Peroxidase Research Paper

Abstract: The possibility of ACTH being involved in the peroxidase -ascorbate system for the synthesis of progesterone.Rapid depletion of AA under the action of ACTH is known to be a donor in peroxidase reaction. Key Words: Adrenal, ACTH, Hypophysectomy,Peroxidase-Ascorbate System, Progesterone Introduction:
ACTH has a major role in the synthesis of progesterone which is known to be a precursor of several steroid hormones including androgens,estrogens and corticoids (Gorbman & Bern,1974).ACTH is also known to cause depletion of adrenal ascorbate and cholesterol in the hypophysectomized rat (Tyslowitz,1943; Sayers et al.,1946) which is shown to occur within minutes of ACTH injection and to exhibit a characteristic time sequence.Administration

(1962). Hypophysectomized immature female rats,80-100 gm weight were used in this study. 20µ of purified ACTH (Porcine-ACTH, Sigma Chemical Co., USA) dissolved in 0.5ml of physiological saline was administered to rats in a single dose by sub-cutaneous injection. The control group received physiological saline (0.9%) only which was administered to rats in a single dose by sub-cutaneous injection. Rats were sacrificed at different periods by cervical dislocation, dissected and the adrenals free of adhering fat were used for analysis. The tissues were stored at -200C after weighing whenever necessary. Out of the two adrenals in each animal, the left adrenal was analysed for peroxidase and the right for AA. Until & otherwise mentioned, five replicates at a time were used for each

ACTH induces the formation of peroxidase in the adrenal of hypophysectomized rats, which is associated with the depletion of asorbate. An inverse relationship is observed. Sayers et al., (1948) showed that depletion of ascorbate with ACTH in hypophysectomized rats exhibits a time pattern relationship; the depletion sets in within 5 minutes of ACTH injection,reaches a point of maximum depletion at about 1-2 hrs., whereafter the ascorbic acid concentration starts building up again, showing a rebound at about 20-24 hrs. High level of AA in adrenal has been suggested to act as a restraint factor on steroidogenesis particularly in the early reactions of the sequence involving cholesterol conversion to progesterone (Hayano,et al.,1956). It has been proposed that inhibition of steroidogenesis by AA is chiefly affected through hydroxylase system, which is relieved when stimulated by ACTH (Kitabachi,