Effect of oestradiol dipropionate on the immune system of the pigeon, Columba livia

Abstract

Influence of female sex hormone, oestradiol dipropionate on the humoral and cell-mediated immune (CMI) responses of pigeon, Columba livia of different age groups and of both sexes were studied. The pigeons were administered with the hormone, immunized with sheep red blood cells (SRBC) and rosette forming cell (RFC), haemagglutinin (HA) and migration inhibition (MI) assays carried out on different days post-immunization. The hormone showed a differential effect:while the RFC and HA were enhanced in 1-month old hormone administered female pigeons, they were normal in 3 or 4 month old birds. The MI response was however depressed in both age groups, and the thymus and bursa were involuted. The hormonal influence was marginal in males: the hormone administered 1-month old male showed an elevated RFC level. The three month old males showed a depressed MI. Among the lymphoid organs, the bursal weight was enhanced. It is thus evident that the influence of female sex hormone oestradiol dipropionate on the immune system depends on the age and sex of the pigeons, persumably because of the endogenous hormonal levels.