Control of spermatogenesis by follicle stimulating hormone and testosterone

Fshb Knockout Mouse Model, Two Decades Later and Into the Future

In 1997, nearly 20 years ago, we reported the phenotypes of follicle-stimulating hormone (FSH) β (Fshb) null mice. Since then, these mice have been useful for various physiological and genetic studies in reproductive and skeletal biology. In a 2009 review titled "FSHβ Knockout Mouse Model: A Decade Ago and Into the Future," I summarized the need for and what led to the development of an FSH-deficient mouse model and its applications, including delineation of the emerging extragonadal roles of FSH in bone cells by using this genetic model. These studies opened up exciting avenues of research on osteoporosis and now extend into those on adiposity in postmenopausal women. Here, I summarize the progress made with this mouse model since 2009 with regard to FSH rerouting in vivo, deciphering the role of N-glycosylation on FSHβ, roles of FSH in somatic-germ cell interactions in gonads, and provide a road map that is anticipated to emerge in the near future. Undoubtedly, the next 10 years should be an even more exciting time to explore the fertile area of FSH biology and its implications for basic and clinical reproductive physiology research.

Male germ line stem cells: from cell biology to cell therapy

Research using stem cells has several applications in basic biology and clinical medicine. Recent advances in the establishment of male germ line stem cells provided researchers with the ability to identify, isolate, maintain, expand and differentiate the spermatogonia, the primitive male germ cells, as cell lines under in vitro conditions. The ability to culture and manipulate stem cell lines from male germ cells has gradually facilitated research into spermatogenesis and male infertility, to an extent beyond that facilitated by the use of somatic stem cells. After the introduction of exogenous genes, the spermatogonial cells can be transplanted into the seminiferous tubules of recipients, where the transplanted cells can contribute to the offspring. The present review concentrates on the origin, life cycle and establishment of stem cell lines from male germ cells, as well as the current status of transplantation techniques and the application of spermatogonial stem cell lines.

Congenital estrogen deficiency: in search of the estrogen role in human male reproduction

Recently, a remarkable progress has been made in our understanding about the role of sex steroids in male physiology. In this paper, we consider the clinical aspects of congenital estrogen deficiency - notably, estrogen resistance and aromatase deficiency - in men and we discuss both well-established and supposed estrogen roles in the human male reproductive function. These topics include the role of estrogens in the control of gonadotropin secretion, in male fertility determination and psychosexual behavior. Briefly, estrogens play a pivotal role in the control of serum gonadotropin concentrations in the human male. Furthermore, a possible role of estrogens on both human male fertility and sexuality has also been suggested by recent studies, even though the available data are far from being conclusive. Conversely, for what concern fertility and sexual behavior, a well-established effect of estrogens has been provided by recent studies on male rodents, which show impaired sexual behavior and fertility as a consequence of estrogen defect.

Vectorial production of interleukin 1 and interleukin 6 by rat Sertoli cells cultured in a dual culture compartment system

The bidirectional production of interleukin-1 (IL-1) and IL-6 by Sertoli cells and its regulation by inflammatory and physiological stimuli has been studied using a dual compartment culture system allowing the study of Sertoli cell apical and basal secretory activities. Another Sertoli cell activity, the vectorial transferrin production was also studied in all culture conditions. A low constitutive IL-1 production appeared equally distributed between both poles, while IL-6 and transferrin constitutive production was predominantly directed apically. Two activators of macrophages, lipopolysaccharides and zymosan, were found to induce marked increases of IL-1 in the compartment where they had been added: basal if added to the lower compartment and vice versa. In contrast, after a basal stimulation, IL-6 production was mainly increased in the upper compartment that corresponds to a Sertoli cell apical flux. In this system, IL-1 and IL-6 levels were not modified by FSH; they were not also affected by residual bodies and latex beads, probably due to the fact that, in the bicameral system, phagocytosis is restricted to the Sertoli cells situated at the surface of the inner compartment. IL-1beta, but not IL-1alpha, induced IL-6 secretion in the compartment of stimulation. In conclusion, the present study demonstrates that vectorial secretory patterns of IL-1 and IL-6 production greatly differ and that these cytokines are also differently regulated. These results suggest that Sertoli IL-1 and IL-6 have different targets within the testis and that, in normal and pathophysiological conditions, both the tubular and the interstitial compartments may be influenced by the action of these paracrine factors.

High dose testosterone therapy for reduction of final height in constitutionally tall boys: does it influence testicular function in adulthood?

OBJECTIVE

We have studied the effect of treatment with high doses of androgens during puberty on testicular function in adult men with constitutionally tall stature, taking into account confounding factors interfering with sperm quality, since existing published data do not include whether testicular function is impaired by such treatment.

DESIGN

Historical cohort study.

PATIENTS

Forty-three previously androgen treated tall men (cases) and 30 non-treated tall men (controls).

MEASUREMENTS

Physical examination, semen analysis and plasma levels of LH, FSH, testosterone (T), sex hormone binding globulin (SHBG) and inhibin.

RESULTS

Sperm quality and testis volume were comparable between cases and controls. Mean sperm concentration was 66.4 x 10(6)/ml in cases and 66.2 x 10(6)/ml in controls. A left-sided varicocele was found in 45% of the cases and 37% of the controls. In cases we observed a significant effect of the age at start of androgen therapy on sperm motility (regr. coeff. (SE): 4.92 (2.41)%, P = 0.048). In addition, testicular size at start of therapy had a significant effect on sperm concentration (regr. coeff. (SE): 5.57 (1.54) x 10(6)/ml, P = 0.0012) and on total sperm count (regr. coeff. (SE): 43.1 (7.73) x 10(6), P = 0.0001). Plasma levels of T, SHBG and inhibin were not statistically different between the groups. Cases had significantly higher FSH levels (mean (SD) 3.3 (2.2) vs 2.1 (0.8) IU/I, P = 0.004) and significantly lower LH levels (mean (SD) 2.3 (0.9) vs 3.1 (1.4) IU/I, P = 0.019). We found a significant effect of age at start of therapy on plasma FSH level in the treated men (regr. coeff. (SE): -0.73 (0.18) IU/I, P = 0.0003).

CONCLUSIONS

Treatment with high doses of androgens for reduction of final height in constitutionally tall stature has no long-term side-effect on sperm quality, testicular volume or plasma testosterone levels. However, treated men had significantly higher plasma levels of FSH compared with controls. The meaning of this difference remains to be established. Varicocele was present in 42% of the adult tall men.