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Biomedical subjects

G L Flickinger

Publications and source records attributed to G L Flickinger.

At least 55 records · Page 3Linked to original sources
PubMed1976

Free and protein-bound plasma estradiol-17 beta during the menstrual cycle.

Methods are described for the measurement of the estradiol-binding capacity of TeBG and of the free, TeBG-bound, and non-specifically protein-bound fractions of plasma estradiol. Each determination used undiluted plasma at 37 C, and a total volume of less than 2.0 ml of plasma was required to complete all the assays. The measurement of the per cent of free estradiol was affected by changes in plasma dilution. The measurement of the other fractions of estradiol was not influenced by changes in either the dilution or the volume of plasma. The distribution of plasma estradiol was determined daily throughout 5 individual menstrual cycles. The per cent of free, the per cent of TeBG-bound, and the TeBG binding capacity of estradiol remained constant throughout the cycle with mean values of 2.21 +/- 0.04% (SE), 38.4 +/- 0.7%, and 16.6 +/- 0.43 ng/ml, respectively. The mean association constant of TeBG for estradiol was 6.58 +/- 0.25 x 10(7)M-1. The concentration of the free and non-specifically protein-bound fractions of estradiol paralleled the total plasma concentration of estradiol. The results show that biologic events related to normal cyclic changes of plasma estradiol may be attributed to fluctuations in the free estradiol and to estradiol which is bound with low affinity to non-specific plasma proteins.

Estradiol↗
PubMed1976

Progesterone binding in rabbit oviduct and uterus.

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.

Animals↗
PubMed1975

Progesterone receptor of the human myometrium.

A progesterone binding protein was characterized in the cytosol of human myometrium. The receptor sedimented in the 4S region on sucrose gradients and had an equilibrium dissociation constant of 3.7 times 10-9M. Synthetic progestagens had an affinity equivalent to that of progesterone while cortisol had low affinity for the binding protein. These same progestagens showed very low binding to human CBG. In normally cycling women, the total levels of cytosol receptor were higher during the follicular phase than during the luteal phase. Subjects taking oral contraceptives and those who were pregnant had the lowest concentration of myometrial progesterone receptor. Postmenopausal women had levels of myometrial receptor lower than those of the secretory phase of the cycle. Estrogen therapy increased the receptor concentrations of the menopausal myometrium to those of the proliferative phase. The estradiol receptor levels of myometrial cytosol revealed similar changes in cycling women. When both binding proteins were measured concurrently in the same specimen, there was a significant positive correlation.

Anovulation↗
PubMed1975

Hormonal changes associated with Danazol therapy.

During a 6-month course of treatment of endometriosis with Danazol, a synthetic derivative of 17alpha-ethinyl testosterone, the following hormonal changes were found. Plasma LH remained essentially unchanged but FSH concentration was consistently in the low normal range. Plasma estradiol, especially after the fourth week of therapy, dropped to levels that did not exceed 30 pg/ml throughout the 6-month period of therapy. Plasma progesterone concentration was consistent with follicular phase levels. In the months after discontinuation of Danazol, all hormone parameters were strongly suggestive of normal ovulatory cycles. Danazol did not displace estradiol bound by endometrial cytosol.

Alkynes↗