Abstract
The relative proportions of adrenaline (A) and noradrenaline (NA) containing celluler areas have been planimetrically estimated in the twelve avian species representing several orders and families. The study reveals a great variability in percentages of A and NA-containing cells in the suprarenal medulla of these species. Three possibilities have been forwarded to explain this hormonal diversity. These are. i) methylation of medullary hormones is dependent on the cortico-medullary ratio, ii) relative abundance of A and NA in a species is determined by the degree of aggression and predation behavior manifested by it and iii) differing association of A and NA in this class of vertebrates may bear some relation to the suggested avian phylogeny. Amongst these probabilities, the last one appears to fit in rather closely to our data. This assumes an efficacious accomplishment or hormonal methylation in the course of avian evolutionary ascent.The present report also indicates that the chromaffin tissue of birds under investigation is rich in acetal phosphatides, metachromatic substances and acid phosphatase. Two species (H. smyrnensis and A. phoenicurus), however, fail to reveal any trace of medullary metachromatic materials. This as well as the concept of ‘basic cytochemical unit’ in avian adrenal medulla have been pointed out and briefly discussed.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
