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We have studied the clarifying activity of a purified peptide fraction of gametic origin in senile cataract of the dog. The active substance, administered intramuscularly, had significant and durable clarifying effects on the cortical area of the lens. [ABSTRACT FROM PUBLISHER]

Three peptides were isolated from bovine seminal plasma and purified to homogeneity. The amino acid sequences, as determined by FAB mass spectrometry, are the following: pGlu-Ala-Glu-Ser-Asn-OH, pGlu-Ala-Glu-Ser(PO3H2-Asn-OH and pGlu-Val-Gly-Glu-Ser-Glu-Asn-OH. These three peptides and some of their analogues were synthesized using liquid- and solid-phase techniques. The pentapeptide pGlu-Ala-Glu- Ser-Asn-OH showed a remarkable affinity for kinase NII and a strong inhibiting activity in DNA transcription. These findings support the hypothesis that phosphorylated acidic domains of nuclear non-histone proteins could bind to DNA, thereby controlling transcription.

Partial hepatectomy (PH) (70% resection) causes within 4 hr an accumulation of ornithine decarboxylase (EC 4.1.1.17, ODC) mRNAs concomitant with an increase in ODC activity, maximum values being observed at 8 and 16 hr, respectively. In the early hours of hepatic regeneration, enhancement of transcriptional-rate of ODC gene, demonstrated by nuclear run-on analysis, can account for the accumulation of ODC mRNAs. The involvement of catecholamines in these processes is demonstrated by using prazosin and propranolol, specific antagonists of alpha 1 and beta adrenoceptors, respectively. Prazosin reduces almost completely the rise of ODC activity at 4 hr, without affecting mRNA levels. At 16 hr, enzyme activity and mRNAs increase, however, over the values observed in regenerating liver of prazosin-untreated animals. These findings suggest that alpha 1-receptor activation triggers positive control signals for ODC gene expression at the early time of liver regeneration and, on the contrary, negative signals at later times by mainly post-transcriptional and transcriptional mechanisms, respectively. Propranolol reduces similarly the initial 4 hr-rise of ODC activity. These results indicate that activation of both alpha 1- and beta-adrenoceptors causes the large increase in ODC activity. Pharmacological manipulation of intracellular Ca2+ levels by verapamil, a Ca2(+)-channel blocker, or neomycin, an inhibitor of Ca2+ release from endogenous stores, diminishes ODC activity at 4 and 16 hr after PH. ODC mRNA levels, which are not modified at 4 hr, increase over the values of partially hepatectomized rat liver at 16 hr. Trifluoperazine inhibits both ODC activity and mRNA accumulation at the times studied. As a working hypothesis it is proposed that Ca2(+)-mediated processes induced by catecholamines are involved in ODC gene expression during the prereplicative phase of liver regeneration.

A highly reliable technique for the determination of progesterone in milk has been developed, and its application to pregnancy diagnosis in cows is reported. The method is characterized by an activated charcoal treatment of the samples, extraction of the absorbed progesterone by an organic solvent, followed by RIA. The application of the method to pregnancy diagnosis, 21--23 days after artificial insemination, shows that 5 ng/ml is the most useful value to discriminate between pregnant and non-pregnant animals, with greatest precision on the 21st day, in that 93.5% of pregnant and 100% of non-pregnant animals were correctly diagnosed.

The s.c. administration for 25 days of the inhibin-like factor extracted from bull spermatozoa to immature 20-day-old male rats reduced serum FSH levels by about 60% and serum LH and testosterone levels by about 50%. However, neither tubular nor interstitial modifications of the histological appearance of the testis were found and there were no changes in the activity of delta 5-3 beta-hydroxysteroid dehydrogenase. The assay described could be usefully employed for evaluating the activities of inhibin-like factors.

An oligopeptide fraction purified from the extracellular compartment of bull semen and strongly interacting with DNA was shown to hinder mononucleotide polymerizations to DNA and RNA in vitro. The fraction, collectively called seminal plasma inhibitor, was active in the endogenous DNA and RNA polymerase reactions of the nuclei from rat hepatocytes and in the analogous nucleotide polymerizations catalyzed by purified enzymes of bacterial origin. The type of the induced inhibition was studied using the RNA polymerase from Escherichia coli as a representative nucleotidyl transferase. In the enzymatic polycondensation of mononucleotides, the seminal plasma inhibitor appeared to exert its effect mainly by a competitive inhibition for the utilization of DNA templates without specificity with respect to the source and the base sequence of DNA. Concavities of the plots of V0/Vi versus the amounts of inhibitor in the nucleotide polymerizing reactions and of the Dixon plots in the assays of RNA polymerase from E. coli suggested that the isolated oligopeptide fraction contained more than one active molecular species with differential effects at low and high doses. Preliminary results on the microheterogeneity of the seminal plasma inhibitor supported this contention.

The gastric antisecretory activity of an inhibitor newly isolated from human urine (Human Urinary Gastric Inhibitor or HUGI) has been studied. HUGI was given intravenously and its activity determined in the following test systems: gastric secretion in the rat with pyloric ligation; gastric secretion in the dog with a Heidenhain pouch stimulated with pentagastrin, histamine and a protein meal; acid secretion by the isolated gastric mucosa of the rat; gastrointestinal motility; bile flow and gall-bladder tone and arterial and venous blood pressure and heart rate. HUGI was found to have marked activity only in the pyloric-ligated rats and in the dogs with Heidenhain pouches stimulated by a protein meal. Particularly in the dog, HUGI (0.1 to 6.4 micrograms/kg, i.v) markedly inhibited gastric secretion, dose-dependently and without changing the plasma gastrin concentration. Negative results were obtained in the other tests, but these results serve to demonstrate that HUGI is an inhibitor well-differentiated from other glycoproteins or peptides with gastric antisecretory activity, such as urogastrone and GIP. The results obtained to date are not sufficient to allow the mechanism of action of HUGI to be defined.

The effect of a water soluble nonsteroidal factor extracted from the male gamete on the activity of certain liver inducible enzymes during aging has been examined. Three enzymes have been studied: delta-aminolevulinic acid synthetase, NADPH-oxidase and tyrosine aminotransferase whose inducibility by ethanol, phenobarbital and ACTH, respectively, show age dependent alterations. The results here reported show that this factor is able to restore the enzyme inducibility in the liver of aging (600-day-old) rats without affecting the response of young (40-day-old) rats. Since the enzyme inducibility is altered during aging, and in the majority of rat hepatomas this factor might enter, possibly, in the regulation of enzyme activity also of neoplastic cells.

A peptide fraction, called seminal plasma inhibitor (SPI), present in mammalian semen, was shown to block DNA transcription in vitro (Lugaro et al., 1984). Peptides responsible for this effect were partially purified from bovine seminal plasma. This report outlines the preparative procedure for the isolation of SPI and provides preliminary information on the action mechanism of the RNA synthesis inhibition.

The effect of an acidic factor of low molecular weight (about 1,000 daltons), extracted from bovine spermatozoan DNA, on the inducibility of delta-aminolevulinic acid synthase by ethanol during aging in rat has been examined. The increased enzyme inducibility in 600-day old rats is supported by stimulation of transcriptional and translational processes; on the contrary, in 30-day old rats, the higher enzyme values induced by ethanol are significantly decreased after factor treatment. The active factor is strongly DNA-bound in the native spermatozoan DNA. This would imply a possible role in regulating gene expression in vivo.