AJP - Endocrinology and Metabolism, Vol 244, Issue 1 66-E71, Copyright © 1983 by American Physiological Society
Pituitary and testicular activity in chickens after embryonic testosterone treatment
R. L. Taylor Jr and B. Glick
This study was conducted to explain the lower circulating testosterone
levels in chickens exposed to testosterone propionate (TP) on the 3rd day
of incubation. Control and TP males were injected with either luteinizing
hormone (LH) or gonadotropin-releasing hormone (GnRH). Testosterone (T),
dihydrotestosterone (DHT), and LH were measured by radioimmunoassay. Levels
of circulating T in 20-wk-old TP males were significantly lower than
controls, but the response to GnRH was similar in both groups. LH levels
were also similar. Testosterone responses to LH in 20-wk-old TP males were
lower than controls, possibly due to their lower initial T concentrations.
Pituitary extracts from TP and control birds showed similar abilities to
induce testicular 32P uptake in day-old cockerels. The data demonstrate
that the anterior pituitary gland and testes of TP birds are capable of
responding to GnRH and LH, respectively. The TP males are defective in that
they fail to produce testosterone, which may reflect a reduced
concentration of LH receptors in their testes.
