Seasonal changes in urinary prostate-specific antigenic activity in male Japanese macaques (Macaca fuscaa fuscata)

Molecular histology of spermatogenesis in the Japanese macaque monkey (Macaca fuscata)

Non-human primates are our closest relatives and therefore offer valuable comparative models for human evolutionary studies and biomedical research. As such, Japanese macaques (Macaca fuscata) have contributed to the advancement of primatology in both field and laboratory settings. Specifically, Japanese macaques serve as an excellent model for investigating postnatal development and seasonal breeding in primates because of their relatively prolonged juvenile period and distinct seasonal breeding activity in adulthood. Pioneering histological studies have examined the developmental associations between their reproductive states and spermatogenesis by morphological observation. However, a molecular histological atlas of Japanese macaque spermatogenesis is only in its infancy, limiting our understanding of spermatogenesis ontogeny related to their reproductive changes. Here, we performed immunofluorescence analyses of spermatogenesis in Japanese macaque testes to determine the expression of a subset of marker proteins. The present molecular histological analyses readily specified major spermatogonial subtypes as SALL4⁺ A spermatogonia and Ki67⁺/C-KIT⁺ B spermatogonia. The expression of DAZL, SCP1, γH2AX, VASA, and calmegin further showed sequential changes regarding the protein expression profile and chromosomal structures during spermatogenesis in a differentiation stage-specific manner. Accordingly, comparative analyses between subadults and adults identified spermatogenic deficits in differentiation and synchronization in subadult testes. Our findings provide a new diagnostic platform for dissecting spermatogenic status and reproduction in the Japanese macaques.

Objective non-intrusive markers of sperm production and sexual activity

Objective studies of men's reproductive function are hindered by their reliance on: (i) self-reporting to quantify sexual activity and (ii) masturbation to quantify sperm output rendering both types of estimate vulnerable to unverifiable subjective factors. We therefore examined whether detection of spermatozoa and measurement of prostate-specific antigen (PSA) in urine could provide objective semiquantitative estimates of sperm output and recent ejaculation, respectively, using widely available laboratory techniques. Of 11 healthy volunteers who provided urine samples before and at intervals for 5 days after ejaculation, sperm was present in 2/11 men before, and in all 11/11 samples immediately after ejaculation, but by the second and subsequent void, spermatozoa were present in ∼10%. PSA was detectable at high levels in all urine samples, peaking at the first post-ejaculatory sample but returning to baseline levels by the second post-ejaculatory void. We conclude that urinary spermatozoa and PSA are objective biomarkers for sperm production and sexual activity, but only for a short-time window until the first post-ejaculatory urine void. Hence, for a single urine specimen, the presence of spermatozoa and PSA are valid biomarkers, reflecting sperm production and recent ejaculation only until the next micturition, so their measurement should be restricted to the first morning urine void.

Kallikreins on steroids: structure, function, and hormonal regulation of prostate-specific antigen and the extended kallikrein locus

The 15 members of the kallikrein-related serine peptidase (KLK) family have diverse tissue-specific expression profiles and putative proteolytic functions. The kallikrein family is also emerging as a rich source of disease biomarkers with KLK3, commonly known as prostate-specific antigen, being the current serum biomarker for prostate cancer. The kallikrein locus is also notable because it is extraordinarily responsive to steroids and other hormones. Indeed, at least 14 functional hormone response elements have been identified in the kallikrein locus. A more comprehensive understanding of the transcriptional regulation of kallikreins may help the field make more informed hypotheses about the physiological functions of kallikreins and their effectiveness as biomarkers. In this review, we describe the organization of the kallikrein locus and the structure of kallikrein genes and proteins. We also focus on the transcriptional regulation of kallikreins by androgens, progestins, glucocorticoids, mineralocorticoids, estrogens, and other hormones in animal models and human prostate, breast, and reproductive tract tissues. The interaction of the androgen receptor with androgen response elements in the promoter and enhancer of KLK2 and KLK3 is also summarized in detail. There is evidence that all kallikreins are regulated by multiple nuclear receptors. Yet, apart from KLK2 and KLK3, it is not clear whether all kallikreins are direct transcriptional targets. Therefore, we argue that gaining more detailed information about the mechanisms that regulate kallikrein expression should be a priority of future studies and that the kallikrein locus will continue to be an important model in the era of genome-wide analyses.

The seminal coagulum favours passage of fast-moving sperm into the uterus in the black-handed spider monkey

In addition to gametes, mammalian internal fertilisation has required the evolution of assorted anatomical, physiological and biochemical devices to deal with intra- and inter-sexual conflict such as sperm competition and female cryptic choice respectively. The seminal coagulum of primates and other mammals is viewed as one of such devices. Among primates, the seminal coagulum characteristically occurs in multi-male and multi-female species, leading us to suppose that it intervenes in sperm competition. However, it can also provide cues to the female reproductive tract about male desired or undesired traits, and therefore deter or favour sperm survival and migration. The present work investigates whether the seminal coagulum of the black-handed spider monkey enhances sperm fertilisation chances by improving the female reproductive tract conditions, and if the female reproductive tract is ‘blind’ to semen or behaves selectively towards ejaculates of different males. A series of artificial inseminations were done in five females, using the ejaculates of three different males, one at a time, and measuring the presence of distinct types of sperm inside the uteri at 10, 30 and 60 min following the insemination. The presence of coagulum, menstrual phase, and male and female identity only affected fast, straight-moving sperm, with larger amounts of fast sperm appearing inside the uteri when ejaculates had seminal coagulum, as well as when in the periovulatory phase. There was great intra-uterine fast-sperm variation regarding which male's semen inseminated which female. The results provide evidence to account for sexual conflict in the spider monkey as well as a methodological approach to this kind of study.