Hollow fiber-encapsulated pituitary cells for the study of adenohypophyseal regulation of growth in poultry: 2. Recipient growth responses.
A technique for the encapsulation and transplantation of viable, functionally active adenohypophyseal cells to pituitary-intact poultry by means of hollow fiber units has been developed. Endogenous pituitary glands of broiler pullets that received high density capsules (1.2 X 10(6) cells) were observed 30 days after fiber implantation at 2 weeks of age. Glands were reduced in size and immunoreactive growth hormone (I-GH) concentration in comparison to sham and low density (.3 X 10(6) cells) groups. Although these changes were not significant, the combined reduction in mass and I-GH concentration equates to a 25 to 35% reduction in total pituitary I-GH content for the high density group, in comparison with sham and low density group birds, respectively. These changes suggest a feedback effect of high density cell implants on endogenous pituitary function. Relative gains of each group reflect apparent differences in pituitary I-GH content: high density group birds gained less than shams (P greater than .05) and significantly less than low density group birds. In a second study of older birds, cell implants (.73 X 10(6) cells) resulted in a significantly greater average relative gain (52%) in comparison with shams (33%) over the 6 week implantation period. Mixed adenohypophyseal cell populations transplanted to the hypophysiotropic region of pituitary-intact broiler pullets resulted in changes in endogenous pituitary function and growth of recipient birds. These studies suggest that dosage administered (e.g., cell density) may interact with age at application in determining the ultimate response of birds to exogenous manipulation of endocrine regulation of growth.
D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000254:growth & development*; D005260:Female; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology* / Q000502:physiology / Q000637:transplantation