THE POST-NUPTIAL OCCURRENCE OF PROGESTINS IN THE SEMINIFEROUS TUBULES OF BIRDS

Abstract

SUMMARY: It has been previously suggested that the cholesterol which appears during the post-nuptial metamorphosis of the seminiferous tubules of submammalian vertebrates may be of endocrine significance. It is now shown by means of paper chromatography that the tubular lipids of pigeons probably contain progesterone and its metabolites. The testes of control ('pre-nuptial') birds contain androgens but no progestins. Again, the Hooker-Forbes bioassay test indicates the presence of plasma progestins in seven out of eight birds with metamorphosed lipoidal tubules. Of seven control birds in full spermatogenesis six were negative for progestin. The possibility that the regular, post-nuptial accumulation and expenditure of tubular cholesterol is functionally homologous with the formation and regression of the corpus luteum is discussed.