HUMAN PREPUBERTAL TESTICULAR CELLS IN CULTURE - STEROIDOGENIC CAPACITY, PARACRINE AND HORMONE CONTROL

The neonatal human Leydig cell undergoes a transient period of activat ion during the first months of life. The biological significance of th is activation is unknown. Furthermore, little is known about the hormo nal regulation of this biological process, even though it coincides wi th an elevation of LH levels in serum. In order to study the function of human prepubertal testicular culture cells, obtained during the neo natal period, a method for maintaining primary culture cells (isolated from testes collected at necropsy) in culture was developed. Within 2 4 h after death, testes were collected from 1-36-month-old subjects. S ubjects were divided into two age groups, based on the presence or abs ence of fetal Leydig cells: 1-7-month-old infants (group 1) and 12-36- month-old children (group 2). Testes were digested with collagenase, a nd cells were seeded in multi-well dishes. Cells were grown in serum-f ree conditioned media supplemented with 5 mg/l vitamin C, 0.2 IU/l vit amin E and 10% fetal bovine serum for 2 days. Cells were then grown fo r an additional 4 days in serum-free media in the presence or absence of hLH (40 IU/l), hCG (135 IU/l), rh FSH (1.5IU/l), rhGH (0.12 IU/l) o r insulin (0.9 mu mol/l). Concentrations of steroids in media were det ermined by RIA on day 6 of culture. In basal conditions cells of group 1 (n = 11) secreted more testosterone, androstendione, 17-hydroxyprog esterone, progesterone and dehydroepiandrosterone (mean +/- SE: 6.76 /- 1.86, 7.37 +/- 1.82, 61.9 +/- 1.86, 5.75 +/- 1.74 and 8.51 +/- 3.23 pmol/10(6) cells/24 h, respectively) than cells of group 2 (n = 5) (2 .95 +/- 1.15, 1.50 +/- 2.75, 1.44 +/- 2.75, 0.78 +/- 1.74 and 3.23 +/- 1.32, respectively). Under hLH stimulation, cells of group 1 increase d testosterone, androstendione and 17-hydroxyprogesterone secretions ( to 38.2 +/- 0.89, 13.5 +/- 1.17 and 51.7 +/- 3.23), while progesterone secretion remained unchanged (2.82 +/- 1.20). Cell response to rhFSH and rhGH was similar to that of hLH. On the other hand, medium collect ed from cultures of cells isolated from a Sertoli cell tumor was able to stimulate testosterone secretion in subcultures of control testicul ar cells in a way similar to that of hCG. In conclusion, (1) these pre pubertal human testicular cells can be maintained in primary culture f or several days keeping their in vivo steroidogenic potential; (2) cel ls isolated from young infants can respond to hLH in culture; (3) resp onse to rhFSH is probably mediated by a paracrine factor; (4) response to rhGH is observed in the absence of gonadotropins. Therefore, the e arly postnatal activation of the human testis might be under multiple pituitary hormone control; and, finally, (5) Sertoli cell tumors can s ecrete paracrine factors that stimulate steroidogenesis.