Action of ACTH1-24 upon plasma corticosterone concentrations in racing pigeons (Columba livia domestica)

To establish the optimal dose and sampling times for the ACTH stimulation test in racing pigeons, plasma corticosterone concentrations were measured in experimental animals at 0, 30, 60, 90, 120 and 150 min after intramuscular administration of different doses of ACTH(1-24). Baseline corticosterone concentrations varied between less than 0.2 and 1.24 microg/dl. To evaluate adrenocortical function the clinician is advised to take a blood sample before and at 60 or 90 min after stimulation with 50 microg ACTH or at 30, 60, 90 or 120 min after stimulation with 125 mug ACTH. In healthy individuals a ten- to hundred-fold increase over baseline (t=0) corticosterone concentrations and absolute concentrations in the range of 2.2 to 15.0 microg/dl can be expected in the post stimulation sample.

The turnover and distribution of labelled corticosterone during post-natal development of the duckling (Anas platyrhynchos)

During 6 months of post-natal development in the laboratory, the weight of the adrenal gland relative to body weight decreases exponentially. In the 3 day-old duckling a single intravenous dose of labelled corticosterone becomes distributed in a very large apparent volume and an "extracellular" pool that is greater than the extracellular fluid volume and the pattern of disappearance of labelled hormone from plasma is biphasic. Later during development the volumes of distribution decrease and the biphasic pattern of disappearance becomes less distinct until at 6 months only one phase of disappearance can be detected with confidence. No significant change in plasma corticosterone concentration occurs during this period of development in the laboratory. Estimations of the corticosterone secretory rates, however, indicate that whereas the adrenal weight-specific rate os secretion increases during the first 3 weeks and declines therafter, the bodyf weight-specific secretory rate continues to decline throughtout the period of increasing body weight.

The adrenal cortico-medullary ratio in the fowl

1. A new integrating method of assessing the proportions of cortical and medullary tissue in the avian adrenal gland is described and statistically evaluated. 2. It is shown that a single "central" section of the adrenal gland will suffice to obtain accurate results. 3. Each section was projected on to a grid of about 2500 intersection points and the ratio of points falling on cortical or medullary tissue was determined. 4. Applications of this method to normal fowls showed that there were significant breed, sex and, particularly, age differences in the cortico-medullary ratio of the fowl's adrenal glands.

Fine structure of the interrenal cell in the quail and the pigeon

The ultrastructural characteristics of the interrenal cell were investigated in the quail and the pigeon after fixation by intravascular abdominal perfusion. There is no significant fine structural difference between cells belonging to subcapsular and central regions of the gland. The interrenal cell in both species possesses nuclear bodies, polymorphic mitochondria with tubulo-vesicular cristae and tubular crystalline inclusions, considerable amounts of endoplasmic reticulum, ergastoplasm, a well developed Golgi apparatus, coated vesicles, microtubules, filaments, cilia, ribosomes, a profusion of liposomes, dense bodies with varied inner structure, pinocytic invaginations of cell membrane and intercellular attachment devices. The pigeon adrenorcortical cell also possesses intranuclear lipidlike inclusions and fibrous bundle (this being never recorded in adrenocortical cell), annulate lamellae, and a variety of cytosomes, probably lipofucsin in nature. The significance and cytophysiological role of various organelles and inclusions have been discussed in the light of earlier data obtained on avian adrenocortical cells.