Thyroid: Serum Radioiodide Concentration Ratio During the Estrous Cycle of the Mouse

Abstract

period of 2-2vi minutes to account for the plasma clearance curves of Fig. 2 solely on the basis of redistribution. This rapid rate of clearance, even after the inhibition of amine-metabolizing enzymes. is compatible with the observation that circulating catecholamines are taken up quickly by many tissues of the body(3,6).S U~V Z Q~~. The simultaneous inhibition of catechol-0-methyl transferase and monoamine oxidase (by pyrogallol and JB-835) produced only moderate prolongation of the cardiovascular effects of injected I-norepinephrine in anesthetized dogs. This prolongation of pharmacological action in presence of enzyme inhibitors was correlated with a delayed disappearance of injected norepinephrine f roni the circulation. While these results indicate that nietabolisni by these enzymes contrib-u tes to removal of circulating norepinephrine from the plasma in the dog, they further suggest that the physiological inactivation of circulating norepinephrine at the receptor sites does not require metabolic destruction of the amine by these enzymes.I am grateful to Dr. Leon Goldberg for advice and to Mrs. Frances DeCosta for technical assistance.

The relationship between ovulation and the changes in thyroid gland activity that occur during the oestrous cycle in rats, mice and hamsters

“…Uptake of 131I is reported as being highest in animals in 'late pro-oestrus'. Boccabella & Alger (1961) took smears for five or more days and state that only animals that were cycling were used, though they do not say how they determined this. 'Only mice whose vaginal smears could be identified unequivocally as typical of one of the five stages of the oestrous cycle (pro-oestrus, early oestrus, late oestrus, metoestrus and dioestrus) were used in the experiments', but the criteria on which recognition was based are not given and no mention is made of the state of the ovaries, oviduct or uterus.…”