Changes in the pituitary-testicular system with age

Multinucleate Sertoli cells in aged human testis

The present investigation documents morphological characteristics of human Sertoli cells of aged males. Testicular material was obtained from 35 patients (age 62-84 years) with carcinoma of the prostate who had received no previous anticancer therapy. As revealed by light and electron microscopy the appearance of the germinal epithelium showed great individual variations. In all cases examined, however, the occurrence of multinucleate Sertoli cells was a common finding. In seminiferous tubules with intact spermatogenesis these cells closely resembled the normally occurring variants, whereas they displayed features reminiscent of immaturity in the absence of germ cells. It is hypothesized that the nuclei of Sertoli cells in the special situation of aging may resume the capacity to divide, an ability normally restricted to immature cells. Thus, mitosis without subsequent cytokinesis might be an explanation for the formation of multinucleate Sertoli cells.

Effect of long-term physical training on plasma testosterone, androstenedione, luteinizing hormone and sex-hormone-binding globulin capacity

The effect of 6-months' physical training on plasma testosterone, androstenedione and luteinizing hormone levels and the binding capacity of sex-hormone-binding globulin (SHBG capacity) were studied in thirty-nine army recruits. Highly significant increases in mean plasma testosterone (21%), androstenedione (25%) and LH (25%) were observed during the training period and were associated with a mean 16% increase in the estimated maximal oxygen uptake. The mean increases in hormone levels tended to be greater in the well conditioned group than in the poorly conditioned group. The mean ratio of testosterone to SHBG capacity increased by 32% (P less than 0.05), which may be in relationship with the various training-induced effects.

Evaluation of plasma hormone concentrations in relation to clinical staging in patients with prostatic cancer. British Prostate Study Group

Plasma concentrations of testosterone, oestradiol-17 beta, luteinising hormone (LH), follicle stimulating hormone (FSH), prolactin and growth hormone (GH) were measured in patients with histologically proven prostatic cancer, before any form of therapy was given for this disease. Patients were categorised according to UICC classification. No systemic change in the group means of any of these hormones was associated with the progression of the disease from the T0 to the T4 stage. When multivariate analysis was applied to the combined intraprostatic (T0 + T1 + T2) and extraprostatic (T3 + T4) tumour category in patients without clinically evident metastases (M0) a discrimination was observed, GH substantially contributing to the separation of the 2 groups. When plasma hormone data from patients classified as M0 (without metastases) were compared with M1 patients (with metastases), mean GH values were significantly larger (P less than 0.02) in patients with metastases. GH was also a major contributory factor to the discrimination between the M0 and M1 groups, using multivariate analysis. Testosterone group means for M0 versus M1 were also significantly different (P less than 0.02).

Decline in sexual activity in ageing men: correlation with sex hormone levels and testicular changes

The menopause clearly marks the end of the reproductive phase in the female, but no comparable event of sudden discontinuity in fertility occurs in the male. Successful paternity in man has been recorded at the age of 94 (Seymour, Duffy & Koerner, 1935). This difference between the sexes is rather surprising, as the male does not seem to age in a fundamentally different way from the female and as, moreover, the death rate for males is higher in all age groups, than for females. This may be related to the presence of only one X chromosome, the eventual defects of which cannot be compensated for by the activity of the homologue. The Y chromosome does not appear to bear vital genes, as it is not essential for life, XO individuals being perfectly viable, in distinction to the YO genotype. Moreover in the absence of male inducers, the phenotype is female, suggesting that the male phenotype is a more complex differentiation. For whatever reason, the lower viability of the male remains a striking fact: males represent only 35% of the age group over 75 years. The persistence of reproductive function into old age is therefore the more surprising. This does not mean, however, that a gradual decrease in sexual activity and testicular function in the ageing male does not occur. From adolescence onwards, there is a continuous decline in sexual interest, arousal and activity, without a sudden discontinuity in any age group.

Sex steroids and sex-hormone binding globulin in males with chronic alcoholism

Thirty men with chronic alcoholism were studied. Biopsies of the liver and testis were performed in all. Serum concentrations of total and non-protein bound (free) testosterone and oestradiol, dihydrotestosterone and sex-hormone binding globulin (SHBG) were determined. Testosterone and dihydrotestosterone concentrations were normal in most patients, whereas oestradiol and free oestradiol were above normal in approximately 50% of the patients. None of the hormones measured differed significantly between patients with and without cirrhosis. SGBG was significantly higher in men with severely reduced spermatogenesis compared to those with intact germinal epithelium, but there was no difference between men with and without cirrhosis. No relation could be demonstrated between clinical signs of hypogonadism and any of the hormones measured. The results support the view that hormonal and sexual disturbances may occur in chronic alcoholism independent of the presence of liver disease.

Time of onset of sperm production in boys

Puberty is defined in the Oxford English Dictionary as the state or condition of having become functionally capable of procreating offspring, suggesting that it is a discrete event that occurs at a particular point in time. Whilst it is easy to determine the age at puberty in animals from the time of completion of spermatogenesis in the male, or the first ovulation in the female, these are particularly difficult criteria to evaluate in our own species. Thus human puberty is generally described in terms of a sequence of changes in secondary sexual characteristics occurring over an extended period of time, and these have been reviewed in detail by Marshall & Tanner (1974).

Fertility and the physician

Gonadal function in both sexes is under the synergistic control of the pituitary gonadotrophins, follicle stimulating hormone (FSH) and luteinising hormone (LH) which are in turn influenced both by the hypothalamus (via the gonadotrophin releasing hormone) and by feedback signals from the gonads. There is good evidence that such feedback is mediated by steroid hormones and by a product of the germinal epithelium, termed inhibin. A logical approach to reproductive disorders involves the localization of the primary disturbance either to the hypothalamo-pituitary unit or to the gonad, on the basis of history, physical findings and the results of hormone assays. In men, the majority of disorders leading to infertility are of unknown aetiology and cannot, therefore, be treated specifically. In women, anovulation is usually readily treatable and recent studies have emphasised the usefulness of prolactin assays and of specific treatment for hyperprolactinaemia in restoring ferility. Increased understanding of the mechanisms leading to infertility may provide valuable new approaches to fertility control.