Effects of taurine on the motility and intracellular free Ca2+ concentration of fowl spermatozoa in vitro.

The effects of taurine on the motility and intracellular free Ca2+ concentration of fowl spermatozoa were investigated in vitro. The addition of taurine, within the range of 0-5 mmol l(-1), did not appreciably affect the motility of intact fowl spermatozoa. Motility remained almost negligible at 40 degrees C, while vigorous movement was observed at 25 degrees C. Even with the addition of Ca2+ before the addition of taurine, neither stimulation nor inhibition of motility was observed compared with the control (no addition of taurine). Similar results were obtained by the addition of taurine and calyculin A, a specific inhibitor of protein phosphatases. There were no changes in intracellular free Ca2+ concentrations, measured by a fluorescent Ca2+ indicator, fura-2, in taurine-treated spermatozoa. These results suggest that taurine is not involved in the regulation of fowl sperm motility and metabolism by intracellular Ca2+ mobilization in vitro.

Amino acid secretion of the hen's oviduct during the egg formation cycle.

The free amino acid content of 34 hens' oviducts was determined in different phases of the egg formation cycle. In addition, quantitative changes of transmitter-type amino acids (glutamic acid, aspartic acid, taurine, glycine) were monitored in comparison with those of other amino acids participating in protein synthesis (e.g., lysine, tyrosine, valine). Different portions of the hen's oviduct, primarily the magnum and the uterus, were characterised by substantial amino acid secreting activity. The amino acids detectable in the highest quantity were taurine, glutamic acid, glycine and aspartic acid. These amino acids were present in high concentrations throughout the egg formation cycle, but their quantity abruptly decreased at the time of oviposition and ovulation. The quantitative changes of transmitter-type amino acids are mostly independent of those of other amino acids participating in protein synthesis. Since in our earlier in vitro studies the concentration changes of the transmitter amino acids studied were found to affect the motility and agglutination of spermatozoa, they--besides other factors--can be assumed to exert an influence on the sperm storage and release processes of the uterovaginal sperm storage tubules located in the oviduct of birds.

Motility and agglutination of fowl spermatozoa in media of different amino acid content and pH value in vitro.

The objective of the present experiments was to study some properties of fowl spermatozoa which may play a role in the sperm storage and emptying mechanism of the uterovaginal sperm storage tubules (SST) of the hen. The effects exerted by different amino acids (aspartic acid, Asp; glutamic acid, Glu; gamma-aminobutyric acid, GABA; glycine, Gly) and by the pH of the environment at 24 and 39 degrees C on the motility and agglutination of cock spermatozoa were studied in vitro. The spermatozoa did not show agglutination in the presence of Asp and Glu, and became immobilised if the concentration of Glu or the acidity of the environment was increased. In neutral solutions of GABA and Gly or in a faintly alkaline solution characteristic plait-like conglomerations could be seen. The motility of spermatozoa immobilised by Glu could be restored in a varying degree by the addition of GABA or Gly. At a temperature of 24 degrees C, the spermatozoa became immobilised in a medium of pH 6.0 while showed maximum motility at pH 7.1. At 39 degrees C, the spermatozoa were immobilised at higher pH (6.2) and required a pH value as high as 7.4-7.5 to show the highest motility. Spermatozoa inactivated in an acidic solution could be immediately mobilised by alkalisation of the medium, irrespective of the Ca2+ content of the solution. Thus, Ca2+ was not found to play a role in the reactivation of spermatozoa. Nevertheless, marked differences were observed in the maintenance of sperm motility between solutions either containing or lacking Ca2+. As the concentration changes of the above-mentioned amino acids and the pH changes were found to affect the motility and agglutination of spermatozoa in vitro, they may influence also the regulatory mechanism of the uterovaginal SST during the egg-formation cycle in vivo.

Studies on canine mammary tumours. I. Age, seasonal and breed distribution.

The incidence as well as age, seasonal and breed distribution of canine mammary tumours (n = 521) were studied at the Clinic of Obstetrics and Gynaecology of the University of Veterinary Science, Budapest, between 1985 and 1989. In 39 cases of mammary tumour, blood plasma oestradiol (E2) and progesterone (P) concentrations were also determined. Of all dogs referred to the clinics of the University in 1985, 0.7% had mammary tumour. On the average, 104 +/- 9.3 cases of mammary tumour were recorded at the Clinic of Obstetrics per year. This number did not increase after the Chernobyl atomic reactor catastrophe of 1986. The age distribution of canine mammary tumour found in this study shows good agreement with earlier data of the literature: mammary tumour showed the highest incidence in 10 years old dogs. The incidence of mammary tumour kept increasing with age until the 14th year of life (as expressed in per cent of animals of identical age). The number of mammary tumours was markedly higher in the spring (April-May) and autumn (September). This seasonality was demonstrable in 11 to 16 years old bitches, too. On the basis of the blood plasma E2 and P profiles, 61.5% of the clinically anoestrous animals were found to be cycling. The strikingly high ratio of pulis among dogs with mammary cancer was suggestive of a breed disposition.

Studies on canine mammary tumours. II. Oestradiol and progesterone receptor binding capacity and histological type.

Tissue samples taken from the mammary gland of 42 dogs (age: 6 to 12 years) were examined. Thirty-eight samples showed neoplasia: 36 were epithelial while the remaining 2 proved to be connective tissue tumours. Thirty-four % of the neoplasms were new benign tumours (most frequently adenoma and fibroadenoma) and 66% were malignant ones (mainly adenocarcinoma). The oestrogen receptor (ER) and progesterone receptor (PR) binding capacity was determined on 21 tissue samples using the method of EORTC (1980). The connective tissue tumours and non-tumourous tissues contained no sexual steroid receptor. 71.4% of all tissue samples contained receptors. 61.9% of the samples was ER+, 42.8% was PR+, 33.3% contained both receptors, 28.6% was only ER+ and 9.5% only PR+. The average ER and PR binding capacity was 120.3 (5.0-622.8) and 266.7 (92.3-475.0) fmol/mg cytosol protein, respectively. No difference in receptor positivity was demonstrable between the benign and the malignant tumours. PR negativity accompanied by ER positivity was more common in the case of benign tumours. ER binding capacity tended to be correlated with age: this correlation could be described with a hyperboloid regression curve (r = -0.5931; 0.06 > p > 0.05).