effect of substance-p on galactopoietics hormones secretions and milk production and compositions

it has been well established that the secretions of thyroid hormones and growth hormone (gh) isunder the regulation of different neurotransmitters. the goal of this study was to determine whethersubstance-p, as a neurotransmitter, regulates the mean plasma concentrations of thyroxin (t4),triiodothyronine (t3), gh, milk amount and constituents in sanan goats. nine sanan goats were randomlydivided into 3 groups. each group received a daily infusion of either 1, 2 or 4 ug substance-p for 7 days intothe third ventricle. blood samples were collected daily for 11 days, and assayed for plasma t3, t4 and ghconcentrations by double-antibody ria. milk samples were collected daily for each of the 11 days. milksamples were assayed for protein, fat and lactose constituents. the daily amount of milk was determinedthroughout the experiment. infusions of 1 and 2 ug substance-p did not change the plasma concentrations of the t3, t4 and gh throughout the experiment. infusions of 4 ug substance-p significantly (p