Age dependence of testosterone precursors in plasma of normal adult males

Cytoplasmic steroid receptors in tumoral and "normal" endometrial samples from symmetrical uterine zones

Cytosol progesterone (PgR) and estradiol (E2R) receptors were quantified simultaneously in "normal" and tumoral endometrium samples, located symmetrically on the longitudinal axis of the uterine cavity. With this experimental model two different groups of patients were detected. In the first group (7 of 10 women), the endometrial carcinoma had a greater cytosolic concentration of PgR than the corresponding "normal" endometrium, both kinds of tissue being affected by the same circulating hormonal "environment," peculiar to each patient. The opposite occurs in the other group (3 of 10 women), since the "normal" endometrium was found to be "richer" in receptors than the tumoral endometrium. It is suggested that this difference in the capacity of the tumor for synthesizing PgR and even E2R as compared to the "normal" endometrium may be a marker which improves selection of patients who will be more likely to respond favorably to endocrine therapy.

Decrease of circulating level of SHBG in postmenopausal obese women as a risk factor in breast cancer: reversible effect of weight loss

Levels of circulating estrone (E1), estradiol (E2), androst-4-ene-3,17-dione (Adione), 3,5,3'-triiodothyronine (T3), thyroxine (T4), and sex hormone-binding globulin (SHBG) were measured in 10 obese postmenopausal patients with breast cancer and in 10 obese postmenopausal control subjects matched for age, body size, and menopausal status. T3, T4, and SHBG were also measured in 10 lean postmenopausal control subjects. In cancer patients after mastectomy, the cytosolic estrogen receptors (E2R) in tumor specimens were determined. No significant differences between the two groups of obese postmenopausal women were found for levels of all determinations carried out in serum. Comparing obese subjects (with or without breast cancer) with lean controls, circulating levels of T3 were found approximately 50% higher in the obese group. Conversely, SHBG was found around 50% of the value observed in lean controls. The changes presumably produced by obesity on serum SHBG levels appear to be reversible, tending toward normality with weight reduction. In cancer patients SHBG correlated negatively with cytosolic E2R concentrations (P less than 0.01). In conclusion, it is considered that obesity implies a double risk for breast cancer in susceptible postmenopausal women, by inducing a decrease of SHBG and a concomitant increase of the supply of "free" E2 to target tissues, in absence of cyclic endogenous progesterone.

Testicular function and sexual activity in senescent mice

The steroidogenic potentials of testes from 6-mo-old and approximately 28-mo-old CB6F1 mice were compared by measuring the secretion rate of 11 steroids produced by testes perfused in vitro. Testes from 6- and 28- to 30-mo-old mice secreted similar amounts of testosterone, but marked differences in the secretion of testosterone biosynthetic intermediates were discovered. Testes of old mice produced significantly more (P less than 0.01) delta 5-steroids than young male mouse testes. The presence or absence of sexual activity among old male mice was not correlated with changes in testicular steroidogenesis or plasma steroid levels. The results suggest that selected alterations in androgen biosynthesis occur during aging, but that the decline in reproductive performance among old mice is not attributable to deficits in testicular steroidogenesis. Rather, age-associated losses in sexual activity may be mediated by disturbances in the central nervous system.

Andropause: incidence and pathogenesis

One hundred forty-five male volunteers, 60 to 91 years old, without any hepatic, renal, or metabolic pathology, and not under any steroid therapy for at least 1 year were studied. Plasma luteinizing hormone (LH), Follicle Stimulating hormone (FSH), Testosterone (T), 17-beta-Estradiol (E2), Androstenedione (A), Maximal increase (MI) of LH and FSH after luteinizing hormone releasing hormone (LHRH) (50 gamma iv), and pulsations (P) of LH and FSH over a 3 hr period were measured by radioimmunoassay (RIA). The patients were divided in four groups according to LH and T levels. Group I: (46% of our subjects) showed no signs of hypogonadism with normal LH, T, E2, A, MI of LH and FSH, and normal P-LH, P-FSH. Group II: (15%) with high LH but normal T, showed high FSH, MI-LH, MI-FSH, P-LH, and P-FSH, but normal A and E2. Group III: (22%) with classical signs of hypergonadotropic hypogonadism (high LH and low T) showed high FSH, MI-LH, MI-FSH, and P-FSH, normal P-LH and E2, but low A. Group IV: (16.5%) with signs of hypogonadotropic hypogonadism (low LH and low T) had also low MI-LH, MI-FSH and A, but normal FSH, P-LH, P-FSH, and E2. Contrarily to menopause in women, andropause is not an obligatory event in men, and when it does occur, its pathogenesis and hormonal aspects are very variable.

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.

Attrition of the human Leydig cell population with advancing age

Existing evidence suggests that the aging human male experiences a gradual decline in testosterone production, a phenomenon that should be reflected in the Leydig cell population of the testis. It has been proposed that Leydig cells diminish in number with increasing age, but conflicting claims characterize reports of this topic. We have reinvestigated this possibility by histometric analysis of perfused testes from 25 men ranging from 18 to 87 years of age. Average single Leydig cell volume (2,943 +/- 623 micrometer 3, X +/- S.D.) did not change significantly with increasing age (r = 0.24, P greater than 0.2), suggesting that surviving cells remain active. Total testis weight (43.5 +/- 13.9 g) also did not change with age (r = 0.04, P greater than 0.5). However, both total Leydig cell volume and the absolute number of Leydig cells per individual decreased significantly as functions of age (r = -0.71, P less than 0.002, and r = -0.61, P less than 0.005, respectively). Analysis of relationship between these two parameters indicates that the total volume of Leydig cell cytoplasm contained within the human testis is determined by the number of cells present. Our results show that a pair of young adult testes endowed with more than 700 million Leydig cells at 20 years of age may be expected to undergo an attrition rate of approximately 80 million cells per subsequent decade of life. Thus, Leydig cell attrition is an important correlate of declining androgen status in aging men.