The vehicle for zinc in the prostatic secretion of dogs

Molecular Biomarkers of Canine Reproductive Functions

The aim of the current study is to review potential molecular biomarker substances selected so far as useful for assessing the quality of dog semen. Proteins, lipids, carbohydrates, and ions can serve as molecular biomarkers of reproductive functions (BRFs) for evaluating male reproductive health and identifying potential risk factors for infertility or reproductive disorders. Evaluation of BRF levels in semen samples or reproductive tissues may provide insights into the underlying causes of infertility, such as impaired sperm function, abnormal sperm-egg interaction, or dysfunction of the male reproductive tract. Molecular biomarker proteins may be divided into two groups: proteins that are well-studied, such as A-kinase anchoring proteins (AKAPs), albumins (ALBs), alkaline phosphatase (ALPL), clusterin (CLU), canine prostate-specific esterase (CPSE), cysteine-rich secretory protein 2 (CRISP2), lactotransferrin (LTF), metalloproteinases (MMPs), and osteopontin (OPN) and proteins that are not well-studied. Non-protein markers include lipid-based substances (fatty acids, phosphatidylcholine), carbohydrates (glycosaminoglycans), and ions (zinc, calcium). Assessing the levels of BRFs in semen samples may provide valuable information for breeding management and reproductive assessments in dogs. This review systematizes current knowledge that could serve as a starting point for developing practical tests with the use of biomarkers of canine reproductive functions and their predictive value for assisted reproductive technique outcomes and semen preservation.

Zinc: A Necessary Ion for Mammalian Sperm Fertilization Competency

The importance of zinc for male fertility only emerged recently, being propelled in part by consumer interest in nutritional supplements containing ionic trace minerals. Here, we review the properties, biological roles and cellular mechanisms that are relevant to zinc function in the male reproductive system, survey available peer-reviewed data on nutritional zinc supplementation for fertility improvement in livestock animals and infertility therapy in men, and discuss the recently discovered signaling pathways involving zinc in sperm maturation and fertilization. Emphasis is on the zinc-interacting sperm proteome and its involvement in the regulation of sperm structure and function, from spermatogenesis and epididymal sperm maturation to sperm interactions with the female reproductive tract, capacitation, fertilization, and embryo development. Merits of dietary zinc supplementation and zinc inclusion into semen processing media are considered with livestock artificial insemination (AI) and human assisted reproductive therapy (ART) in mind. Collectively, the currently available data underline the importance of zinc ions for male fertility, which could be harnessed to improve human reproductive health and reproductive efficiency in agriculturally important livestock species. Further research will advance the field of sperm and fertilization biology, provide new research tools, and ultimately optimize semen processing procedures for human infertility therapy and livestock AI.

Zinc content in the epididymis, vas deferens, prostate, and seminal vesicles of juvenile rhesus monkey (Macaca mulatta): effect of androgen and estrogen

The zinc content in the three segments of the epididymis (caput, corpus, and cauda), vas deferens, seminal vesicles, and prostate of juvenile monkeys was determined by atomic absorption spectrophotometry. Zinc content (micrograms/gm wet weight) was found to be maximum (328) in the vas deferens; in the other organs it measured in the following order: caput 191, corpus 238, cauda 193, prostate 133 and seminal vesicles 85. In order to investigate the endocrine control of the zinc in these organs, two groups of animals were treated with testosterone propionate (2 mg) or estradiol dipropionate (10 micrograms) once daily for 30 days. In response to androgen, a rise in both concentration and content of zinc was evident only in the prostate. The results further suggested that the prostatic zinc may be under dual hormonal control, but in the epididymis and vas deferens it may be under the influence of estrogen. It is concluded that the hormonal effects on zinc content and growth stimulation in accessory sex organs are quite separate and may be under different hormonal control.

Evidence against a zinc binding peptide in pilocarpine-stimulated canine prostatic secretions

Pilocarpine-stimulated canine prostatic secretions were subjected to gel filtration chromatography over Sephadex G-100 and Bio Gel P-4. Free zinc and the zinc in pilocarpine-stimulated canine prostatic secretions were observed to elute in the same fractions from the Sephadex G-100 column. In addition, Sephadex G-100 chromatography could not resolve free zinc from the small peptide bacitracin. However, a column packed with Bio Gel P-4 could resolve free zinc and bacitracin. When pilocarpine-stimulated canine prostatic secretions were chromatographed over the Bio Gel P-4 column, the major portion of the zinc eluted in the same fractions as did free zinc. No zinc was observed in the fractions where the small peptide bacitracin was found to elute. These results indicate that contrary to a previous report, zinc in pilocarpine-stimulated canine prostatic secretions was not bound to an eight amino acid peptide, but, rather, behaved chromatographically like free zinc.

Cadmium-induced prostate metallothionein in the rabbit

Male rabbits injected with cadmium chloride (4 mg/kg) lead to the detection of a major metal-containing peak in the prostate cytosol. Chromatographic profiles indicate the presence of metallothionein (MT). MT is associated with zinc ion. The rabbit prostate, like that of other species, contains zinc-associated proteins, and this protein possesses many of the characteristics of metallothionein.

Passage of chemicals into human and animal semen: mechanisms and significance

This review will begin with a brief account of the secretory mechanisms operating in the male reproductive tract. The entry of the different chemicals will be dealt with; with separate reference to testicular fluids, epididymal plasma, prostatic and vesicular secretions, and whole semen. Examples will be given of a number of chemical substances capable of passing into the secretions of the male reproductive tract and semen, in man and in animals--antispermatogenic and antiandrogenic agents, industrial chemicals, chemotherapeutic drugs, food additives, etc. The review will end with a critical appraisal of the methods involved and the results obtained from analyses of various chemicals in semen.

Selective binding of zinc ions to heparin rather than to other glycosaminoglycans

The relative binding affinity of Zn2+ to several glycosaminoglycans was determined by gel-filtration chromatography. Binding was observed only between Zn2+ and heparin. No binding was observed between Zn2+ and chondroitin 4-sulphate, chondroitin 6-sulphate, dermatan sulphate of hyaluronic acid. All of the glycosaminoglycans contained carboxy groups, but only heparin bound Zn2+. This observation suggests that, contrary to a previously proposed hypothesis, simple electrostatic interactions between the negatively charged carboxy groups of the glycosaminoglycans and the positively charged Zn2+ cannot explain the observed binding.

Prostatic antibacterial factor. Identity and significance

Normal human prostatic fluid possesses pronounced antibacterial activity. This activity is absent or markedly diminished in the fluid of men with chronic bacterial prostatitis. Ion-probe and mass spectrographic analysis of this antibacterial factor has shown it to be a zinc salt. Prostatic fluid zinc levels in 15 men with chronic bacterial prostatitis averaged 50 mug. per milliliter (range 0 to 139 mug. per milliliter). The zinc level in the expressed prostate secretion (EPS) of 49 control men averaged 448 mug. per milliliter (range 150 to 1,000 mug. per milliliter). There was no overlap in the range of zinc values between the two groups. The decrease in EPS zinc concentration in the patient population was not secondary to a decreased serum zinc level. Exogenous zinc given orally did not increase the EPS zinc level. The decrease in EPS zinc was not limited to infected prostatic fluid cultures and may precede the entry of bacteria into the prostate. The data presented suggest that zinc may serve as an in vivo defense mechanism against prostatic invasion and subsequent urinary tract infections in men.