In the domestic fowl, plasma concentrations of growth hormone (GH) have been observed to be elevated in young, rapidly growing chicks and low in older chicks and in adults. In this present study the plasma concentration of GH was high in 35-day-old male chickens and declined to the low adult concentration by 91 days of age. This decrease was observed in male chickens irrespective of whether they remained intact, were castrated at 35 days of age, or were castrated and implanted with testosterone. The plasma concentrations of GH in castrated birds were lower than those in the controls at 49 and 63 days of age. As would be expected, the plasma concentrations of luteinizing hormone (LH) were elevated by castration while testosterone implantation reduced the castration-induced rise in LH concentrations. Castration was followed by very low but detectable plasma concentrations of androgen. These were increased by testosterone implants.
All Science Journal Classification (ASJC) codes
- Animal Science and Zoology