title: Recombinant human follicle-stimulating hormone is capable of exerting a biological effect in the adult hypophysectomized rat by reducing the numbers of degenerating germ cells.
abstract: There is considerable controversy as to whether FSH can, under normal circumstances, exert an effect to promote spermatogenesis in the adult rat. Recombinant human FSH (rhFSH) was used to answer a more limited question relating to whether FSH is capable of exerting a biological effect in promoting adult spermatogenesis. Can a pure preparation of FSH prevent the regressive changes seen after hypophysectomy (Hx) in a short term experiment? To answer this question, five groups of adult rats were used as follows: pituitary-intact animals, 3-day hypophysectomized (Hx), 3-day Hx given 3 mg testosterone propionate (T)/day for 7 days, 3-day Hx given 22 IU rhFSH for 7 days, and 3-day Hx given saline vehicle for 7 days. Testis weight, seminiferous tubule diameter, analysis of four degenerating germ cell types, the relative amount of lipid, and the levels of FSH receptors showed that FSH could, in a significant manner, prevent the regressive changes accompanying Hx. FSH was not as effective as T in doing so, because the FSH values were always intermediate between T-maintained animals and those after long term Hx. The Leydig cell was eliminated as a possible source of FSH-stimulated T promotion of spermatogenesis, given that morphometry and tissue T assays indicated that no additional production of T was elicited by rhFSH. The assay system used to enumerate degenerating germ cells proved a very sensitive indicator of the ability of hormones to maintain cell viability in short term experiments. The data not only show that FSH can exert a biological effect, but that this effect is qualitatively similar to that seen after the administration of T in terms of the maintenance of viability of specific germ cell types. A hypothesis is presented whereby FSH and T, although the former acting by a second messenger system and the latter by binding to nuclear receptors, can stimulate the genome to exert similar qualitative effects promoting the viability of germ cells.
authors.affiliation: Department of Physiology, Southern Illinois University School of Medicine, Carbondale 62901-6512.
authors.forename: L D
authors.initials: LD
authors.lastname: Russell
authors.forename: T J
authors.initials: TJ
authors.lastname: Corbin
authors.forename: K E
authors.initials: KE
authors.lastname: Borg
authors.forename: L R
authors.initials: LR
authors.lastname: De França
authors.forename: P
authors.initials: P
authors.lastname: Grasso
authors.forename: A
authors.initials: A
authors.lastname: Bartke
mesh_terms: D000818:Animals; D005640:Follicle Stimulating Hormone / Q000378:metabolism / Q000494:pharmacology*; D007016:Hypophysectomy; D007985:Leydig Cells / Q000166:cytology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D012671:Seminiferous Tubules / Q000033:anatomy & histology / Q000187:drug effects; D013076:Sperm Count; D013091:Spermatogenesis / Q000187:drug effects*; D013094:Spermatozoa / Q000166:cytology* / Q000187:drug effects; D013737:Testis / Q000033:anatomy & histology / Q000187:drug effects; D013739:Testosterone / Q000378:metabolism / Q000494:pharmacology
chemical_list: D011994:Recombinant Proteins; D013739:Testosterone; D005640:Follicle Stimulating Hormone