Receptor-proteims for androgens and the mode of action of androgens on gene transcription in ventral prostate

Chick-comb fibroblasts. A new strain of cultured cells sensitive to androgens

An androgen-responsive cell strain of chick-comb fibroblasts has been established in culture. Cells were obtained from combs of 1--2 day old white Leghorn cockerels and cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal calf serum and 6 g/l glucose. The cells required serum but not androgens for growth. In the presence of androgens, growth rate and incorporation of labeled precursors into protein and RNA were markedly increased in exponentially growing cells, but not in confluent cultures. Androgens exerted these stimulatory effects in a dose-dependent fashion. It is concluded that chick-comb fibroblasts, which respond to androgens in vivo, retain this responsiveness when cultured. They furnish a well-defined system of potential value for studies of the molecular mechanisms of androgen action.

The rate of absorption into the embryonic chicken (Gallus domesticus) of 3H-testosterone

The maximum absorption of tritiated testosterone by 5-day old embryos occurred one hour after its application to the eggshell. This decreased to relatively low levels during a 77 hour period. When the hormone was applied at the eleventh day of incubation there was a relatively large initial uptake by the bursa, spleen and thymus in that order and a subsequent diminution. Activity absorbed by the spleen remained essentially unchanged throughout the experimental period. The bursa appeared to have the greatest affinity for the hormone.

Sex hormone binding globulin in carcinoma of the prostate

Sex Hormone Binding Globulin (SHBG) was measured in 130 patients with carcinoma of the prostate. Its level is raised in patients treated with oestrogen and it is possible that this may be of prognostic significance. The possible relevance of SHBG in oestrogen-treated patients is discussed.

Characterization and hormonal control of the androgen receptor in the hamster sebaceous glands

The costovertebral organs [CVO] and seminel vesicles [SV] of the hamster exhibit high saturable androgen uptake. The physicochemcal characteristics of the cytoplasmic androgen receptor present in these tissues have been determined and compared to those obtained in rat prostate[P]. Using the synthetic androgen R 1881 [methyltrienolone] as a radioactive ligand, it has been shown that the affinity of this compound for the cytosol CVO receptor [Kd = 0.7 +/- 0.1 nM] is similar to that for the crytosol SV receptor [Kd = 2.4 +/- 0.9 nm] in hamsters and the cytosol P receptor [Kd = 0.6 +/- 0.1 nM] in rats. The hormonal specificity of binding in these tissues is restricted to androgens. Moreover, testosterone and dihydrotestosterone have the same relative binding affinity in CVO and SV compared to R 1881. Following castration, the total number of androgen sites, as measured by an exchange assay with R 1881, decreases rapidly and parallels with a fall in lipogenic activity. Administration of an androgen rapidly restores binding capacity.

Deoxyribonucleic acid and polyamine synthesis in rat ventral prostrate. Effects of age of the intact rat and androgen stimulation of the castrated rat with testosterone, 5 alpha-dihydrotestosterone and 5 alpha-androstane-3 beta, 17 beta-diol

The relationship between polyamine synthesis, growth and secretion in vivo was examined in ventral prostates from: (a) intact rats aged 3-60 weeks; (b) animals castrated for 7 days before injection with 5 alpha-dihydrotestosterone (17 beta-hydroxy-5-alpha-androstan-3-one), testosterone and 5 alpha-androstane-3 beta, 17 beta-diol for up to 10 days; (c) rats injected with the 3 beta, 17 beta-diol immediately after castration. Ornithine decarboxylase activity and the concentrations of putrescine, spermidine and spermine were measured. DNA-synthetic activity was monitored by measuring [125I]iododoxyuridine incorporation. An enhanced spermidine/spermine molar ratio reflected increased activity of the prostate. The ratio was higher (greater than 2) in prostates from sexually immature animals, than in the intact adult (1.5), suggesting that the ratio was indicative of the proliferative activity of the tissue. However, in the androgen-stimulated castrated rat, enhanced spermidine/spermine ratios tended to correlate with hypertrophy and secretion. In both sets of experiments there was a linear relationship between protein and spermidine content. High spermidine/spermine molar ratios were the consequence of a relatively low rate of accumulation of spermine relative to spermidine and protein. The relationship between polyamine synthesis and DNA-synthetic activity was investigated in cultured prostate. A combination of insulin (3 mug/ml) and testosterone (0.1 muM caused a stimulatory response in the incorporation of [125I]iododeoxyuridine and in cell division, despite a depleted polyamine content and low ornithine decarboxylase activity in the cultured tissue.

Changed levels of endogenous sex steroids in women on oral contraceptives

Serum and urinary levels of unconjugated testosterone, dihydrotestosterone, and oestradiol were measured by specific radioimmunoassays in 10 healthy women in the early follicular phase of their menstrual cycle and in nine healthy women taking oral contraceptives. The contraceptive group had testosterone levels 1-3 times higher and dihydrotestosterone levels two times higher than those in the controls. Serum oestradiol levels in the contraceptive group were much lower than those in the controls and similar to levels in postmenopausal women. The contraceptive group had about twice the urinary excretion of unconjugated (free) testosterone and dihydrotestosterone of the controls, but their excretion of unconjugated oestradiol was 2-7 times lower. The great increase in serum and urinary androgen concentrations, as well as the suppression of oestradiol, may be related to the antiovulatory effect of oral contraceptives.

Binding of [3H] methyltrienolone (R 1881) in rat prostate and human benign prostatic hypertrophy (BPH)

Methyltrienolone (R 1881 - 17beta-hydroxy-17alpha-methyl-estra-4, 9, 11-trien-3-one) binding to rat ventral prostate cytosol has a specificity typical of an androgen receptor. In human benign prostatic hypertrophy (BPH) tissue, the specificity of [3H] R 1881 binding is different from that measured in rat prostate: progesterone and R 5020 (17, 21-dimethyl-19-nor-4, 9-pregnadiene-3, 20-dione) being more potent while 19-nortestosterone is less potent competitor. Moreover, the synthetic progestin [3H] R 5020 binds to BPH tissue with a similar specificity. These data suggest the presence of progestin binding components or of an atypical androgen receptor in human BPH cytosol.

Testicular chromatin activation in hypophysectomized rats

Incorporation of labeled thymidine into testicular DNA of hypophysectomized rats began to increase after the administration of testosterone propionate and choriogenic gonadotrophin. While the thymidine incorporation reached maximum in 4 days, the DNA polymerase activity did not culminate until 8 days after the initiation of hormone treatment. The high molecular weight (6--8 S), presumably cytoplasmic DNA polymerase accounted almost entirely for this increase. Administration of testosterone propionate and chorionic gonadotrophin to hypophysectomized rats results in an increase of testicular RNA polymerase and chromatin templating activity. Chain elongation and initiation studies revealed that the increased templating capacity of androgen-stimulated testicular chromatin was almost entirely caused by the increase in the number of initiation sites. While the nuclear polymerase I responded relatively rapidly to hormone stimulation and reached a prominent maximum in about three days, the activity of polymerase II was more sluggish and not as prominent. The in vivo incorporation of ortho[32P]phosphate into chromosomal phosphoproteins occurred early during the androgen treatment and reached a maximum in about 20 h. The protein phosphokinase activity peaked later, approx. 72 h after the first administration of hormones.

The effects of testosterone, 5alpha-dihydrotestosterone, 3alpha-androstanediol, and 3beta-androstanediol on the maturation of rabbit epididymal spermatozoa in organ culture

The fertilizing ability of spermatozoa from epididymal tubules maintained in organ cultures from 1 to 7 days was assessed after artificial insemination into receptive does. It was found that spermatozoa from the distal corpus which were already capable of fertilizing eggs prior to the cultures retain this ability for 1 day without addition of hormone and for 3-4 days when testosterone (0.5 mug/ml) or 5alpha-dihydrotestosterone (0.5 mug/ml) is added to the culture medium. Spermatozoa from the proximal corpus which were not capable of fertilizing eggs prior to the cultures remain so after 1 day in cultures without addition of hormone. Testosterone, 5alpha-dihydrotesterone, 3alpha-androstanediol, or 3beta-androstanediol was added to cultures of proximal corpus at a concentration of 0.5 mug/ml. Only with 5alpha-DHT is the mean percentage of fertilization significantly higher than the percentage obtained without addition of hormone. Insulin does not potentiate the effect of 5alpha-DHT on sperm fertilizing ability. Epithelial growth factor is ineffective. Spermatozoa from the caput epididymidis kept in cultures for 1 to 4 days remain infertile. The results are discussed in light of the morphological findings presented in the preceding communication and in relation to the physiological requirement for sperm maturation in the epididymis.

An androgen receptor in rat brain and pituitary

Dihydrotestosterone (DHT) binding was measured in cytosols from brain regions and pituitary of adult female rats and, with the addition of ventral prostate, in adult male rats. Two types of binding were distinguished: one, saturable at concentration of DHT greater than or equal to 5 X 10(-9) M and an unsaturable component. In intact males saturable (limited capacity) binding was detected only in ventral prostate cytosol; 3 days after orchidectomy the saturable binding sites increase 3-fold in prostate and in pituitary, hypothalamus, amygdala and cortex to detectable levels in approximately the same abundance as in females. There were significant differences in the affinities of the limited capacity binding reactions in cytosols of different tissues though all were in the order of magnitude, 10(-9) M DHT. The affinity in pituitary cytosol was lower than in brain regions with the single exception of female amygdala in which the affinity was significantly lower than in cytosol of the same region from 3-day castrate males. The specificity of the limited capacity binding was investigated by competition between [3h]DHT and unlabelled steroids; the most effective competitors were potent androgen agonists and antagonists.

The androgenic regulation of the activities of enzymes engaged in the synthesis of deoxyribonucleic acid in rat ventral prostate gland

The restoration of mitosis and growth of the prostate gland of castrated animals by androgens provides a favourable experimental system for studying the hormonal regulation of enzymes engaged in DNA replication. 2. Many DNA polymerase activities were identified in the prostate gland, but only a 9S form with a particular preference for denatured DNA as template was conspicuously enhanced by androgenic stimulation. 3. Thymidine kinase also provided a sensitive indicator of the hormonal regulation of DNA replication, and on electrophoretic criteria, one discrete form of the enzyme appeared precisely with the onset of mitoris. 4. Evidence is presented to support the view that DNA ligase activity is intimately associated in the process of DNA replication in the prostate gland. 5. A spectrum of deoxyribonuclease activities is present in the prostate gland, but only one form (pI7.0) can safely be said to be implicated in the process of DNA replication. 6. Androgenic stimulation of the prostate gland leads to the appearance of a component capable of denaturing or unwinding prostate DNA. This component is seemingly distinct from RNA or DNA polymerase activities on the basis of several distince physicochemical characteristics. 7. The conspicuous feature of all the changes in enzyme activities evoked by androgens in the prostate gland is their acute tissue- and steroid-specificity. Such changes could not be mimicked in liver or spleen and the regulatory role of androgens could not be simulated by other classes of steroid hormones. Particularly on the basis of studies with the anti-androgen cyproterone acetate, it is concluded that the changes are initially mediated by the androgen-receptor system and the high-affinity binding of 5alpha-dihydrotestosterone in the prostate gland. 8. The results are discussed in the context of the mechanism of action of androgens.

How specific are nuclear "receptors" for thyroid hormones?

The presence of "high-affinity-saturable" binding sites for thyroid hormones of similar characteristics not only in isolated nuclei but in all the major extranuclear cellular components, as well as the failure of cytosol to promote nuclear binding, invalidates the analogy with steroid hormone receptors and necessitates a more critical assessment of the physiological relevance of current approaches to binding of thyroid hormone in vitro nuclear preparations.

Methyltrienolone, a specific ligand for cellular androgen receptors

Methyltrienolone (R 1881), 17beta-hydroxy-17alpha-methyl-estra-4,9,11-trien-3-one, a very active androgen, binds specifically to rat prostate cytosol with a higher affinity than androstanolone. Unlike the physiological hormone, however, it is not bound by human sex steroid plasma binding protein, SBP. This specific ligand is thus a useful tool for the detection of elusive androgen receptors and for their study, for instance, in human tumors where interference from plasma contamination has to be circumvented.

Demonstration and partial characterization of cytosol receptors for testosterone

Androgen uptake was investigated in several peripheral organs after administration of (1,2,6,7 minus -3H)testosterone to castrated male rats. The animals were killed after 30 min, the organs were taken out, and the radioactivity was determined after tissue combustion. A relatively high accumulation of androgen was found in pancreas, adrenals, spleen, thigh muscle, kidneys, and liver in addition to the classical androgen target organs coagulation glands, seminal vesicles, prostate, preputial glands, and harderian glands. In a second serier of experiments, nuclear and cytosol fractions were prepared from prostate, seminal vesicles, coagulation glands, preputial glands, spleen, submaxillary glands, kidneys, and pancreas from castrated male rats give (1,2,6,7 minus -3H)testosterone, and these fractions were then characterized by thin-layer and radio-gas chromatography with respect to their patterns of labeled steroids. Only prostate and seminal vesicles were found to contain significant amounts of nuclear 5alpha-(-3H)dihydrotestosterone. The major nuclear androgen was (-3H)testosterone that was the only detectable labeled steroid in coagulation glands, preputial glands, and spleen and that constituted 70% or more of the nuclear radioactivity in seminal vesicles, submaxillary glands, kidneys, and pancreas. These results indicate that testosterone itself may be the predominant active androgen principle in vivo in most androgen target organs and that conversion to 5alpha-dihydrotestosterone is generally not a prerequisite for androgen activity. Using an ultrasensitive micromodification of isoelectric focusing (cf. M. Katsumata and A. S. Goldman (1974), Biochem. Biophys. Acta 359, 112. It was possible to show that cytosol from kidney; submaxillary gland, thigh muscle, and levator ani muscle and nuclei from kidney and submaxillary gland contained androgen-binding proteins with pI's in the region 4.6-5.1 ("4.6 minus 5.1 Complex"). This complex also formed in vitro after incubation of (1,2,6,7 minus -3H)testosterone with cytosol from kidney and submaxillary gland. (1,2,6,7 minus -3H)Testosterone was bound with high affinity to receptor proteins in cytosol from both kidney, submaxillary gland, and thigh muscle with dissociation constants of 5.0 x 10 minus -12 M (kidney), 3.3 x 10 mi;nus -11 M and 4.1 x 10 minus -10 M (two types of binding sites, submaxillary gland), 2.4 x 10 minus -12 M (thigh muscle) and 1.9 x 10 minus -12 M (levator ani muscle). The number of binding sites was in all cases between 1 and 20 fmol/mg of protein. On the basis of these results the hypothesis is presented that a common class of testosterone receptors is present in most organs and that these receptors can be detected both in vivo and in vitro provided methods sensitive enough are utilized.

Effect of gonadal hormones on enzyme activities in brain and pituitary of male and female rats

Gonadectomized male and female rats were treated with equimolar doses of estradiol benzoate (EB) or testosterone pripionate (TP) daily for one week and enzyme activities were measured in the basomedial hypothalamus, corticomedial amygdala, and pituitary. In females, the hypothalamus showed estrogen-dependent increases in glucose-6-phosphate dehydrogenase (G6PDH), isocitrate dehydrogenase (ICDH), and malate dehydrogenase (MDH). Activities of ICDH and MDH were elevated in the amygdala. In the pituitary, estrogen administration resulted in increased levels of G6PDH, 6-phosphogluconate dehydrogenase (6PGDH), and lactic dehydrogenase (LDH). The estrogen antagonist, MER-25, effectively blocked estrogen-dependent increases in pituitary G6PDH and 6PGDH. Administration of TP did not result in changed enzyme levels. In males, treatment with EB and TP resulted in significant elevations in some but not all enzymes that were increased by EB in the female. Estrogen-dependent increases of activity in males were noted in pituitary G6PDH, 6PGDH, and LDH, in hypothalamic MDH, and in amygdaloid ICDH. Administration of TP led to increased levels of pituitary G6PDH, 6PGDH, LDH, ICDH, and MDH, hypothalamic ICDH and G6PDH, and amygdaloid MDH. The pattern of enzyme changes found in male and female brain and pituitary is discussed in relation to behavioral responses to gonadal hormones, nuclear uptake of gonadal hormones, and metabolism of androgen.

A very rapid effect of androgen on initiation of protein synthesis in prostate

The initiation of protein synthesis by ribosomal particles of rat ventral prostate was studied by measuring ribosomal binding of an initiator (35-S)methionyl-tRNAf. The binding activity is dependent on ribosomes, GTP, and a prostate cytosol protein fraction. The 40S but not the 60S ribosomal subunit particles are active. The cytosol activity decreases rapidly within one hour after the rat is castrated. This loss is prevented by an intraperitoneal injection of 17beta-hydroxy-5-alpha-androstan-3-one (5-alpha-dihydrotestosterone). The cytosol activity can be stimulated almost immediately (within 10 min) after an intravenous injection of low dose (15 mug per rat) of 5-alpha-dihydrotestosterone into the castrated rat.

In vivo androgen retention in mouse kidney

The in vivo retention of 3-H-testosterone, dihydrotestosterone (DHT), 3alpha-androstanediol (3alpha-DIOL), 3beta-DIOL, androstenedione, progesterone and cortisol by renal cytoplasm and nuclei of male and female mice was studied. Testosterone was the major androgen isolated from cytoplasm and nuclei following testosterone or androstenedione administration. By contrast, DHT was the major intracellular androgen after DHT, 3alpha- or 3beta-DIOL injection. The uptake of 3-H-testosterone or 3-H-DHT was abolished by excess unlabeled testosterone, DHT or cyproterone acetate. Androgen concentrations in kidney fractions from female mice were similar to those from males. There was no appreciable concentration of the isolated steroids following 3-H-progesterone administration. 3H-cortisol was concentrated in both cytoplasm and nuclei but was not displaced by non-radioactive androgens. These findings suggest that in contrast to prostate, mouse kidney can concentrate both testosterone and DHT. However, since testosterone is the major androgen in blood and since it is not metabolized in kidney, it is the major effector androgen in this organ. Androstenedione is active via conversion to testosterone while DIOLS are androgenic via metabolism to DHT.

[Esterase XX. Disc-electrophoretic investigations on the polymorphism of the esterases of the house mouse (author's transl)]

For the further clarification of the polymorphism of mouse-esterase and its hormonal control, which in part have not yet been fully comprehended, disc-electrophoretic analyses of eight organs were made, using a strain with the Tfm-mutation. In addition, quantitative assays of esterase activity as well as histochemical studies were performed. The individual organs are characterized by a specific banding pattern of esterase, which is essentially conditioned by the diverse activity of a limited number of bands. Partly these may be regarded as primary gene products, partly they seem to be secondary modifications. The few incidences of band-linkage justify the expectations, that further gene loci will be discovered. In four organs of Tfm-mutants a lower esterase activity was found than in the controls, which was especially distinct in the kidney. The behaviour of the testosterone-dependent bands in the kidneys of Tfm-mutants seems to indicate two different mechanisms of the effect of testosterone on these bands.