The effects of immunization against luteinizing hormone-releasing hormone on performance, sexual development, and levels of boar taint-related compounds in intact male pigs.

The effect of a newly developed anti-LH-RH vaccine on the performance, sexual development, and incidence of boar taint-related compounds was investigated in young intact male pigs. At 29 kg BW, 40 crossbred intact males and 20 castrates were allocated to three groups. Castrates and half of the intact males were untreated. The remaining intact males were immunized against LH-RH at 29 kg and again at 89 kg BW. All pigs were slaughtered at 105 kg BW. Compared with control intact males, feed efficiency in castrates was decreased by 10%, muscle content was reduced by 5%, and carcass fat content was increased by 26%. Growth performance and carcass traits did not differ significantly between immunized and control intact males. Genital tract weight, measured at slaughter, was decreased (P < or = .002) by immunization. Plasma testosterone concentrations were not significantly affected at 89 kg BW, whereas they were sevenfold lower (P < .001) in immunized than in control intact males at 105 kg BW. Fat androsterone levels, measured at slaughter, were substantially reduced (P < .001) from .66 +/- .07 microgram/g in control to .21 +/- .01 microgram/g in immunized intact males. Rates of testicular steroid biosynthesis, measured in vitro, were decreased by immunocastration. Fat skatole levels were very low and did not differ significantly between the three groups. The present results demonstrate that anti-LHRH immunization was effective in reducing the level of androstenone, a boar taint-related compound, although having a limited effect on the performance of the animals.

Are antibodies responsible for a decreased superovulatory response in goats which have been treated repeatedly with porcine follicle-stimulating hormone?

Repeated administration of xenogenic gonadotropins in human or animal species may be responsible for antibody production and refractoriness. An experiment was conducted in which goats were treated with porcine FSH (p-FSH) at 6-week intervals for a period of 7 months. A sensitive radioimmunoassay (RIA) was used to detect antibodies to p-FSH in plasma samples taken at short-term intervals during a 7-month period. Antibodies appeared after the first injection, and levels increased following booster injections. A high correlation rate existed between antibody level and superovulatory response. Refractoriness in goats was associated with a high level of antibodies.

Growth inhibitory effect of 4-hydroxy-tamoxifen on the BT-20 mammary cancer cell line.

The antiestrogenic activities of Tamoxifen have been well documented and this molecule has been successfully used in the treatment of hormone dependent breast cancer. In the present experiments we demonstrate that 4-hydroxy-Tamoxifen (OH-TAM) is able to reduce the growth of the BT-20 cell line which is devoid of estrogen and progesterone receptors. Various parameters have been investigated in growth studies under control conditions and in the presence of OH-TAM. Cell numerations, [3H]thymidine incorporation per cell or per microgram of DNA have shown that OH-TAM reduces the growth rate in proportion to its concentration from 10(-9) M to 10(-6) M. This activity is not reversed by estradiol addition. It is unaffected by the presence or the absence of Phenol Red in the medium. Analysis by flow cytometry suggests that it takes place before the S phase of the cycle. Examination of control and treated cells by Electron Microscopy shows no sign of toxicity. The growth inhibitory activity of OH-TAM on these cell lines appears therefore unrelated to its antiestrogenic properties.

Flow cytometry analysis of the growth inhibitory effect of 4-hydroxy-tamoxifen on a human breast carcinoma cell line.

Growth kinetics of BT-20 cells (an ER- cell line) have been studied with flow cytometry, cell counting and 3H-thymidine incorporation. The cell cycle lasts about 40 hours, with a maximum SG2M about 25h after seeding. 4-Hydroxy-tamoxifen (OH-Tamoxifen) (10(-7) M to 10(-5) M) inhibits BT-20 cell growth with maximum inhibition at 24-28h after plating. The inhibitory effect of OH-Tamoxifen is also demonstrated by a decrease in 3H-thymidine incorporation and by a reduction in cell number. These results suggest that OH-Tamoxifen is able to act upon an ER-cell line through a pathway which is different from that of estrogens.

1,25-Dihydroxyvitamin D3 inhibitory effect on the growth of two human breast cancer cell lines (MCF-7, BT-20).

1,25 (OH)2 D3 has been shown to be able to reduce the growth of several human cell lines. The effect of 1,25 (OH)2 D3 on the growth of breast cancer cell lines in relation to their oestrogen (ER) and progesterone (PGR) receptor content has been investigated. The growth inhibition of BT-20 and MCF-7 cell lines is related to the dose of 1,25 (OH)2 D3. It is dependent on the foetal calf serum concentration in the culture medium. At low concentration of 1,25 (OH)2 D3 the inhibitory effect is not detectable in the presence of 10% FCS. The rescue of cells from inhibition by serum was less effective when 1,25 (OH)2 D3 was present in the medium. The results of [3H]thymidine incorporation experiments and DNA measurements are in agreement with the reduction of cell number. Analysis in flow cytometry indicated a reduced number of cells in S phase. These data indicate that 1,25 (OH)2 D3 is able to modulate the growth of human breast adenocarcinoma cells regardless of their sex steroid dependency.

High affinity cytosol binding site(s) for antiestrogens in two human breast cancer cell lines and in biopsy specimens devoid of estrogen receptors.

It is known from previous investigations by other authors that the non-steroidal molecule Tamoxifen competes for estradiol binding sites in target tissues and displays partial agonist-antagonist effects. It is able to bind a cytosol protein distinct from ER which has been detected in target tissues, as well as in fetal target and non-target organs. The present work investigates the antiestrogen binding activity of human breast cancer cell lines and tumor biopsies. It is found that BT-20 and MDA-MB 231 cell lines devoid of ER and PGR contain a cytosol protein component able to bind antiestrogens with a high affinity (= 2 X 10(-9) M). The 3H-labeled complex prepared in hypotonic buffer sediments at 6.25 S in a sucrose gradient. A substantial amount of antiestrogen binding sites is found to be linked to the microsomal cell fraction, in agreement with previous data from other investigators. In experiments using whole cells incubated at 37 C, the complex is depleted from the cytosol compartment. A low amount of radioactivity is extracted from the purified nuclei. In the cytosol of human breast tumor biopsies the presence of antiestrogen binding sites is not exclusively associated with the presence of ER and PGR. The identity of the natural ligand which binds to these sites under physiological conditions merits investigation.

Comparison of protein phosphorylations in variant A431 cells with different growth responses to epidermal growth factor.

Growth of a selected variant of A431 cells (clone 29) is stimulated by epidermal growth factor (EGF) in contrast to the growth inhibition caused by EGF in an unselected clone, A431(8). Twelve phosphoproteins from each clone were compared to determine whether unique EGF-dependent substrate phosphorylations might explain the cells' differing growth responses to EGF. Treatment of both clone 29 and A431(8) cells with EGF increased phosphorylation of the EGF receptor/kinase and six cellular proteins identified on 2-dimensional polyacrylamide gels. Four of these proteins (the EGF receptor/kinase and proteins of 36, 70, and 81 kd) contained phosphotyrosine in both clone 29 and A431(8) cells, indicating that the same modification of several proteins occurred in cells which have totally different growth responses to EGF. Two proteins were identified whose phosphorylation was EGF dependent and which were unique to clone 29 cells; however, EGF increased phosphorylation of only serine residues in these proteins. This indicates that these proteins are not primary targets of the EGF-dependent tyrosine-specific protein kinase, but rather are substrates for serine-specific kinase(s) activated as a consequence of EGF:receptor interaction. cAMP, which inhibited growth of both clones, was utilized to compare the effects of EGF when the growth response of both cell lines was similar. In the presence of cAMP, EGF increased A431(8) cellular phosphotyrosine content and the phosphorylation of the same phosphotyrosine-containing proteins of both clone 29 and A431(8) cells. The in vivo activity of a second tyrosine-specific protein kinase, p60V -src in B77 Rous sarcoma virus (RSV)-transformed newborn rat kidney (NRK) cells, was also unaffected by cAMP. Thus cAMP did not block the in vivo activity of two tyrosine-specific kinases or the tyrosine phosphorylation of three specific protein substrates. A threshold model of tyrosine kinase activity is proposed as an alternative explanation for the differing growth responses to EGF.

Estradiol and progesterone receptor levels in human breast adenocarcinoma in relation to plasma estrogen and progesterone levels.

Plasma estrogen and progesterone levels were determined in 77 premenopausal and 137 menopausal women at the same time that estradiol receptor (ER) and progesterone receptor (PGR) assays were carried out on their breast cancers. The frequency of ER and PGR is approximately the same in premenopausal and postmenopausal women, but the ER content is much higher in postmenopausal women. Although this is usually ascribed to the occupancy of receptors by endogenous estrogen in premenopausal women, our observations suggest that this is unlikely. The higher ER content in postmenopausal women is probably due to the fact that the cyclic progesterone increase in premenopausal women limits estrogen stimulation of ER synthesis. Our data suggest that the circulating levels of estrogen in postmenopausal women are sufficient to stimulate ER and PGR when ER is functional. In premenopausal women, on the other hand, high levels of circulating progesterone may inhibit PGR, and the absence of PGR in the breast cancers of premenopausal women should be interpreted warily if the plasma level of progesterone is unknown.

[Proceedings: Cytosol estradiol receptors in 143 human female breast adenocarcinoma (author's transl)]. / Récepteurs d'oestradiol. Etude dans 143 adénocarcinomes mammaires chez la femme

PIP: Cytosol estradiol receptors were studied in 143 women aged 25-91 years with breast adenocarcinoma. Receptor assays were correlated with clinical response in 29 advanced cases. Hormonal treatment (ovariectomy, adrenalectomy, radiological hypophysectomy, medical hormone treatment) was effective in 20 of 22 cases in which receptors were found, but in only 1 of the 7 receptor-negative tumors. Estradiol receptor studies permit in vitro evaluation of hormone dependency of tumors.^ieng