Effect of long-term treatment with aromatase inhibitor on testicular function of adult male bonnet monkeys (M. radiata)

The role/need for estrogen in regulating testicular function of adult male bonnet monkeys (M. radiata) has been investigated by dosing orally a group of five normal males 2.5 mgs of CGP 47645, a long-acting nonsteroidal aromatase inhibitor (AI), once every 5 days for over 150 days. Such treatment resulted in a 10-fold increment in nocturnal serum testosterone (T) levels, which were sustained for 85 days of treatment, and a twofold increment in basal serum T levels was present throughout the 150 days of treatment. Analysis of ejaculated semen showed a marked reduction (~90%) in sperm counts in four out of five monkeys between Days 55-85 of treatment. During this period, the motility score also was markedly reduced from a normal score of 3-5 to 0-2. Flow cytometric analysis of testicular germ cells obtained from biopsy tissue taken on Days 63 and 120 indicated a marked reduction only in elongating/elongated spermatid population (compared to Day 0 values), suggesting inhibition in spermiogenic process. Epididymal sperm maturation also seemed effected as sperm chromatin, on flow cytometric analysis for decondensability following exposure to 5 mM dithiotreitol, showed to be in a hypercondensed state. This study thus indicates that estrogen has an important role in providing normal testicular and sperm function in the primate

Differentiation of primate primordial germ cell-like cells following transplantation into the adult gonadal niche.

A major challenge in stem cell differentiation is the availability of bioassays to prove cell types generated in vitro are equivalent to cells in vivo. In the mouse, differentiation of primordial germ cell-like cells (PGCLCs) from pluripotent cells was validated by transplantation, leading to the generation of spermatogenesis and to the birth of offspring. Here we report the use of xenotransplantation (monkey to mouse) and homologous transplantation (monkey to monkey) to validate our in vitro protocol for differentiating male rhesus (r) macaque PGCLCs (rPGCLCs) from induced pluripotent stem cells (riPSCs). Specifically, transplantation of aggregates containing rPGCLCs into mouse and nonhuman primate testicles overcomes a major bottleneck in rPGCLC differentiation. These findings suggest that immature rPGCLCs once transplanted into an adult gonadal niche commit to differentiate towards late rPGCs that initiate epigenetic reprogramming but do not complete the conversion into ENO2-positive spermatogonia

Fetal cyclophosphamide exposure induces testicular cancer and reduced spermatogenesis and ovarian follicle numbers in mice

<div><p>Exposure to radiation during fetal development induces testicular germ cell tumors (TGCT) and reduces spermatogenesis in mice. However, whether DNA damaging chemotherapeutic agents elicit these effects in mice remains unclear. Among such agents, cyclophosphamide (CP) is currently used to treat breast cancer in pregnant women, and the effects of fetal exposure to this drug manifested in the offspring must be better understood to offer such patients suitable counseling. The present study was designed to determine whether fetal exposure to CP induces testicular cancer and/or gonadal toxicity in 129 and in 129.MOLF congenic (L1) mice. Exposure to CP on embryonic days 10.5 and 11.5 dramatically increased TGCT incidence to 28% in offspring of 129 mice (control value, 2%) and to 80% in the male offspring of L1 (control value 33%). These increases are similar to those observed in both lines of mice by radiation. <i>In utero</i> exposure to CP also significantly reduced testis weights at 4 weeks of age to ∼70% of control and induced atrophic seminiferous tubules in ∼30% of the testes. When the <i>in utero</i> CP-exposed 129 mice reached adulthood, there were significant reductions in testicular and epididymal sperm counts to 62% and 70%, respectively, of controls. In female offspring, CP caused the loss of 77% of primordial follicles and increased follicle growth activation. The results indicate that i) DNA damage is a common mechanism leading to induction of testicular cancer, ii) increased induction of testis cancer by external agents is proportional to the spontaneous incidence due to inherent genetic susceptibility, and iii) children exposed to radiation or DNA damaging chemotherapeutic agents <i>in utero</i> may have increased risks of developing testis cancer and having reduced spermatogenic potential or diminished reproductive lifespan.</p></div

Mating behaviour of the Indian grey mongoose Herpestes edwardsii edwardsii Geoffroy

Volume: 92Start Page: 26End Page: 2

The New Director of “the Spermatogonial Niche”: Introducing the Peritubular Macrophage

In this issue of Cell Reports, DeFalco et al. (2015) characterize a novel macrophage population associated with the peritubular lamina of mouse testes. These macrophages may create a niche not for the self-renewal of stem cells but rather the induction of their differentiation

Effect of estrogen deprivation on the reproductive physiology of male and female primates

The availability of CGS 16949A, CGS 20267 and CGP 47645, a series of aromatase inhibitors (AIs) having high specific activity and specificity, made possible this study wherein the need for estrogen (E) for regulating (a) follicular maturation/ovulation, luteal function and pregnancy establishment, and (b) testicular function of the bonnet monkey (Macaca radiata) has been examined. Generally these compounds, used in the range of 500 μg to 2.5 mg/day did not inhibit follicular maturation although they did reduce E levels. Although low doses had no effect on ovulation it appears that relatively high doses of CGS 20267 and CGP 47645 could be inhibiting it. Three oral doses of letrozole (CGS 20267, each dose of 2 mg) during the follicular phase resulted in the formation of multiple follicles in cycling females, and these could be ovulated by exogenous hCG (1000 IU) treatment. Although administration of AI during the early luteal phase had no effect on progesterone (P) production, it prevented pregnancy establishment. Whereas AI administration in the female had no significant effect on luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels (except at high drug dosages), it significantly increased serum testosterone (T) levels in the male. Sustained high levels of T (30-50 ng/ml) could be maintained for 100 days by administering 2.5 mg of CGP 47465 orally once in 5 days. Blockade of E synthesis in the male led to the disruption of testicular germ cell transformation, which in turn resulted in a significant reduction in sperm production. These studies with aromatase inhibitors in the monkey suggest that these compounds have a potential for use as fertility regulating agents in both the male and female primate

Effect of long-term treatment with aromatase inhibitor on testicular function of adult male bonnet monkeys (M-radiata)

The role/need for estrogen in regulating testicular function of adult male bonnet monkeys (M. radiata) has been investigated by dosing orally a group of five normal males 2.5 mgs of CGP 47645, a long-acting nonsteroidal aromatase inhibitor (AI), once every 5 days for over 150 days. Such treatment resulted in a 10-fold increment in nocturnal serum testosterone (T) levels, which were sustained for 85 days of treatment, and a twofold increment in basal serum T levels was present throughout the 150 days of treatment. Analysis of ejaculated semen showed a marked reduction (similar to 90%) in sperm counts in four out of five monkeys between Days 55-85 of treatment. During this period, the motility scare also was markedly reduced from a normal score of 3-5 to 0-2. Flow cytometric analysis of testicular germ cells obtained from biopsy tissue taken on Days 63 and 120 indicated a marked reduction only in elongating/elongated spermatid population (compared to Day 0 values), suggesting inhibition in spermiogenic process. Epididymal sperm maturation also seemed effected as sperm chromatin, on flow cytometric analysis for decondensability following exposure to 5 mM dithiotreitol, showed to be in a hypercondensed state. This study thus indicates that estrogen has an important role in providing normal testicular and sperm function in the primat

Fetal Radiation Exposure Induces Testicular Cancer in Genetically Susceptible Mice

The prevalence of testicular germ cell tumors (TGCT), a common solid tissue malignancy in young men, has been annually increasing at an alarming rate of 3%. Since the majority of testicular cancers are derived from germ cells at the stage of transformation of primordial germ cell (PGC) into gonocytes, the increase has been attributed to maternal/fetal exposures to environmental factors. We examined the effects of an estrogen (diethylstilbestrol, DES), an antiandrogen (flutamide), or radiation on the incidence of testicular germ cell tumors in genetically predisposed 129.MOLF-L1 (L1) congenic mice by exposing them to these agents on days 10.5 and 11.5 of pregnancy. Neither flutamide nor DES produced noticeable increases in testis cancer incidence at 4 weeks of age. In contrast, two doses of 0.8-Gy radiation increased the incidence of TGCT from 45 % to 100 % in the offspring. The percentage of mice with bilateral tumors, weights of testes with TGCT, and the percentage of tumors that were clearly teratomas were higher in the irradiated mice than in controls, indicating that irradiation induced more aggressive tumors and/or more foci of initiation sites in each testis. This radiation dose did not disrupt spermatogenesis, which was qualitatively normal in tumor-free testes although they were reduced in size. This is the first proof of induction of testicular cancer by an environmental agent and suggests that the male fetus of women exposed to radiation at about 5–6 weeks of pregnancy might have an increased risk of developing testicular cancer. Furthermore, i