Hormones and hormonal target cells in the testis

Integrated analysis of miRNA and mRNA expression profiles in testes of Landrace and Hezuo boars

Precocious puberty is closely related to testicular development and spermatogenesis, and there is increasing evidence that miRNAs are involved in regulation of testicular development and spermatogenesis. However, little is known about the regulation of microRNAs (miRNAs) during precocious maturation in Hezuo (HZ) boars. In this study, serum Testosterone (T), Estradiol (E₂), Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) levels were detected in HZ and Landrace (LC) boars in the postnatal period at 30, 90, 120, 180, and 240 days, and the testes of HZ and LC boars at 30 and 120 days were used for histological observation. In addition, we performed small RNA-Seq to identify miRNA at sexual immaturity (30-days-old) and maturity (120-days-old) of HZ boar testis (using LC boar as control) to reveal the key miRNA in regulation of precocious puberty. Hormone assay results showed that high levels of T, E₂, FSH, and LH may be related to precocious sexual maturity of HZ boars, and that FSH may play an important function before sexual maturity. Histological observation showed that HZ boars developed earlier than LC boars and had reached sexual maturity at 120 days. Small RNA-Seq yielded a total of 359 exist miRNAs, 767 known miRNAs and 322 novel miRNAs in 12 samples; 549, 468, 133, and 247 differentially expressed (DE) miRNAs were identified between Ha vs. Hb, La vs. Lb, Ha vs. La, and Hb vs. Lb (log₂ fold change >1 and p < 0.05). Enrichment analysis showed that target genes of these DE miRNAs were enriched in many gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways (such as PI3K-Akt, Hippo and Rap1 signaling pathways) were related to testicular development and spermatogenesis. Further screening, some miRNAs (such as ssc-miR-29b, ssc-miR-199b, ssc-miR-383, ssc-miR-149, ssc-miR-615, and ssc-miR-370) were possibly associated with precocious puberty. These results provide new light on miRNA regulatory mechanisms involved in precocious puberty.

Critical Roles of the Circadian Transcription Factor BMAL1 in Reproductive Endocrinology and Fertility

Brain and muscle aryl-hydrocarbon receptor nuclear translocator like protein1 (BMAL1), a core component of circadian oscillation, is involved in many physiological activities. Increasing evidence has demonstrated the essential role of BMAL1 in reproductive physiology. For instance, BMAL1-knockout (KO) mice were infertile, with impaired reproductive organs and gametes. Additionally, in BMAL1-KO mice, hormone secretion and signaling of hypothalamus-pituitary-gonadal (H-P-G) hormones were also disrupted, indicating that H-P-G axis was impaired in BMAL1-KO mice. Moreover, both BMAL1-KO mice and BMAL1-knockdown by small interfering RNA (siRNA) in vitro cultured steroidogenic cells showed that BMAL1 was associated with gonadal steroidogenesis and expression of related genes. Importantly, BMAL1 also participates in pathogenesis of human reproductive diseases. In this review, we elaborate on the impaired reproduction of BMAL1-KO mice including the reproductive organs, reproductive endocrine hormones, and reproductive processes, highlighting the vital role of BMAL1 in fertility and reproductive endocrinology.

Maternal folic acid supplement intake and semen quality in Danish sons: a follow-up study

OBJECTIVE

To examine whether maternal folic acid supplement intake during pregnancy is related to better semen quality in male offspring.

DESIGN

A follow-up study.

SETTING

Two major Danish municipalities, Aalborg and Odense.

PATIENT(S)

The study population included 347 singleton sons of mothers enrolled into the Healthy Habits for Two cohort when pregnant in 1984-87.

INTERVENTION(S)

Information on maternal folic acid supplement intake during pregnancy was provided by self-administered questionnaire in the 36th week of gestation.

MAIN OUTCOME MEASURE(S)

Semen characteristics and serum concentrations of sex hormones.

RESULT(S)

The distribution of semen characteristics among sons whose mothers took folic acid supplement during pregnancy (n = 88, 25%) did not differ from the distributions among those without (n = 75, 22%) or with unknown folic acid supplement intake (n = 84, 53%). On the contrary, serum levels of FSH and LH were significantly higher in the folic acid supplement group.

CONCLUSION(S)

The hypothesis that folic acid supplement intake during pregnancy will improve semen quality in male offspring was not corroborated by a follow-up study in young Danish men.

Histological changes in the testis of the domestic fowl after partial adenohypophysectomy

The effects of partial adenohypophysectomy on comb size, testicular weight, and histology 20 or 30 days after the operation are described and discussed in relating these observed changes with the volume of remaining adenohypophyseal tissue. From the present observation, it is concluded that 1) the response of the domestic fowl to partial deficiency of adenohypophyseal tissue may be more sensitive than that of some mammals, 2) the decrease in testicular weight and tubular diameter precedes the histological change in testis and comb regression, and 3) to maintain fully active testicular function, more than 75% of the adenohypophysis is needed. About 40% of the adenohypophyseal tissue including a remnant of cephalic lobe can stimulate spermatogenesis, but the spermatozoa produced were partially abnormal. The critical amount of adenohypophyseal tissue for normal spermiogenesis may exist between 55 and 75%. All histological change is initially observed in the center of testis and then extended toward the periphery. It is suggested that the cephalic lobe contains at least a trace of ICSH in addition to FSH.

Histological changes in the testis of the domestic fowl after adenohypophysectomy

Twenty-two cockerels were adenohypophysectomized by the improved transbuccal approach to observe histological changes in the testis during 60 postoperative days. Total adenohypophysectomy induced a collapse of spermatogenic cells and a decrease in the diameter of seminiferous tubules, accompanied by a rapid decrease in testicular weight. The patterns of degeneration of various spermatogenic cells were different from each other. Spermatozoa and spermatids were detached from the epithelium by day 5, spermatocytes by day 10, and more than half of spermatogonia by day 20 after the operation. Sertoli cells reduced their cytoplasmic processes on day 3 but still retained their height to sustain an indented form of epithelium between days 3 and 10, when most spermatogenic cells were disengaged from the epithelium. Sertoli cells were never sloughed off into the lumen. On and after day 20, seminiferous epithelium was monolayered, consisting of atrophied Sertoli cells with small sized nuclei and spermatogonia. Interstitial cells tended to agglomere maximum on day 60. Interstitium occupied more than 30% of estimated total volume of testis from day 20 onward. According to the observation on day 30, the degree of degeneration of seminiferous tubules in later stages depended on the location within the testis. The network of cytoplasmic processes of Sertoli cells persisted in the central but not in the peripheral region.

Local male hormonal therapy in male infertility: a preliminary report

The therapeutic effect of local infiltration of the testis by testosterone crystalline suspension was studied in 18 cases of severe oligozoospermia. Evaluation was done by semen analysis follow-up, and results were correlated with preoperative testicular biopsies. About 40% of the cases showed improvement of sperm count and/or motility. Testicular biopsies of responding cases showed mild inhibitory changes, such as sloughing or partial spermatogenic arrest at late stages, while cases with tubular hyalinization or spermatogenic arrest at the stage of spermatogonia showed no response. The method proved to be simple, safe, and promising.

Human testicular development and the role of the mesonephros in the origin of a dual Sertoli cell system

Some aspects of the development of the human testis (and overy) are discussed and the main theories regarding gonadal differentiation summarized. The major part of this review deals with the origin and differentiation of the three groups of somatic cellular content: Sertoli cells, Leydig cells and peritubular cells. The most important role of the mesonephros in gonadal development is described. Under the influence of the mesonephros, a second type of meiosis-inducing Sertoli cell differentiates and becomes the opponent of a meiosis-preventing type of Sertoli cell which derives from the coelomic epithelium. All somatic cells are pooled in the central gonadal blastema which is part of the medulla. They migrate via the rete blastema to the sites of their final differentiation. Included are the precursors of the Leydig cells and the peritubular cells.