Abnormalities of gonadotrophs in the adenohypophysis of infertile male PD rats

Male PD strain rats are sterile in the homozygous condition (pd/pd) due to abnormal spermatogenesis detectable at around nine weeks of age. Previous s tudies have indicated electron microscopic abnormalities in the Sertoli cel ls of pd/pd males at three and 12 weeks of age. Since spermatogenesis and S ertoli cell function depend on gonadotropins (luteinizing and follicle-stim ulating hormones [LH and FSH]) and testosterone, production and/or secretio n of these hormones might be altered in pd/pd males. The aim of the study r eported here was to investigate the hormonal status of pd/pd males at three , six, and nine weeks of age. Although alteration was not evident in the LH -immunoreactive cells, FSH-immunoreactive cells in pd/pd males were small i n size with scant cytoplasm and were reduced in number and area (73 and 51% of phenotypically normal pd/+ males, respectively) at three weeks of age, although serum FSH concentration was similar to that in pd/+ males. At six and nine weeks of age, percentages of the areas occupied by LH- and FSH-imm unoreactive cells in pd/pd males were higher than those in pd/+ males. Seru m FSH concentration in pd/pd males was significantly high at nine weeks of age, although a difference in serum LH and testosterone concentration was n ot evident. These results suggest that FSH production in pd/pd males is dec reased at three weeks of age. This might be associated with the Sertoli cel l abnormalities and subsequent abnormal spermatogenesis seen in adult life.