| Title: |
Gonadotrophins regulate germ cell survival, not proliferation, in normal adult men. |
| Authors: |
Saleela M. Ruwanpura; Robert I. McLachlan; Kati L. Matthiesson; Sarah J. Meachem |
| Source: |
Human Reproduction; Feb2008, Vol. 23 Issue 2, p403-403, 1p |
| Subject Terms: |
Gonadotropin; Germ cells; Cell proliferation; Spermatogenesis |
| Abstract: |
BACKGROUND Gonadotrophins support spermatogenesis via poorly understood mechanisms. We aimed to determine the effect of FSH/LH suppression in regulating germ cell apoptosis and proliferation in normal fertile men. METHODS Testicular tissues were obtained after gonadotrophin suppression induced by testosterone alone or combined with depot medroxyprogesterone acetate for 2 or 6 weeks and an untreated group of men (referred to as ‘normal men’) served as controls (n = 5 or 10 men per group). Apoptosis and proliferation were identified by terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) and proliferating cell nuclear antigen (PCNA) labelling methods, respectively. Intrinsic and extrinsic apoptotic pathways were identified by immunohistochemistry using the pathway-specific proteins: activated caspase (aCaspase) 9 and 8 and quantified using stereological techniques. RESULTS By 2 and 6 weeks, the proportion of TUNEL-labelled spermatogonia increased to 354% and 268% respectively, compared with normal men (P P P = 0.06), respectively. The proportion of TUNEL-labelled elongating/elongated spermatids tended to increase (144 and 138% compared with normal men, NS) at 2 and 6 weeks, respectively, with no change in either caspase immunoreactivities. Even though the number of PCNA-labelled cells did not change with gonadotrophin suppression, the balance between proliferation and apoptosis was lower in spermatogonia (P = 0.01) and spermatocytes (P = 0.3) between treated and untreated normal men. CONCLUSIONS We demonstrated that gonadotrophins act as spermatogonial survival factors via the regulation of intrinsic apoptotic pathway, whereas having no effect of cellular proliferation in normal men. [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |