Insulin-like growth factor I receptors in human corpora lutea.
OBJECTIVE
To determine the presence and binding characteristics of insulin-like growth factor (IGF) receptors in corpora lutea (CL) of spontaneous and clomiphene citrate (CC)-induced cycles and to identify any relationship between IGF receptors and cytosol progesterone (P) and 17 alpha-hydroxyprogesterone (17 alpha-OHP) levels.


METHODS
Women undergoing bilateral tubal ligation were divided into two groups. One group received no medication (controls) and the other took 50 mg of CC. Midluteal phase CL were recovered at tubal ligation for hormone and receptor analysis.


METHODS
Patients were recruited from a university hospital setting.


METHODS
Eleven fertile women 26 to 37 years of age requesting bilateral tubal ligation were studied.


METHODS
Four women were given 50 mg/d of CC from days 5 through 9 of study cycle. Seven women did not take any medication. Minilaparotomy bilateral tubal ligation and luteectomy were performed 7 to 9 days after midcycle urinary (LH) surge.


METHODS
Insulin-like growth factor receptor concentrations and binding characteristics and cytosol P and 17 alpha-OHP levels in individual CL.


RESULTS
Optimal binding for 125I-IGF-I with membrane fractions of homogenized CL was obtained with incubation at 4 degrees C for 16 hours. Specific binding (mean +/- SEM) was significantly higher in CC-treated (53.6% +/- 4.8%) than in control cycles (25.9% +/- 5.5%, P less than 0.001). Receptor concentrations were also significantly higher in CL from CC-induced (145.6 +/- 21.8 pmol/mg protein) than from control cycles (74.8 +/- 15.2 pmol/mg protein, P less than 0.02). Insulin-like growth factor receptor levels correlated with neither serum nor cytosol P and 17 alpha-OHP in CL from either cycles.


CONCLUSIONS
Specific IGF-I receptors are present in human CL of the menstrual cycle with higher concentrations present in CC-induced cycles. Thus IGF may express its action on luteal function through its receptors in CL.
Obasiolu
C C
CC
Department of Obstetrics and Gynecology, University of Illinois College of Medicine, Chicago.
Khan-Dawood
F S
FS
Dawood
M Y
MY
D000328:Adult; D002352:Carrier Proteins / Q000032:analysis; D003338:Corpus Luteum / Q000378:metabolism*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D009994:Osmolar Concentration; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017451:Receptors, Somatomedin
D002352:Carrier Proteins; D012739:Gonadal Steroid Hormones; D018969:Insulin-Like Growth Factor Binding Proteins; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I