George Mikhail

Plasma estrogens in postmenopausal women.

Abstract The concentration of plasma estrone and estradiol was measured in different groups of postmenopausal women; including physiologic menopause, castration menopause, and those who in addition to menopause had diabetes, hypertension, or cardiac disease. The mean values for estrone were 41 pg. per milliliter and for estradiol 13 pg. per milliliter. There was no statistical difference in the levels of plasma estrogen in all groups of postmenopausal women studied. In 3 individuals, studies of estrogens in ovarian vein blood suggested a nonovarian origin of estrogen.

ESTROGEN AND PROGESTERONE RECEPTORS IN THE FEMALE GENITAL TRACT OF HUMANS AND MONKEYS

Studies in laboratory animals have shown that responses of target organs to avarian hormones are influenced by the levels and intracellular location of specific steroid-binding proteins. I , * The cellular content of estrogen and progesterone receptors seems to be primarily regulated by the magnitude and duration of exposure of the tissues to circulating hormones. We have assessed endocrine regulation of human female genital tissues by measuring estrogen and progesterone receptors in different areas of the genital tract during the menstrual cycle, during administration of progestins and estrogens, and in some pathologic states. Other studies were performed on the genital tract of rhesus monkeys. In this primate model, the circulating levels of progesterone and estradiol were controlled by administration of hormones to castrated animals.

Estradiol Receptor in the Human Fallopian Tube

The levels of estrogen receptor in the cytosol of different segments of the human fallopian tube obtained at different times in the reproductive cycle were measured in 38 20-48 year old women undergoing surgery for pelvic disease. Estradiol binding was in the 4S and 8S regions. Excess unlabeled estradiol displaced most radioactivity from the 8S area with little effect on the 4S area. The dissociation constant of the receptor was 1.1 times 10 less than minus 9 greater than. The greatest amount of binding was seen at the ampulla with the lowest in the infundibulum. Adjacent to the corpus luteum there was an even lower level of estradiol receptor. These differences were not apparent in women taking oral contraceptives.

Estradiol binding by human endometrial tissue

Estrogen binding in endometrial tissue of various hormonal conditions was compared by a quantitative dextran-coated charcoal assay. The amount of [ 3 H]E 2 bound to cytosol in vitro was expressed as fmole/ μ g DNA and fmole/mg protein. The highest values were obtained for proliferative endometrium (1.95 ± 0.45; 244.06 ± 38.99). Endometrium from patients on oral contraceptives had low levels of estrogen receptor, which was slightly higher than that of atrophic endometrium. Various endometrial lesions were examined. The most consistent results were found for areas of hyperplastic endometrium (1.51 ± 0.41; 138.88 ± 3.43). Seventeen cases of endometrial adenocarcinoma plus one case of endocervical adenosquamous carcinoma can be divided into three groups. One-third showed no detectable estrogen binding, one group of seven patients showed low values, and a third group of five patients had high concentrations of estrogen receptors.

Cytosol and nuclear estrogen receptor in the genital tract of the rhesus monkey

Abstract Estrogen receptor levels of cytosol and nuclei were measured in the cervix, vagina, myometrium, and endometrium of the rhesus monkey after the following experimental treatments: (1) castration; (2) castration with estradiol treatment; and (3) castration with estradiol plus progesterone treatment. Plasma hormone levels similar to those of normal menstrual cycles were achieved by implantation of silastic capsules containing estradiol or progesterone. The K D , 4 × 10 −9 M, for the cytosol receptor was similar in all tissues. Competition studies showed cytosol receptor affinities to be E 2 > e 1 > E 3 > DES. Cytosol receptor levels in estrogenized animals were lowered by progesterone treatment. Progesterone treatment did not alter the levels of nuclear receptor indicating that the lower levels of cytosol receptor obtained with progesterone were not due to nuclear translocation of cytosol receptor. Estrogen treatment changed the sedimentation coefficient of the endomentrial and myometrial cytosol receptor from 4 s to 8 s when compared with the castrate. This alteration in sedimentation coefficient was blocked by progesterone treatment. Changes in sedimentation coefficient were not observed in the cervix or vagina. Nuclear receptor in estrogen and estrogen plus progesterone treated animals sedimented as a 5 s protein. The data suggest that both qualitative and quantitative changes in the estradiol cytosol receptor of the genital tract are induced by progesterone and that these alterations may be related to the hormone interactions in target organs.

Progesterone binding in rabbit oviduct and uterus.

Summary Progesterone binding of high affinity with a dissociation constant of 10-9 M was identified in cytosol of rabbit oviduct and uterus. Macromolecules with sedimentation coefficients of 7-8 S and 4-5 S were present. Progesterone receptor concentration was two to fivefold lower in the oviduct when compared with the uterus. The receptor concentration declined steadily from 3 hr until 144 hr after mating in the uterus; however, the decline in oviductal receptor was not significant until the sixth day of pregnancy. Progesterone receptor concentration in rabbit oviduct and uterus in estrus and early pregnancy was greater than estradiol receptor levels.

A specific progesterone receptor of myometrial cytosol from the rhesus monkey

A specific progesterone receptor of myometrial cytosol from the rhesus monky is described. Characterization of the receptor by sucrose density gradient centrifugation revealed 2 peaks at 4s and 7.5s. The 4s peak seen in all groups (castrate; castrate plus estrogen treated; castrate plus estrogen and progesterone treated) contained little specific progesterone binding but the 7.5s peak, seen only in the estrogen-treated animal, was specific for progesterone. Competition studies revealed the reeceptor affinities to be: progesterone 100, 5alpha dehydroprogesterone 81.9 melengestrol acetate 72.5, norgestrel 53, desoxycorticosterone 25.9, 5beta-dihydroprogesterone 1.2, and 17 hydroxyprogesterone less than 1. Receptor levels measured from Scatchard plot analysis of of equilibrium data were 7 fM/mg cytosol protein (castrate), 45.2 fM/mg (p less than .01, estrogen treated), and 10.5 (estrogen plus progesterone treated). The association constant (approximately 5 x 10(-9)M) was similar in all 3 groups.

Free and protein-bound steroids in amniotic fluid of midpregnancy

Ninety-seven amniotic fluid (AF) specimens, 67 with male fetuses and 30 with female fetuses, were obtained by amniocentesis at 14 to 18 weeks of gestation for analysis of free and protein-bound estrone (E1), estradiol (E2), androstenedione (A), testosterone (T), and progesterone (P). Ten maternal plasma (MP) samples of comparable gestational age were analyzed for the same free and protein-bound steroids. Significantly lower total E1, E2, A, and T, but not P, levels were found in AF when compared to MP. The percentage of free steroids was higher in AF than in MP, while the percentage of specific protein-bound steroids was lower in the AF than in MP. Free (unbound) steroid levels of E1 and P were higher in AF than in MP, whereas levels of E2 were lower in AF than in MP. The free A and T levels in MP were lower than in AF with male fetuses, yet higher than in AF with female fetuses. Possible biologic activity of steroids in this fluid may depend on the dynamic balance between the free, the specific protein-bound, and the nonspecific protein-bound steroids.

Search for arteriovenous shunts in the genital tract of the pseudopregnant rabbit.

Introduction. The blood flow within an endocrine gland plays an essential role in the control of its physiological activities. Some of the complex hemodynamics changes of the ovary have been described during the preovulatory period ( 1 ), pseudo-pregnancy ( 2 , 3 ), and pregnancy ( 4 ). The mechanisms that regulate these changes are not clear, but hormones ( 5 , 6 ) and amines have been implicated in circulatory control ( 7 ). The luteolytic process is characterized by a remarkable decline in ovarian blood flow ( 4 ) and progesterone secretion ( 8 ). The drop in blood flow to the corpus luteum has been attributed to the presence of arteriovenous shunts which would divert blood flow from the corpus luteum ( 9 ). In this report we present evidence indicating that, in the pseudopregnant rabbit, no demonstrable arteriovenous shunts are found in the ovary. Materials and methods. Mature New Zealand White rabbits, 3-4 kg in weight, were kept in individual cages for 3 weeks prior to use. Blood flow determinations were carried out 6, 12, and 18 days after iv administration of 100 IU of hCG. Analgesia was induced with Innovar (0.2 mg/kg) administered intramuscularly. Both femoral arteries were catheterized with a poly vinyl tube (PE. 60, Clay-Adams, N.J.). The right catheter was advanced until its tip was about 3 cm below the diaphragm. This catheter was used for the administration of radioactive microspheres. The left femoral catheter was advanced about 2 cm into the artery and connected to a Harvard pump. Each animal received approximately 1,500,000 micro-spheres, 15 ± 5-μM diameter, labeled with St85 and 400,000 microspheres, 50 ± 5-μm diameter, labeled with CE141 (3M Company, St. Paul, Minn.). The spheres were suspended in 0.8 ml of 10% dextran in physiologic saline, mixed well, and injected immediately through the right femoral catheter.

Estrogen-Androgen Balance in Anovulation

The balance of estradiol (E2) and testosterone (T) in 15 anovulatory patients was evaluated by measuring the daily plasma concentration of E2 and T, and their free and protein-bound fractions for a 3- to 4-week period. Similar daily plasma E2 and T data were obtained from five normal ovulatory cycles as a control group. The daily concentration of the free, non-testosterone-estradiol-binding globulin (TeBG)-bound (index), and total E2 fluctuated in a wider range than that of the T in the ovulatory as well as in the anovulatory cycles. The percentage of free (%F) and TeBG-bound (%TeBG) fractions of both E2 and T were relatively constant. The concentration of the free, index, and total E2 and T showed a parallel pattern even in anovulatory cycles. An increased %F fraction associated with a decreased %TeBG fraction of E2 and T was observed in anovulatory patients who were hypo- or normoestrogenic; however, an opposite shifting of these two fractions was observed in anovulatory patients who were severely hypoestrogenic. In a hyperestrogen-normoandrogenic state, there was a significant increase in the binding of E2 and T. The daily binding capacity of plasma TeBG revealed a greater fluctuation than the binding fractions, and it decreased in anovulatory patients, especially in the hyperandrogenic state. E2:T ratio of concentration showed a curve-linear relationship to %F, %TeBG, and binding capacity of sex steroids.