Immunocytochemical technique for detection of prolactin (PRL) and growth hormone (GH) in hyperplastic and neoplastic lesions of dog prostate and mammary gland

An investigation on the relevance of prolactin, insulin-like growth factor-1 and 25-hydroxyvitamin D3 (25-OHD3 ) in canine benign prostatic hyperplasia in a predisposed breed model

Serum concentrations of prolactin (PRL), insulin-like growth factor-1 (IGF-1) and 25 hydroxyvitamin D₃ (25-OHD₃ ) were analysed to investigate their possible involvement in the pathogenesis of benign prostatic hyperplasia (BPH). For this, dogs of the Rhodesian Ridgeback (RR) breed were used because of a verified breed disposition for the development of BPH. Labrador Retrievers (LR) served as controls. The prostate gland status was characterised by the prostate gland volume, clinical signs of BPH (haemospermia and sonographic findings) and the plasma concentration of canine prostate-specific arginine esterase (CPSE). Breed specificity in the RR was expressed by a correlation of PRL with breed (p < 0.05). Similar relationships existed in the dogs with normal CPSE (CPSEn) with respect to the IGF-1 concentrations (LR: p < 0.05). The latter were negatively correlated with prostatic volume and age (both p < 0.05). Concentrations of 25-OHD₃ were tendentially (p = 0.18) lower in the RR with increased CPSE (CPSEi) compared with the CPSEn LR and RR showing clinical signs of BPH. A negative correlation between serum 25-OHD₃ and age (p < 0.05) existed in the CPSEi RR. Proof of 25-OHD₃ in prostatic secretion proved to be a breed specific feature in the RR (p < 0.0001). For all RR dogs showing clinical signs of BPH, a close to significant (p = 0.06) positive correlation with prostate gland volume was found. The results of the present study reveal no clear hints towards the significance of PRL and IGF-1 in the pathogenesis of canine BPH. In the RR breed there were indications of a causal relationship with age-dependent changes in the vitamin D metabolism. The data suggest the possibility of preventing or treating canine BPH by administering vitamin D or substances involved in the intraprostatic vitamin D metabolism.

Immunohistochemical Detection of Growth Hormone (GH) in Canine Hepatoid Gland Tumors

The aim of this study was to detect immunohistochemically means growth hormone (GH) in 24 hepatoid gland adenomas and 5 hepatoid gland carcinomas and to compare the difference of immunoreactivity between types of tumors. The tumors were classified according to the WHO standards. Tissue sections which were prepared from formalin-fixed, paraffin wax-embedded tissues from 25 male and 4 female dogs were carried out immunostaining using polyclonal primary anti-hGH and EnVision method. Of 24 hepatoid gland adenomas (perianal gland adenomas) 23 (95.8%) were positive. All 5 hepatoid gland carcinomas (perianal gland carcinomas) were positive. No statistically significant differences in percentage of labelled cells between malignant and benign tumors were seen. The present demonstration of GH in hepatoid gland tumors adds new data on GH in extra-pituitary tissues and hormon-dependent tumors.

Co-expression of GH and GHR isoforms in prostate cancer cell lines

Prostate cancer is a significant cause of morbidity and mortality in Western males. While it is known that androgens play a central role in prostate cancer development and progression, other hormones and growth factors are also involved in prostate growth. Insulin-like growth factor-I (IGF-I) plasma levels have been associated with prostate cancer risk, and growth hormone (GH), a major factor regulating IGF levels, also appears to have a role in prostate cancer cell growth. Most significantly, GH has been shown to increase the rate of cell proliferation in prostate cancer cell lines. We have now demonstrated the co-expression of GH and GH receptor (GHR) mRNA isoforms in the ALVA41, PC3, DU145, LNCaP prostate cancer cells by reverse transcription polymerase chain reaction. Sequence analysis has confirmed that these cell lines express the pituitary form of GH mRNA and also the placental mRNA isoform. These prostate cancer cell lines also express the full-length mRNA for the GHR and the exon 3 deleted isoform. We have also demonstrated the presence of GH and GHR proteins in these cell lines by immunohistochemistry. GH expression has not been described previously in human prostate cancer cells. The co-expression of GH and its receptor would enable an autocrine-paracrine pathway to exist in the prostate that would be capable of stimulating prostate growth, either directly via the GHR or indirectly via IGF production. The GH axis in the prostate could therefore be an important additional target for the future development of prostate cancer therapies.

Comparison of the histological changes in the dog after treatment with the progestins medroxyprogesterone acetate and proligestone

Administration of progestins in the dog may result in overproduction of growth hormone, suppression of the hypothalamic-pituitary-adrenocortical axis, and insulin resistance. In this paper we present a comparison of the histological findings in control dogs and dogs treated with either medroxyprogesterone acetate (MPA) or proligestone (PROL). Depot preparations of MPA or PROL were administered (SC) at 3-week intervals in two groups of seven ovariohysterectomized beagle dogs, after which three dogs of each group were killed. After a 6-month period without hormone treatment during which recovery was studied, the remaining dogs received five additional injections at the same interval and were subsequently killed. Tissue samples of four intact female beagle dogs served as controls. Progestin treatment resulted in atrophy of the adrenal cortex. In both MPA- and PROL-treated dogs, the thickness of the combined zona fasciculata and reticularis was significantly smaller than in control animals. In the mammary glands of progestin-treated dogs there were well developed alveoli and normal ducts adjacent to foci of hyperplastic ductular epithelium. Five dogs in each treatment group had developed benign mammary tumours which varied from simple tubular and papillary adenomas to benign complex and mixed tumours, whereas no mammary tumours were observed in the control animals. In each treatment group, steroid-induced hepatopathy was observed in the liver of three dogs. Vacuolation of the cells of the islets of Langerhans and the epithelium of the intercalated ducts was present in two dogs of each treatment group and was only observed after the second series of progestin administrations. Incidental findings included chronic pyelonephritis, aspecific dermatitis, and mucinous dysplasia of the gall bladder. No abnormalities were found in sections of spleen, lung, brain, or pituitary gland. There were no significant differences in the frequencies of the various abnormalities between MPA- and PROL-treated dogs. Our findings correspond with the clinical and biochemical results after treatment of dogs with MPA and PROL. The high incidence of mammary tumours might be associated with our recent finding that in the dog progestins induce ectopic production of growth hormone in the mammary gland. The dog might be a good model for further studies on hormonally induced breast cancers.

Growth hormone receptor expression in the Dunning R 3327 prostatic carcinoma of the rat

The Dunning R3327 rat carcinoma is an important model for human prostate adenocarcinoma. In the present study this tumor was further characterized by immunohistochemical demonstration of receptors for growth hormone (GH-R). Weak GH-R immunoreactivity was present in the secretory epithelial cells of the tumor acini. Large epithelial cells which were localized at the periphery of the acini and large cells in the stroma, which are probably derived from the epithelium ("Large neoplastic epithelial cells"), displayed a strong staining with one of the monoclonal antibodies (Mab 263) to GH-R. The presence of GH-R receptors in proliferating prostatic tumor cells supports the concept that GH reacts directly on prostate target tissue to facilitate tumor cell growth.

Immunoreactive prolactin in lesions and tumours of salivary glands

The prolactin binding in obstructive lesions and tumours of salivary glands was described by use of the immunohistochemical PAP technique. Normal salivary glands had prolactin binding cells in the striated ducts only. Chronic obstructive lesions of submandibular glands showed negative immunoreaction for prolactin binding in ductal cells, but positive staining of the luminal surface of ductal segments. In pleomorphic adenomas, occasional neoplastic cells located along the luminal borders of tubular, ductal, or of duct-like epithelial structures were strongly reactive with anti-prolactin and 26.5% of cases pleomorphic adenoma were positive for anti-prolactin. Adenoid cystic carcinoma exhibited positive prolactin binding on the luminal surface of some of tumour foci, but not in the rest of the tumour. Warthin's tumour was devoid of detectable prolactin binding.

Influences of dihydrotestosterone, testosterone, estradiol, progesterone, or prolactin on the cell kinetics of human hyperplastic prostatic tissue in organ culture

In an effort to characterize the hormone sensitivity of human benign prostatic hyperplasia (BPH) maintained in organ cultures for 12-72 h, the influence of 5-alpha-dihydrotestosterone (DHT), testosterone (T), 17-beta-estradiol (E2), progesterone (Pg), or prolactin (PRL) was assessed on the cell proliferation rate of 25 BPH specimens by the use of tritiated thymidine incorporation followed by autoradiography. Significant increases in the thymidine-labeling index (TLI: percentage of labeled nuclei) were observed in glandular tissue after a 36-h incubation period in presence of DHT, E2, Pg, or PRL in 52%, 44%, 28%, and 60% of BPH cases, respectively. Nonparametric statistics (Spearman and Kendall rank correlation tests) have shown that 1) the steroid-induced TLI increases are dependent on the basal rate of cell proliferation, while the PRL-induced effect is independent of it, and 2) all the steroid-mediated effects on BPH TLI are correlated together, whereas they seem to be independent of the PRL-induced TLI increase. When T was compared with DHT on nine BPH specimens, three were found to be sensitive to both hormones, and two responded to DHT only. We propose that our study methods are suitable as a means to assess the hormone sensitivity of individual cases of BPH and possibly prostatic tumors.

The influence of castration on the development of prostatic carcinoma in the dog. 43 cases (1978-1985)

Prostatic carcinoma (PC) was diagnosed in 43 dogs at the Michigan State University Veterinary Clinical Center (MSU-VCC) between 1978 and 1985. Of the 43 dogs with histologically confirmed PC, 19 (44.19%) had been castrated at least three years prior to the development of any prostatic disease. Seven of the castrates had been neutered at less than 12 months of age. Fourteen dogs (32.55%) were presented as intact males at the time of diagnosis. The remaining ten dogs (23.62%) had been castrated as treatment for presumptive prostatic disease prior to referral to the MSU-VCC. Dates of castration were known in all cases. In this study, therefore, castration at any age showed no sparing effect on the risk of development of PC in the dog. The etiology of PC in the dog may not be exclusively related to testicular hormones. Work in humans suggests that the adrenal and pituitary glands play a significant role in the disease. Preliminary work in dogs supports that nontesticular androgens exert a significant influence on the canine prostate.

An immunohistochemical study of the incidence and significance of human gonadotrophin and prolactin binding sites in normal and neoplastic human ovarian tissue

An immunoperoxidase technique has been utilised for the demonstration of follicle stimulating hormone (FSH), luteinising hormone (LH) and prolactin (PRL) binding sites in normal human ovaries and in a wide range of benign and malignant epithelial tumours of the ovary. The incidence of FSH, LH and PRL binding was, respectively, 32%, 41% and 39% in normal ovaries, 30%, 18.5% and 22.5% in benign epithelial tumours and 51%, 32% and 43% in malignant epithelial neoplasms. The incidence of FSH binding was significantly higher in malignant epithelial neoplasms than in either normal ovaries or benign epithelial tumours but otherwise no correlation was found between hormone binding capacity and the degree of malignancy of epithelial ovarian tumours, the histological type of the tumour, the degree of differentiation of the malignant epithelial tumours or the presence or absence of metastatic disease. Well differentiated malignant tumours did, however, tend to stain more strongly than did poorly differentiated neoplasms, thus suggesting that the number of binding sites per cell tends to decrease with decreasing degrees of differentiation.

The effect of prolactin on human BPH epithelial cell proliferation

Epithelial cell monolayers derived from specimens of human benign prostatic hyperplasia (BPH) tissue by an explant culture technique were cultured with prolactin in the presence and absence of androgens. Proliferation of the cells was measured by both autoradiographic assessment of [3H]-thymidine uptake and stathmokinetic procedures. Prolactin significantly stimulated the growth of these cells in the concentration range 0.5 mIU/ml to 10 mIU/ml but was inhibitory at a concentration of 100 mIU/ml. In the presence of testosterone (1 X 10(-7) M), prolactin at low concentrations (greater than 1 mIU/ml) but not at 10 mIU/ml, the concentration at which all other experiments were performed, produced a further stimulation in the proliferation. The increase in growth seen with cells cultured with 5 alpha-dihydrotestosterone (1 X 10(-7) M) was reduced with addition of prolactin at high concentrations (10-100 mIU). When the fetal calf serum used in the cultures was stripped of endogenous steroids, prolactin still increased cell proliferation, although to a reduced extent. This indicated that the effects of prolactin were not dependent on the presence of androgens.

Prolactin binding in normal human minor salivary gland tissue: an immunohistochemical study

The breast and salivary gland exhibit some similarities in the biochemical and cellular spheres. There are also some tumors that are common to both organs. The protein hormone prolactin seems to play a role in the health and disease of the mammary gland, and an investigation was launched to see if this hormone exhibited any binding activity in normal human minor salivary gland. With the use of immunohistochemical methods, dose-dependent staining for prolactin binding was demonstrated in the striated and collecting ducts in four of six specimens of normal human minor salivary gland (two males and two females). The hormone concentrations used ranged from 6.25 ng/ml to 500 ng/ml of highly purified rat prolactin. A review of known functions of prolactin in man and other animals is presented, and it was concluded that normal human minor salivary gland tissue possesses binding sites for prolactin, which suggests that prolactin may play a role in the metabolic functioning of the salivary duct cells.

Nonsteroidal serum factors involved in the regulation of the proliferation of canine prostatic epithelial cells in culture

Canine prostatic epithelial cells were cultured in primary monolayers in order to define those factors that induce a proliferative response at the cellular level. Cultures were performed in a serum-free medium or in a medium supplemented either with fetal bovine serum or dog serum in the presence or absence of several sex steroids (androstenedione, testosterone, dihydrotestosterone, 3 alpha- and 3 beta-androstanediols, epitestosterone, epidihydrotestosterone, estrone, estradiol, and progesterone). Cell proliferation was observed in the absence of serum and exogenous steroids. The rate of cell division was serum dependent and steroid independent. Pretreatment of sera with charcoal had no effect on their mitogenic activities. Cells maintained in an endocrine milieu prior to tissue dispersion and throughout the whole procedure proliferate to the same extent as those deprived of hormones, whether free of serum or added supplements. The addition of insulin (2 micrograms/ml), dog prolactin (up to 25 ng/ml) and zinc (10(-8) to 10(-2) M) in a serum-free medium did not induce cell responsiveness to steroids. Dihydrotestosterone, 3 alpha-androstanediol, and estradiol alone or in combinations known to induce the growth of the canine prostate in vivo were ineffective in vitro. The proliferative responses to sera were time and concentration dependent, and dog serum was more potent than fetal bovine serum. Thus, humoral factors other than steroids, prolactin, insulin, or zinc may be of importance in the activation of epithelial cells involved in the development of prostatic hyperplasia and adenocarcinoma.

The localization of prolactin binding sites in human breast tissue

An immunohistochemical method involving the application of purified human prolactin and a specific antiserum to human prolactin, followed by the peroxidase-anti-peroxidase immunoperoxidase technique, has been used to detect prolactin binding in benign and malignant human breast tissue. The use of fresh, frozen material has been found to be essential. Prolactin binding has been shown to be a consistent feature of benign breast tissue but a variation within samples has been noted which is irrespective of hyperplastic changes. Fifty six percent of breast carcinomas gave a positive reaction but heterogeneity of binding has been shown to be a significant feature. A relationship between the presence and extent of prolactin binding and good histological differentiation of the tumours has been noted. It is concluded that immunohistochemistry is a suitable method for the demonstration of prolactin binding sites in human breast tissue and can provide useful information with regard to tumour heterogeneity.

Use of monoclonal antihapten antibodies for immunolocalisation of tissue antigens

The applicability of a hapten-antihapten sandwich technique incorporating a monoclonal antihapten bridge antibody to localisation of tissue antigen is described. The results show that the method is both versatile and selective and has the potential of being even more sensitive than currently used immunoperoxidase methods.

Human and rat growth hormones enhance guanylate cyclase activity

The objective of this investigation was to determine whether physiological levels of growth hormone have part of their mechanism of action through stimulation of guanylate cyclase (EC 4.6.1.2.). Rat and human growth hormones enhanced the activity of soluble guanylate cyclase two- to fourfold in rat gracilis anticus skeletal muscle, liver, lung, heart, pancreas, and kidney cortex at a concentration of 10 nM. Dose-response relationships revealed that more than half-maximal stimulation of guanylate cyclase activity was seen at a concentration as low as 10 nM and nonstimulation of guanylate cyclase activity was seen when the concentration was decreased to 1 nM. Maximal enhancement was seen at 100 nM of growth hormone, and there was no further enhancement when the concentration was increased to the micromolar or millimolar range. Thus, the data in this investigation indicate that at concentrations at which growth hormone is known to cause its growth-promoting effects, growth hormone does cause an enhancement of the activity of the guanylate cyclase-cyclic GMP system.

The immunocytochemical detection of protein hormones in human prostatic tissues

The immunocytochemical detection of four pituitary protein hormones in tissue from 13 patients with benign prostatic hyperplasia has been described. There have been marked differences in the distribution and intensity of reaction product attributable to the various hormonal antisera. The intracellular presence of endogenous prolactin and FSH in the epithelial cytoplasm has been suggested together with the stromal localization of growth hormone and prolactin. Minimal diffuse staining over most cellular components was observed with the LH antiserum. This technique has provided an invaluable means of studying the potential involvement of pituitary protein hormones in the control of prostatic function and disease.