RELATION BETWEEN THE ADRENALS AND THYROID AND THEIR HORMONES AND THE TESTICULAR CYCLE OF A SUBTROPICAL AVIAN SPECIES

In order to understand the hormonal interactions throughout the reprod uctive phases (non-breeding, progressive, breeding and regressive) of a sub-tropical avian species, the male common myna (Acriodotheres tris tis), hormones like epinephrine (E), norepinephrine (NE), corticostero ne, triiodothyronine (T-3), thyroxine (T-4) and testosterone (along wi th testicular sialic acid) were quantitated. Histometry and histology of the testis and adrenal glands were also performed. It became eviden t that a parallel relationship exists between the reproductive phases of the common myna and levels of the hormones E, NE, corticosterone, T -3, T-4 and testosterone. Considering the ambient climatological condi tions, it is suggested that primarily daylength and secondarily humidi ty control the gonadal cycle of this species.