Human testicular secretion with increasing age

In Vitro Conversion of3H-Pregnenolone by Human Testicular Tissue from Fetal Age to Senescence

“…Decreased concentrations of testosterone in peripheral and spermatic venous blood compared with the concentrations found in younger adult males have been reported in elderly men [ 14,16,20,31 1. This may be due to a primary testicular insufficiency as well as the presence of a hypothalamic-pituitary disorder of gonadotropin secretion associated with the aging process [31].…”

“…High intratesticular concentrations of testosterone are necessary for normal spermatogenesis [24] . Many authors have reported that testicular testosterone secretion decreases with age [14,17,20,301, while others have refuted this theory [9]. LH seems to be the most important regulator of testicular steroid production through the induction or activation of enzymes responsible for androgen biosynthesis [29] .…”

Impaired in vitro Testicular Endocrine Function in Elderly Men

“…Many authors have reported decreased peripheral and spermatic venous testosterone concentrations in elderly men (Lewis et al -1976;Nieschlag -1979;Serio et al -1979;Mastragiacomi et al -1982). Testosterone secretion, however, was found to be preserved in a group of healthy, elderly men (Harman and Tsitouras -1980).…”

“…Based on measurements in peripheral or spermatic venous blood, testicular testosterone secretion has been reported to decrease with age (Lewis et al -1976;Nieschlag -1979;Serio et al -1979;Mastragiacomi et al -1982). It has also been reported that the circadian variation of the testosterone secretion found in normal young males was markedly attenuated or even absent in healthy elderly men (Bremner et al -1983).…”

Lessons learned in andrology: from endocrinology to andrology and backwards: the round trip of a clinician

“…In collaboration with some surgeons we used these methods to measure the concentration of testosterone and other steroids in the spermatic venous blood drawn during surgery for undescended testis and inguinal hernia in pre‐pubertal boys and adult men, respectively. In summary after my degree in Medicine my work was mainly dedicated to assay methods and then to the study of Leydig cell function of the human testis (Serio et al ., ). In 1980 Mario Serio was appointed Full Professor of Andrology in the University of Sassari in Sardinia and three years later he moved to Florence.…”