Reduction of long-term effects of local heating of the testis by treatmentof rats with a GnRH agonist and an anti-androgen

Heating the testes of anaesthetized adult rats to 43 degreesC for 30 min in a waterbath was followed by a large decrease in testis and epididymis mass and number of spermatozoa 35 days later. These parameters had recovered to some extent, but not completely, by days 70 and 97 after heating, but had decreased again in rats examined on day 182. There were no consistent effec ts of heating on androgen status, as determined by the concentrations of te stosterone in blood and testis fluids, or by seminal vesicle mass, and inte rstitial fluid volume was increased in the heated testes. Treatment of rats with an implant of a GnRH agonist and daily injections of an anti-androgen for 14 days (sufficient in itself to cause large temporary decreases in ti ssue mass, number of spermatozoa and androgen status) did not reduce the in itial decrease in testis mass or number of spermatozoa seen after heating, but reduced the later decreases in mass and number of spermatozoa significa ntly. These findings indicate that, as well as causing damage to spermatocy tes and spermatids, as previously reported, heating also reduces the abilit y of spermatogonia to repopulate the seminiferous tubules at longer interva ls after heating. Furthermore, it appears that this effect on the spermatog onia can be reduced by treating the animals with a GnRH agonist and anti-an drogen, a treatment similar to that shown by other authors to improve recov ery of the testis from irradiation or drug treatment.