Barbara B. Tower

Preparation of 125I polypeptide hormones for radioimmunoassay using glucose oxidase with lactoperoxidase

Abstract The hydrogen peroxide-generating property of glucose oxidase was used in combination with the catalytic property of lactoperoxidase to radioiodinate polypeptide hormones with 125 -iodine. This rapid, gentle, enzymatic method reproducibly results in higher yields of iodinated hormones for use in radioimmunoassays.

Selective neuroendocrine effects of low-dose haloperidol in normal adult men.

The neuroendocrine effects of haloperidol, usually reported as side effects of this drug when given in antipsychotic doses, have not been systematically investigated. In the present study five normal adult men were administered saline and two doses of haloperidol (0.25 mg, 0.5 mg) intramuscularly in a double-blind randomized block design. The anterior pituitary hormones GH, LH, FSH, and PRL were measured in blood samples taken every 20 min for several hours thereafter.The low doses of haloperidol used have been shown by others to alter the human EEG; in our subjects these doses produced no objective or subjective clinical effects. There were no drug related changes in GH, LH, or FSH. PRL, however, showed a prompt, statistically significant, dose-related increase in plasma levels, with a return to baseline within 5h.Haloperidol has strong dopamine-blocking effects, and the hypothalamic inhibitory mechanism for PRL release is believed to be dopamine-mediated. The results of this study suggest that haloperidol may have utility in low doses primarily for its hypothalamic neuroendocrine effects, and that dose-related PRL release may be a useful paradigm for comparing dopamine-blocking antipsychotic agents in humans.

Radioimmunoassay of haloperidol in human serum.

Abstract Immunization of rabbits with a haloperidol hydrazone-bovine serum albumin conjugate elicited the formation of antibody to haloperidol. With this antiserum, concentrations of haloperidol as low as 1 ng/ml can be easily measured by radioimmunoassay of unextracted human serum. None of the known major metabolites of haloperidol displayed any significant cross-reactivity. Psychiatric patients receiving daily oral doses of 20 to 200 mg haloperidol had serum levels ranging between 5.8 and 245 ng/ml.

Secretion of hormones influencing water and electrolyte balance (antidiuretic hormone, aldosterone, prolactin) during sleep in normal adult men.

&NA; Renal conservation of electrolytes and water occurs normally during sleep. Antidiuretic hormone (ADH), aldosterone (ALDO), and prolactin (PRL) are hormones that may have interactive effects on kidney function. The availability of a radioimmunoassay for ADH as well as for ALDO and PRL permitted the study of the simultaneous secretion patterns of these three hormones during all‐night sleep in eight normal young adult men, by blood sampling every 20 min from 2300 to 0700 on two consecutive night. ADH, ALDO, and PRL all appeared to be secreted episodically. The pulsatile release of ADH was random, and average plasma ADH levels were unchanged during the night. ALDO and PRL, on the other hand, had an approximately 90‐min secretion rhythm, and average plasma concentrations of both hormones consistently increased during the hours of sleep. Average plasma sodium concentration was constant throughout the night. The nocturnal increase in plasma ALDO may be responsible for the normal reduction of urine sodium excretion during the night. The concomitant increase in plasma PRL might synergize with ALDO in influencing the renal retention of sodium, but PRL alone has little apparent effect on human kidney function. REM sleep‐related decreases in urine flow have been noted both in humans and in monkeys, but ADH secretion was not REM related in out subjects. Autonomic activation during REM is one possible explanation for decreased urine flow during this stage of sleep.

The talc-resin-TCA test: Rapid screening of radioionated polypeptide hormones for radioimmunoassay

Abstract The talc-resin-TCA test is a rapid, reliable method for predicting the behavior of 125I-hormones in radioimmunoassays (RIA). This test is based on the assessment of three different physicochemical properties of iodinated hormones: adsorption to talc, exclusion from ion exchange resin, and precipitation by TCA. These three parameters produce test patterns that are unique for monomeric 125I-hormone, aggregated 125I-hormone, and 125I-salts. Different iodination methods were used to prepare radioiodinated human and rat PRL, GH, TSH, and LH, and rat FSH. Purified monomeric 125I-hormones that gave reliable RIA results all showed a characteristic talc-resin-TCA profile of >90% talc adsorption, 90% TCA precipitation. This profile has successfully predicted reliable RIA results for 125I-hormones prepared from more than 80 iodinations.

Antidiuretic Hormone: Episodic Nocturnal Secretion in Adult Men

Nocturnal release of antidiuretic hormone (ADH) in eight young adult men occurred in a pulsatile, episodic fashion with no consistency from night to night in the same subject. There was no discernible relationship between ADH release and plasma sodium levels, sleep stages, or time of night.

[23] The Talc-resin-trichloroacetic acid test for screening radioiodinated polypeptide hormones

Publisher Summary This chapter discusses the use of talc-resin trichloroacetic acid test for screening radioiodinated polypeptide hormones. The talc-resin TCA test is a rapid, reliable physicochemical method for predicting the immunologic performance of 125 I-labeled hormones in radioimmunoassays (RIA). With the talc-resin TCA test, it is possible to anticipate the RIA behavior of 125 I -labeled human (h) and rat (r) prolactin (PRL), growth hormone (GH), thyroid-stimulating hormone (TSH), and luteinizing hormone (LH) prepared from more than 100 iodinations. The talc-resin TCA test is based on three different physicochemical properties of iodohormones: adsorption to talc, exclusion from resin, and precipitation by trichloroacetic acid (TCA). The test patterns are distinct for monomeric iodohormone, aggregated iodohormone, and 125 I-labeled salts. Thus, a usable iodohormone may be identified quickly and accurately by its meeting the criteria of greater than 90% talc adsorption, less than 25% bound to resin, and greater than 90% TCA precipitation. In addition, the talc and TCA percentages should agree within 3%. Radioiodinated human and rat PRL, TSH, GH, and LH have been prepared by different iodination procedures. All the purified monomeric iodohormones, producing sensitive and reliable RIA results, showed the characteristic talc-resin TCA test results of >90% talc adsorption, 90% TCA precipitation.

Antidiuretic hormone secretion during sleep in adult men

Publisher Summary Studies of nocturnal sleep EEG stages and plasma growth hormone (GH) and cortisol levels (used as indices of central nervous system (CNS) function) were performed in subjects with endogenous or exogenous elevation of plasma corticosteroid or ACTH levels, and in patients with hypothalamic tumors. These studies were designed to determine if there was any evidence of altered CNS function that was unique to Cushings disease, independent of any effects of hypercortisolemia per se. of the adrenal adenoma suggests, however, that cortisol excess also plays some role in the observed sleep EEG and GH changes. The presence of normal sleep EEG stages in 4 patients with Cushings disease who have subsequently developed Nelsons syndrome of 1-9 years duration additionally suggests a role of this peptide in the genesis of sleep EEG stages.