Radioimmunoassay of progesterone, 17-hydroxyprogesterone, estradiol-17beta and prostaglandin F in human corpus luteum.

Radioimmunoassay procedures have been adapted for the assay of progesterone, 17-hydroxyprogesterone, estradiol-17beta, and prostaglandin F in human corpus luteum. The method utilises a single homogenisation and extraction of the tissue followed by fractionation of the steroids on alumina, and separation of the prostaglandins of the F series from the E and A series on silica gel, prior to radioimmunoassay. An attempt has been made to validate the method for the progestins by comparison with results after fractionation of the progestins on Sephadex LH-20, for estradiol-17beta by comparison with values obtained with competitive protein-binding, and for prostaglandin F by comparison with values after additional purification. The results showed that peak concentrations of the three steroids in corpora lutea from women during the luteal phase of the menstrual cycle were comparable to those found in corpora lutea from women in early pregnancy. However, in six out of fourteen corpora lutea from non-pregnant women, prostaglandin F levels were higher than those found in corpora lutea from seven women in early pregnancy, i.e. 13-46 ng/g compared with 1-7 ng/g. Of the above six corpora lutea, four were on days 23-25 of the cycle, at a time when luteolysis would be commencing. The results in this paper support the conclusion that the corpus luteum is a major site of synthesis of the three steroids examined, although the site of synthesis of prostaglandin F is still equivocal.     

Concentrations of unconjugated 5 alpha-androstane-3 alpha, 17 beta-diol and 5 alpha-androstane-3 beta, 17 beta-diol and their precursor in human testicular tissue. Comparison with testosterone, 5 alpha-dihydrotestosterone, estradiol-17 beta, and with steroid concentrations in human epididymis

The concentrations of testosterone and its tissular metabolites were determined in testicular and epididymal tissue obtained from eleven male subjects (aged 65-85 years) after orchiectomy for prostatic cancer. The steroids were measured in different tissular compartments, i.e. testis, caput, corpus and cauda epididymis. The values (mean +/- SD; ng/g wet weight) were: Testosterone 724.0 +/- 286.0, 32.08 +/- 2.56, 41.45 +/- 1.77 and 32.24 +/- 2.14; 5 alpha-dihydrotestosterone 6.95 +/- 1.99, 9.76 +/- 2.33, 16.87 +/- 0.21 and 15.79 +/- 2.67; 5 alpha-androstane-3 alpha, 17 beta-diol 6.07 +/- 2.33, 2.17 +/- 0.24, 1.93 +/- 0.02 and 1.17 +/- 0.20; 5 alpha-androstane-3 beta, 17 beta-diol 56.66 +/- 20.97, 3.55 +/- 0.19, 2.21 +/- 0.27 and 3.34 +/- 0.32; estradiol-17 beta 5.36 +/- 3.0, 1.08 +/- 0.014, 1.44 +/- 0.038 and 1.47 +/- 0.03, respectively. Incubation of human testicular tissue with [3H]androst-5-ene-3 beta, 17 beta-diol or [3H]dihydrotestosterone showed that both androstane-diols were exclusively formed from dihydrotestosterone. Since high concentrations of 5 alpha-androstane-3 beta, 17 beta-diol are found in testicular tissue it is suggested that this steroid may be an index of seminiferous tubular function.     

The effect of cortisol on the synthesis of prostaglandins (PGF2 alpha, PGE2) by human endometrial fibroblasts in vitro with and without addition of estradiol-17 beta or progesterone

Cortisol is known as a potent inhibitor of phospholipase A2 activity in several tissues. In fibroblast monolayer cell cultures from proliferative human endometrium cortisol alone does not affect the basal PGF2 alpha or PGE2 synthesis. After stimulation of PGF2 alpha production by 10(-7) mol/l estradiol-17 beta increasing concentrations of cortisol up to 10(-5) mol/l dosedependently reduce the PGF2 alpha production. Also the progesterone (10(-4) mol/l) stimulated increase of PGF2 alpha and PGE2 synthesis is inhibited by cortisol (10(-7) mol/l).     

The effect of clomiphene on the synthesis of prostaglandins (PGF2 alpha, PGE2, PGI2) in human endometrial cells in vitro with and without addition of estradiol-17 beta or progesterone

The production of prostaglandin F2 alpha in monolayer stromal cell cultures of proliferative human endometrium is enhanced by 10(-7) mol/l estradiol-17 beta or 10(-4) mol/l progesterone. Progesterone in high concentration (10(-4) mol/l) also enhanced the synthesis of prostaglandin E2. Clomiphene citrate reduced this increased prostaglandin production dose dependently. The synthesis of prostaglandin I2 was not influenced either by sex steroids or by clomiphene citrate.     

Uptake, distribution and binding of vertebrate and invertebrate steroid hormones and time-dependence of ponasterone A binding in Calliphora vicina. Comparisons among cholesterol, corticosterone, cortisol, dexamethasone, 5 alpha-dihydrotestosterone, 1,25-dihydroxyvitamin D3, ecdysone, estradiol-17 beta, ponasterone A, progesterone, and testosterone.

The presence of specific binding sites for radiolabelled vertebrate-type and arthropod-type steroid hormones was investigated in several organs including salivary gland, and central nervous system of third instar Calliphora vicina larvae by thaw-mount autoradiography. Ponasterone A, a 20-hydroxyecdysone agonist and 20-hydroxyecdysone are the only steroids which bind to nuclear high affinity binding sites. These binding sites are DNA associated while nucleoli show no tracer binding. Ecdysone, an endogenous 20-hydroxyecdysone precursor, is taken up by target cells but no significant nuclear binding occurs. 1,25-Dihydroxyvitamin D3 concentrates in cytoplasm only and its uptake is highest compared to all other steroids. Progesterone and testosterone show weak accumulation in the cytoplasm, while for cholesterol, corticosterone, cortisol, dexamethasone, dihydrotestosterone and estradiol-17 beta, no noticeable uptake occurs. For ponasterone A, a clear time dependence of uptake and intracellular distribution is visible, suggesting the existence and involvement of specific ecdysteroid uptake and transport mechanisms. These results suggest the presence of binding sites for various mammalian steroids in insects. Whether vertebrate steroid hormones or metabolites of them play a role in insects or whether the uptake and binding is based on chemical similarities alone without biological significance remains to be further investigated.