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cAMP Plasma cyclic adenosine monophosphate (cAMP) has been found to be elevated in some autistic children (Hoshino, 1980; Cook, 1990), but platelet investigations have not found the same results (Berry-Kravis, 1993). Cyclic AMP production was not statistically different from controls in platelets of patients with mental retardation or autistic disorder (Berry-Kravis, 1993). A diminished cAMP production exists in platelets from patients with fragile X syndrome (Berry-Kravis 1995, 1993, 1992). Results obtained from a group of patients with fragile X suggest possible abnormal function or regulation of the catalytic subunit of adenylate cyclase in patients with fragile X (Berry-Kravis, 1992). Diminished cAMP also exists in the blood platelets from schizophrenic patients (Kafka, 1979). Rat experiments have shown that the amount of fluoride required for adenylate cyclase activation in thyroid pathology is IDENTICAL to the one at which fluoride causes dental fluorosis when the catalytic subunit of adenylate cyclase is present (Clark, 1985; Jenq et al, 1993). Elevated plasma cAMP levels are usually seen in hyperthyroidism, while in hypothyroidism levels do not significantly differ (Peracchi et al, 1983). Significantly positive correlations between plasma and urinary levels of both cyclic AMP and cyclic GMP and the serum thyroid hormone levels and plasma and urinary cyclic nucleotide concentrations were also found, suggesting that the elevated extracellular cyclic nucleotide levels in hyperthyroidism are probably a consequence of increased secretion of thyroid hormones - the result of elevated TSH. Nagasaki et al (1985) showed that both serum cyclic AMP phosphodiesterase (cAMP-PDE) and cyclic GMP phosphodiesterase (cGMP-PDE) activities measured in a low substrate concentration were elevated 3-fold in subacute thyroiditis and slightly in hyperthyroidism, compared to the normal patients. Slight decreases of these enzyme activities were observed in primary hypothyroidism. PDE activities were positively correlated with the value of T3-RSU and serum thyroid hormone levels in hyper- and hypothyroidism. This enzyme activity increased in the kidney cortex from hypothyroid rats and reverted to the normal level after the subcutaneous administration of T3 daily for 3 days (Hagino et al, 1980). Incidentally, cAMP levels (as has GSH) have been chosen to be an indicator in blood chemistry relating to different states of chronic fluorosis (Guan, 1991). ================================ Berry-Kravis E, Sklena P - "Demonstration of abnormal cyclic AMP production in platelets from patients with fragile X syndrome" Am J Med Genet 45(1):81-7 (1993) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=8380312&form=6&db=m&Dopt=r Berry-Kravis E, Huttenlocher PR - "Cyclic AMP metabolism in fragile X syndrome" Ann Neurol 31(1):22-6 (1992) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=1371909&form=6&db=m&Dopt=r Berry-Kravis E, Hicar M, Ciurlionis R - "Reduced cyclic AMP production in fragile X syndrome:cytogenetic and molecular correlations" Pediatr Res 38(5):638-43 (1995) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=8552427&form=6&db=m&Dopt=r Clark OH, Gerend PL - "Thyrotropin regulation of adenylate cyclase activity in human thyroid neoplasms" Surgery 97(5):539-46 (1985) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=2986305&form=6&db=m&Dopt=r Cook EH - "Autism: review of neurochemical investigation" Synapse 6:292-308 (1990) Guan ZZ - "An experimental study of blood biochemical diagnostic indices for chronic fluorosis" Chung Hua Yu Fang I Hsueh Tsa Chih 25(1):33-5 (1991) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=2036910&form=6&db=m&Dopt=r Hagino Y, Uematsu T, Tachibana M, Tsuru H - "Effect of thyroid hormone on cyclic AMP phosphodiesterase in rat kidney" Jpn J Pharmacol 30(4):521-8 (1980) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=6162987&form=6&db=m&Dopt=r Hoshino Y, Kumashiro H, Yashima Y, Kaneko M, Numata Y, Oshima N, Watanabe A - "Plasma cyclic AMP level in psychiatric diseases of childhood" Folia Psychiatr Neurol Jpn 34(1):9-16 (1980) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=6248442&form=6&db=m&Dopt=r Jenq SF, Jap TS, Hsieh MS, Chiang H - "The characterization of adenyl cyclase activity in FRTL-5 cell line." Chung Hua I Hsueh Tsa Chih (Taipei) 51(3):159-65 (1993) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=8387868&form=6&db=m&Dopt=r Kafka MS, van Kammen DP, Bunney WE Jr - "Reduced cyclic AMP production in the blood platelets from schizophrenic patients" Am J Psychiatry 136(5):685-7 (1979) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=219720&form=6&db=m&Dopt=r Nagasaka A, Hasegawa H, Hayami S, Hidaka H, Tanaka T, Niinomi M, Nihei N, Nakagawa H, Ohyama T, Aono T, et al - "Serum cyclic 3',5'-nucleotide phosphodiesterase in patients with various thyroid disorders" Enzyme 33(1):18-24 (1985) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query_old?uid=2985379&form=6&db=m&Dopt=r Peracchi M, Bamonti-Catena F, Lombardi L, Reschini E, Toschi V, Maiolo AT, Polli EE - "Plasma and urine cyclic nucleotide levels in patients with hyperthyroidism and hypothyroidism" Endocrinol Invest 6(3):173-7 (1983)
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