The mineralocorticoid pathway starts with 21-hydroxylation of progesterone to form deoxycorticosterone (DOC). The enzyme in this reaction, 21-hydroxylase, is encoded by the CYP21 gene. 11 , 12 Deoxycorticosterone is then converted to corticosterone through the action of 11β-hydroxylase. There are two distinct 11β-hydroxylase isoenzymes, both of which are encoded by two genes, CYP11B1 and CYP11B2 . 13 Corticosterone is hydroxylated at carbon 18 to form 18-hydroxycorticosterone, which is transformed to aldosterone by removal of two hydrogens (oxidation) at carbon 18. These two reactions are catalyzed by 18-hydroxylase and 18-hydroxysteroid dehydrogenase, respectively, which are encoded by the same gene, CYP11B2 . Transcription of CYP11B1 is regulated primarily by ACTH, whereas angiotensin II regulates CYP11B2 transcription. 14 , 15 Similarly, the glucocorticoid pathway begins with 17α-hydroxyprogesterone, which is converted to deoxycortisol and subsequently to cortisol by 21-hydroxylase and 11β-hydroxylase, respectively, in the same manner as the conversion of progesterone to corticosterone. A deficiency of 21-hydroxylase, 11β-hydroxylase, or 3β-HSD in the adrenals may result in congenital adrenal hyperplasia and female pseudohermaphroditism, manifested as a masculinized female fetus.
All you meat lovers will be glad to hear Dr. Thomson say that steroid implants have no effect on beef quality, according to published research. More importantly, though, the meat is safe. The technology has been used since 1954 and there are strict guidelines and regulations in place to assure that neither human health nor animal health is negatively impacted. When compared to meat and milk that come from animals raised without hormones, the difference is…there is none. The USDA, the Academy of Nutrition and Dietetics and the Journal of Clinical Nutrition have all stated that beef from natural and organic programs is not safer, more nutritious, more wholesome or different in appearance compared to beef from animals that have received steroid implants. Aside from cooking the burgers at your next barbecue to the proper internal temperature , there’s no need for you to stress about the quality of regular beef and hormone-free beef!
SEE ALSO Adrenal Gland ; Amino Acid ; Blood Sugar Regulation ; Endocrine System ; Female Reproductive System ; Homeostasis ; Hypothalamus ; Male Reproductive System ; Nucleotides ; Pancreas ; Pituitary Gland ; Thyroid Gland ; Transcription