The role of thyroxine (T4)-binding serum proteins in oleic acid-induced increase in free T4 in nonthyroidal illnesses

We studied the effects of various concentrations of oleic acid (0.1-3.3 mM), such as are often found in the serum of patients with nonthyroidal illness, on the dialyzable (free) fraction of T4 (DFT4) in three types of serum samples: pooled normal serum (PNS), pooled pregnancy serum (PPS), and pooled serum of hospitalized patients (PSHP). The samples were extracted with diethyl ether to remove endogenous fatty acids before being tested in the DFT4 assay. Oleic acid caused only a moderate increase in DFT4 in PNS; a significant (greater than 2 SD above control) increase (15%) was found with 2.0 mM oleic acid, and the maximal dose of oleic acid (3.3 mM) caused a 33% increase in DFT4. However, the DFT4-increasing effect of oleic acid was enhanced (increase in DFT4 of 33% caused by 0.9-1.2 mM oleic acid) when the serum tested had low (0.5 times normal) albumin and prealbumin concentrations with either normal (50% PPS) or half-normal TBG (50% PNS). The effect of oleic acid in 100% PSHP was significantly (P less than 0.005) greater than that in 100% PNS, and it was close to that in 50% PNS (increase in DFT4 with 3.3 mM oleic acid, 118% in PSHP vs. 98% in 50% PNS). Normalization of serum albumin in PSHP by adding exogenous albumin markedly reduced the DFT4-increasing effect of oleic acid; the maximal increase in DFT4 of 64% with 3.3 mM oleic acid in albumin-normalized PSHP was equalled with 1.3 mM oleic acid in unmodified PSHP. The data suggest that the serum concentrations of albumin and other T4-binding proteins are important in modulating the DFT4-increasing effect of oleic acid and that oleic acid may contribute to the reduced serum binding of T4 in nonthyroidal illness.

Serum bioavailability and tissue metabolism of testosterone and estradiol in rat salivary gland

The concentration of testosterone in saliva is probably in equilibrium with the concentration of cellular exchangeable testosterone in salivary gland, and these pools are a function of hormone transplant from the plasma compartment, and hormone metabolism in salivary gland cells. Both of these processes were examined in the present study using the carotid injection technique in normal and pilocarpine-stimulated ketamine-anesthetized rats. Both testosterone and estradiol were rapidly transported across salivary gland capillaries in vivo from the circulating albumin-bound pool. Estradiol, but not testosterone, was also rapidly transported into salivary gland from the circulating human sex hormone-binding globulin-bound pool. Hormone transport was several-fold greater than the capillary transport of [3H]bovine albumin, indicating that bound hormone was available for transport across salivary gland capillaries via an enhanced dissociation mechanism, with the plasma protein primarily residing in the plasma compartment. This result was confirmed by thaw-mount autoradiography, which showed diffuse distribution of [3H]testosterone in salivary gland, but vascular retention of [3H]bovine albumin. The concentration of exchangeable cellular testosterone in rat saliva was less than 4% of the total or plasma exchangeable testosterone in the rat. This marked discrepancy between the concentration of plasma and cellular exchangeable hormone suggested that there was rapid metabolism of androgen by salivary gland in vivo. This was confirmed by chromatographic separation of [3H] testosterone and labeled metabolites in homogenates of salivary gland. By 60 sec after injection, approximately 30% of the radioactivity in the salivary gland was in the form of androgen metabolites, which primarily comigrated with an androstenedione standard. The data indicate that albumin-bound testosterone, albumin-bound estradiol, and sex hormone-binding globulin-bound estradiol are all exchangeable in salivary gland capillaries. The low concentration of cellular exchangeable testosterone in salivary gland appears to be due to rapid tissue metabolism of this hormone. Thus, changes in androgen metabolism may alter salivary gland hormone concentrations independent of any change in the concentration of biologically active hormone in plasma.

Enhanced hepatic extraction of estrogens used for replacement therapy

Oral estrogen administration elicits greater effects on hepatic than on nonhepatic markers of estrogen action. This has important clinical implications, since the hepatic actions of estrogens are believed to account for several complications of this form of therapy. To date, the mechanism responsible has been attributed to the so-called first pass effect of the orally administered hormones. The present study was undertaken to examine the in vivo extraction from the circulation of all commercially available classes of estrogens used for replacement therapy. Influxes from the microcirculation into three important target organs of estrogen action, i.e. the brain, uterus, and liver, were assessed. This was accomplished by the use of previously described double isotope, single injection, timed tissue-sampling techniques. For the brain, two patterns of influx were found using different injection vehicles. The first was characterized by high extraction (80-100%) in the absence of plasma proteins. The only inhibitory effects on influx were exerted by plasma proteins. Estrogens displaying this pattern were estradiol, estrone, and ethinyl estradiol. The second pattern was characterized by very restricted influx in the absence of plasma proteins, and plasma protein binding had little or no additional effect. In the absence of plasma proteins, the percentages extracted of estrone sulfate (E1S) and diethylstilbestrol were 6.5% and 38.5%, respectively. For the uterus, the patterns of extraction of all five estrogens were similar to those found for the brain. In contrast, the hepatic microvasculature was freely permeable to all estrogens including E1S and diethylstilbestrol. Albumin binding had little or no effect on hepatic uptake. Significant reductions in the influx of estradiol and E1S were found only when the injection vehicle was human pregnancy serum (high sex hormone-binding globulin concentration). In the presence of plasma proteins, the hepatic extraction of all of the estrogens studied significantly exceeded that in the brain and uterus. We conclude that enhanced delivery of circulating estrogens to the liver compared to that to the brain and uterus provides a further explanation for the enhanced hepatic actions of these preparations when used for oral replacement therapy.

Inhibition by indomethacin of increased estradiol extraction by the IUD-containing rat uterine horn

The role of prostaglandins on the extraction of estradiol (E2) by the rat uterine horn in the presence of the intrauterine device (IUD) was evaluated. Increased extraction of E2 by the IUD horn compared to the contralateral control horn was consistently observed irrespective of the estrogen status of the animals. This increased extraction was abolished by indomethacin, an inhibitor of prostaglandin synthesis, suggesting a role of prostaglandin in this process.

Differential permeability of uterine and liver vascular beds to estrogens and estrogen conjugates

The role of capillary membrane permeability and the effect of plasma protein binding on the influx of unconjugated and conjugated estrogens into a target organ, the uterus, and a metabolic organ, the liver, were studied in anesthetized rats. In the absence of plasma proteins, estrone (E1) and estradiol (E2) were freely diffusible through the uterine capillaries, but influx was significantly reduced for estriol (E3) and estetrol. In the uterus, the influx of the conjugated estrogens was markedly restricted and approximated the influx of dextran, a vascular space marker. The polarity of the compound (based on the number of hydrogen bond-forming functional groups and the presence of charged groups) appeared to predict uterine endothelial membrane permeability better than the octanol/Ringer's partition coefficient. In contrast to the selective permeability properties of the uterine endothelial barrier, the limiting membrane lining the hepatic microcirculation, the hepatocyte cell membrane, was highly permeable to all unconjugated and conjugated estrogens. The addition of 4% albumin to the injection solution led to a significant inhibition of uterine influx of E2, but not E1 or E3. In the liver, only the influx of E1 sulfate was slightly diminished by 4% albumin. In all cases, the influx of estrogens greatly exceeded the rate that would be expected if only the fraction that was free (dialyzable) in vitro was diffusible in vivo. Human sera containing sex hormone-binding globulin and albumin caused inhibition of influx of E1 and E2 through the uterine capillary barriers, whereas in the liver, the influx of E2 sulfate, and E3 glucuronide were diminished. The results are compatible with a difference in permeability of the microvasculature of the two organs and a differential availability of protein-bound estrogen for influx into liver and uterus. With the exception of E1, which is nearly completely diffusible into both organs, the influx of estrogens and estrogen conjugates into liver is greatly amplified compared to that into a peripheral organ such as the uterus.

The effect of membrane permeability and binding by human serum proteins on sex steroid influx into the uterus

To determine the effect of such factors as capillary membrane permeability, plasma protein binding, and capillary transit time on the availability of sex steroids to the uterus, the unidirectional influxes of 3H-labeled steroids from the circulation into the uterus were measured in vivo in anesthetized rats using a tissue-sampling, single injection technique. When dihydrotestosterone (DHT), estradiol (E2), and progesterone (P) were injected with Ringer's solution, the tissue extraction was in excess of 80%; hence, membrane permeability did not play a limiting role. With the more polar steroids, corticosterone and cortisol, uterine extraction was less than 40%. Significant inhibition of tissue extraction of DHT and E2, but not P, occurred with the addition of 4% albumin to the injection solution. Human sera containing increasing concentrations of sex hormone-binding globulin demonstrated inhibition of extraction of DHT and E2. Human sera also inhibited P extraction, presumably secondary to the presence of cortisol-binding globulin and orosomucoid. Large concentrations of unlabeled DHT, E2, and P in the injection solutions did not result in competitive inhibition of labeled steroid extraction. Thus, there is no evidence for a carrier mechanism mediating steroid transport into the uterus. When tissue extraction of E2 from Ringer's solution was compared in liver, brain, and uterus, no difference of tissue permeability could be found. Liver consistently had higher tissue E2 extraction than brain or uterus in the presence of human sera. The results are compatible with the influx of albumin-bound E2 into all three tissues and the influx of sex hormone-binding globulin-bound E2 into the liver.

A specific and sensitive radioimmunoassay for human choriogonadotropin

A specific and sensitive radioimmunoassay for human choriogonadotropin (hCG) has been developed using rabbit antiserum to chemical analogs of beta subunit of human chorionic gonadotropin prepared by controlled reduction and S-alkylation of its disulfide linkages. The assay was highly specific for hCG as the binding of [125I]-hCG to the antibody was not affected by standard human lutropin, by human male serum, postpartum serum from women, serum from post-menopausal women and human menopausal gonadotropin (Pergonal). The assay was highly sensitive, the minimal detection limit in terms of highly purified hCG (L-129, 12500 IU/mg) being 1 ng/ml or 0.2 ng/tube (or 12 mlU/ml in terms of WHO 2nd international reference preparation of hCG). Using this assay we were unable to detect any immunoreactive hCG in human tissues like lung, liver and colon. The high specificity, sensitivity, accuracy and reproducibility of the assay make this a highly desirable radioimmunoassay for human choriogonadotropin.

Uterine and peripheral blood concentrations of vasodilator prostaglandins in conscious pregnant rabbits

The concentrations of prostaglandin E2 (PGE2) and prostacyclin (PGI2) were estimated in blood obtained from the uterine venous effluent and a peripheral artery of conscious pregnant and nonpregnant rabbits. The blood was analyzed both with a superfusion bioassay and radioimmunoassays. PGE2, but not PGI2, was detected in a very high concentration in the uterine venous effluent of the pregnant rabbit. The peripheral blood of pregnant animals also revealed increased levels of only PGE2. The results of both assay techniques correlated closely. These studies suggest that the uteroplacental unit is the source of the increased peripheral level of the potent vasodilator PGE2. In contrast, these data fail to support the notion that PGI2 is the primary systemic-acting vasodepressor prostaglandin in rabbit pregnancy.

Management of a vaginal foreign body

A case is presented of a vaginal foreign body. A drinking glass was inserted in the vagina of an intoxicated patient by her irate lover. Infection followed. The emergency care is described, including the method of extraction of the object, along with discussion of the principles involved and associated complications.

Effect of an intra-uterine device on intracellular relationships of the uterine oestrogen receptor, particularly during pregnancy

The presence of an intra-uterine device in the rat results in a lower nuclear concentration of the oestrogen receptor in the treated horn at pro-oestrus when it is compared with the contralateral control horn. This effect was also seen after the administration of hyperphysiological doses of oestradiol and when the horn was exposed in vitro to high concentrations of oestradiol. The cyclic changes during the oestrous cycle in the activity of the oestrogen-induced enzyme peroxidase were similar in the treated and control horns. These observations have discounted the possibility that the relatively lower nuclear receptor content in the treated horn at pro-oestrus was due to a decreased exposure to oestrogen. A significantly lower nuclear content was also observed in the treated horn on days 4 and 5 of pregnancy. This was not associated with a deficiency in cytosol receptor content which increased concurrently with that of the control horn in the 6 days of pregnancy that were studied. The proportional content of the putative cytosol factor implicated in receptor translocation was similar in both horns, increasing on days 4 and 6 in concert with reported changes in 'induced protein' synthesis. There appeared to be reduced levels of nuclear receptor at a time when blastocyst implantation normally occurs.

The oestrogen receptor in the rat uterus in relation to intra-uterine devices and the oestrous cycle

We investigated the binding characteristics, content and intracellular distribution of nuclear and cytosolic oestrogen receptors in the uteri of rats bearing a unilateral intrauterine device, fitted 14--18 days earlier, at four phases of a 5-day oestrous cycle. The patterns of changes in wet weight and content of cytosolic and nuclear receptor that normally occur during the oestrous cycle were not altered by the presence of the device. At all stages of the cycle the intra-uterine-device-containing horn had a greater wet weight and a correspondingly higher content of cytosolic receptor than its contralateral control horn, the cellular concentration of cytosolic receptor being apparently maintained. However, the intra-uterine-device-containing horn had significantly lower cellular concentrations (i.e. per mg of DNA) of nuclear receptor, particularly at late dioestrus and pro-oestrus. Thus the treated horn showed a decreased translocation of receptor in response to increases in circulating oestrogens. Both horns contained equivalent amounts of an activating factor implicated in translocation and measured in vitro by binding of cytosol receptor to oligo(dT)-cellulose. The presence of an intra-uterine device neither altered the dissociation constants (Kd) of the nuclear and cytosolic oestrogen-receptor complexes nor the stability of the nuclear receptor complex in vitro. The decreased translocation cannot thus be directly attributed to changes in the physical properties of the receptor. This decrease may be responsible for the anti-fertility effect of the intra-uterine device (which affects only the treated horn of the bicornuate rat uterus), since implantation of the blastocyst requires correct concentrations of nuclear oestrogen receptor.

The role of prostaglandins in the spontaneous motility of the fallopian tube

Spontaneous isometric contractions of the human fallopian tube were measured in vitro. The tubes were obtained during the follicular phase of the menstrual cycle in 16 experiments and during the luteal phase in 23 experiments. The area under the curve and the frequency of spontaneous isometric contractions, together with the amount of prostaglandins E and F produced by the tube, were measured. Using each tissue as its own control, the effects of adding indomethacin or papeverine to the tissue both were assessed. Indomethacin, a prostaglandin synthetase inhibitor, significantly reduced the prostaglandin output without affecting the tubal motility. By contrast, papaverine, which is a smooth muscle relaxant but not an inhibitor of prostaglandin synthesis, significantly reduced both motility and prostaglandin output. It is concluded that prostaglandins do not have a direct role in the regulation of the spontaneous motility of the human fallopian tube.

Lack of evidence for inhibition of ovulation by aspirin in women

Prostaglandin synthetase inhibitors such as aspirin and indomethacin inhibit ovulation in experimental animals. The effect of therapeutic doses of aspirin on ovulation has been studied in 5 women. Ovulation, as assessed by measurements of urinary LH and plasma progesterone levels, basal body temperature and cervical mucus changes occured in all the control and treatment cycles. Serial sections of the corpora lutea failed to show any entrapped ova. The significance of finding a prostaglandin synthetase inhibitor which acts specifically at the ovarian level is discussed.

Inhibition by aspirin and indomethacin of uterine hypertrophy induced by an IUD

An IUD inserted into one uterine horn caused an increase in its weight when this was compared with that of the contralateral control horn in rats. Such an increase could be partly prevented by treating the animals with indomethacin and aspirin. It is suggested that the IUD-induced increase in weight is at least in part mediated by release of prostaglandins.