparations (p<0.05). However, the soluble receptors displayed a 3-fold lower affinity for 125I-hLH (p<0.05). Conditions which enhanced LH binding to particulates, i.e., 1-8% ethanol at 25C, decreased specific 125I-hLH binding to soluble receptors. Steady-state LH binding to soluble receptors during incubation at 4C was half of that observed at 25C. The presence of 8% ethanol at 4C restored LH binding to levels observed in the absence of ethanol at 25C. Thus, LH binding sites in the primate corpus luteum can be effectively solubilized with Triton X-100. The different binding characteristics of particulate and soluble receptors, including the response to ethanol exposure, suggest that the lipid environment in the luteal membrane modulates the availability and affinity of gonadotropin receptors.
AB - In vitro exposure to alcohols unmasks additional binding sites for gonadotropin in cell/membrane preparations of the corpus luteum of rhesus monkeys. In the current study, we compared the effects of ethanol on gonadotropin receptors solubilized from macaque luteal membranes to those on receptors associated with the lipid bilayer. Treatment with 1% Triton X-100 for 30m min at 4C, followed by precipitation with polyethylene glycol, resulted in recovery of 50% more binding sites for 125I-human luteinizing hormone (hLH) than were available in particulate preparations (p<0.05). However, the soluble receptors displayed a 3-fold lower affinity for 125I-hLH (p<0.05). Conditions which enhanced LH binding to particulates, i.e., 1-8% ethanol at 25C, decreased specific 125I-hLH binding to soluble receptors. Steady-state LH binding to soluble receptors during incubation at 4C was half of that observed at 25C. The presence of 8% ethanol at 4C restored LH binding to levels observed in the absence of ethanol at 25C. Thus, LH binding sites in the primate corpus luteum can be effectively solubilized with Triton X-100. The different binding characteristics of particulate and soluble receptors, including the response to ethanol exposure, suggest that the lipid environment in the luteal membrane modulates the availability and affinity of gonadotropin receptors.
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U2 - 10.1016/0024-3205(88)90068-9
DO - 10.1016/0024-3205(88)90068-9
M3 - Article
C2 - 3398712
AN - SCOPUS:0023820002
SN - 0024-3205
VL - 43
SP - 635
EP - 642
JO - Life Sciences
JF - Life Sciences
IS - 7
ER -