Thesis (M.S.)--University of Montana, 2008. / Title from title screen. Description based on contents viewed Aug. 13, 2008. Includes bibliographical references (p. vi-xiv).

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--Ohio State University, 1965. / OSU's c.3 is a photocopy. Available online via OhioLINK's ETD Center

18-hydroxycorticosterone, aldosterone and corticosterone were positively characterized in duck adrenal incubates. A compound resembling 11-dehydrocorticosterone was also present. The addition of 1 I.U. of ACTH/100 mg of adrenal tissue caused an increase in the production rate of all four steroids. The most dramatic effect however, was observed with respect to the synthesis of corticosterone. Aldosterone-4-¹⁴C and 18-hydroxycorticosterone-4-¹⁴C were isolated from the media of adrenal glands incubated in the presence of a tracer amount of corticosterone-4-¹⁴C. During the incubation the maximum specific activity recorded for aldosterone-4-¹⁴C was 66% of the specific activity of the precursor. This observation indicated that the primary pathway to aldosterone in the duck adrenal was probably via corticosterone. 18-hydroxycorticosterone may be an intermediate between corticosterone and aldosterone or may be a distinct end product of unknown biological activity. No difference in the biological half-life (T₁/2) of corticosterone was found between fresh-water maintained fresh-water loaded birds and birds maintained on fresh water or saline and loaded with saline. An increase in the apparent volume of distribution (A.V.D.) of corticosterone was found however in saline loaded ducks. This resulted in an increased secretory rate of corticosterone in those animals loaded with saline. In the saline maintained ducks an increased adrenal size was responsible for the enhanced corticosterone secretory rate. In those ducks maintained on fresh water and loaded with saline a weight specific increase in the corticosterone secretory rate was apparent. The implications of the increased corticosterone secretory rate are discussed in relation to the known dependence of nasal gland function in marine birds on a functional adrenal cortex. / Science, Faculty of / Zoology, Department of / Graduate

Acid-base balance in plasma was studied in forcibly submerged Pekin ducks (Anas platyrhynchos). All important variables determining acid-base balance (arterial CO₂ tension (PαCO₂) strong ion difference ([SID]) and total protein content which approximates total weak acid concentration in plasma) were measured. During forced submergence PαCO₂ increased and pHa steadily decreased with time. There was also an increase in [lactate⁻], which was accompanied by an increase of equal magnitude in [Na⁺]. There were no significant changes in the concentrations of other strong ions (K⁺, Ca²⁺, Mg²⁺ and Cl⁻). Strong ion difference did not change during the first two minutes of submergence, but there was about a 4 mequiv/L increase by the end of the four-minute dive. Theoretically an increase in [SID] should cause plasma to be alkaline, but since plasma became progressively acidic, this condition can only be due to the increase in PαCO₂. During recovery from dives, the plasma remained as acidic one minute after emersion as at the end of the dives. On the other hand, arterial pH slowly increased towards the pre-dive level during recovery. Arterial CO₂ tension decreased much more rapidly and was already at or below the pre-dive level one minute after emersion. Therefore, PαCO₂ could no longer affect plasma pH. There was, however, a great increase in [lactate-] in the first minute of recovery. Although [Na⁺] and [K⁺] were elevated, from pre-dive values after the four minute dive, the increase in [lactate⁻] resulted in a marked reduction in [SID]. Since there was no change in the total plasma protein content, the acidic condition observed in recovery could only be due to decreased [SID]. Breathing 0₂ before diving prevented circulatory adjustments and pH returned to pre-dive levels one minute after emersion, confirming that the acidic condition observed in recovery is a consequence of the lactate produced in the hypoperfused tissues during submergence. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

No description available.

No description available.

No description available.