IMMUNOREACTIVE ARGININE-VASOPRESSIN IN THE TESTIS - IMMUNOCYTOCHEMICAL LOCALIZATION AND TESTICULAR CONTENT IN NORMAL AND IN EXPERIMENTAL CRYPTORCHID MOUSE

The presence of arginine vasopressin (AVP)-like peptide(s) and AVP rec eptors has been previously demonstrated in the testis of several speci es. In this study we examined the immunocytochemical localization of A VP and of its associated neurophysin (NPII) within the mouse testis, a nd the testicular immunoreactive (IR)-AVP content in normal pubertal a nd adult mice and in unilaterally cryptorchid animals. Immunostaining was conducted on fresh frozen adult testicular sections and on culture d testicular cells using the avidin-biotin immunoperoxidase technique. Immunoreactivities for AVP and NPII were localized at the periphery o f the seminiferous tubules. Staining for AVP and NPII was reduced in t estes showing impaired spermatogenesis. AVP and NPII immunoreactivitie s were present in cultured Sertoli cells, but staining was undetectabl e in cultured Leydig cells. Negative controls were obtained by applyin g antiserum that had been preabsorbed with excess peptides in place of primary antiserum. Mouse testes were found to contain IR-AVP, which c o-eluted with synthetic AVP on HPLC and diluted in parallel in a speci fic RIA for AVP. Levels of IR-AVP expressed as pg/mg wet-weight testis were significantly higher (p < 0.05) in pubertal (36.6 +/ 1.5) than i n adult animals (27.4 +/- 1.5). Experimental unilateral cryptorchidism in adult animals resulted 2 wk later in a marked reduction (p < 0.01) in IR-AVP levels in the abdominal testis (18.1 +/- 1.0 pg/mg testis) as compared to the contralateral scrotal testis (29.8 +/- 1.1 pg/mg te stis).The present study provides, for the first time, information on t he probable site of production of IR-AVP in the mouse testis and indic ates that the testicular IR-AVP content is influenced by the maturatio nal and functional status of the testis. These results are consistent with a paracrine role for AVP-like peptide(s) in the regulation of tes ticular function.