[Development of blood testosterone in the embryo and young chick after precocious bursectomy].

The effect of bursa of Fabricius on the endocrine function of the chick testes was studied in vivo by comparing plasma testosterone levels from 48 h before hatch to 16 weeks of age in both intact and bursectomized chicken. Early bursectomy was performed at 80 h of incubation. Post surgery survival was low (12% at 1 week). In controls, plasma testosterone levels were found to be low (100-200 pg. ml-1) from 48 h before to 48 h after hatch, then to raise up to a plateau (2,200 pg. ml-1) at 6 weeks. After bursectomy, values were first higher than in intact (210-440 pg. ml-1 from 48 h before/after hatch and 515 vs 300 pg.ml-1 at 3 days) but no difference could be further detected from 1 to 16 weeks of age. It is suggested that, in addition to the effect of androgen on bursa of Fabricius, the later reciprocally influences the gonadotropic axis during the early stage of development.