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Nuclear proteins of the human peripheral blood T lymphocytes that bind to the CREs located within three 21-bp repeat enhancers of the HTLV-I promoter belong to the CREB/CREM family of bZIP transcription factors. It has been shown previously that Tax enhances transactivation of these CREs by direct interactions with the bZIP domain of the transcription factors to stabilize DNA-binding. We show that CREB and CREM bind all three CRE sequences of the HTLV-I promoter which are important determinants in Tax-elicited transactivation as well as PKA-mediated activation of the HTLV-I promoter. Tax and PKA activate transcription from a HTLV-I-LTR CAT reporter plasmid transfected to NIH 3T3 cells, and CREM attenuates the activation. In the context of a GAL4 CREB fusion protein in which the DNA-binding bZIP domain of CREB is replaced by GAL4 binding domain, a single amino acid substitution of serine-133, phosphorylated by PKA and critical for the transactivation function of CREB, attenuates both Tax and PKA-mediated transcriptional responses. These observations suggest that Tax enhances CREB-mediated transactivation of the HTLV-I promoter by a mechanism apart from, and/or in addition to, the reported stabilization of DNA-binding by interaction with the bZIP domain of CREB.

An 8-15S RNA fraction from calf parathyroid glands stimulated the incorporation of radioactive lysine and methionine into protein by 15- to 30-fold in a wheat germ extract. The major product, representing 25% of the total protein synthesized, could be bound to an antiserum to parathyroid hormone and binding was inhibited by parathyroid hormone. The chromatographic mobilities of the two tryptic peptides of the cell-free product that contained methionine were identical to the corresponding peptides of parathyroid hormone. Upon electrophoresis in acidic or sodium dodecyl sulfate-acrylamide gels, the cell-free product migrated more slowly than either parathyroid hormone or its biosynthetic precursor, proparathyroid hormone. Analysis of cyanogen bromide products indicated that the cell-free product contained an additional sequence of amino acids at the amino-terminal end. A protein corresponding to the cell-free product could not be detected in intact cells even during incubations with [3H]leucine as short as 2 min, which suggests the protein may be a transient precursor to proparathyroid hormone.

DNA complementary in sequence to the messenger RNA for pre-proparathyroid hormone was synthesised using reverse transcriptase. In a linked transcription–translation system using RNA polymerase and cell-free extract from wheat germ, the DNA directed the synthesis of a protein identified as pre-proparathyroid hormone by N-terminal Sequencing and by electrophoretic and immunologic criteria.

A relatively simple, standardized 6 1/2 hour water deprivation test is described which adequately differentiates disorders of the neurohypophyseal-hypothalamic system from primary polydipsia. Normal subjects are characterized by an initial serum osmolality between 273 and 293 milliosmoles (mOsm) per kilogram by remarkable constancy of the serum osmolality throughout the 6 1/2 hours and by a urine-to-serum osmolality ratio of 1.9 or greater. Individuals with diabetes insipidus show loss of this homeostatic mechanism to a variable degree. All patients with diabetes insipidus demonstrate defective urinary concentrating capacity. Those patients with diabetes insipidus severe enough to require vasopressin therapy invariably show serum osmolar concentrations of 300 mOsm/kg or greater by the end of the test. Individuals with primary polydipsia demonstrate stability of serum osmolality at normal or slightly below normal levels, while urinary osmolality at the end of the test period is within normal limits.

PITUITARY ABLATION by stereotactic transnasal Yttrium Y 90 implantation has been carried out at this institution in a number of patients with advanced metastatic mammary carcinoma.1 The occurrence of subsequent water intoxication and the ultimate degree of diabetes insipidus varied from case to case, indicating that the interruption of the hypothalamico-hypophyseal system was frequently incomplete.2 The question is: Are these disturbances determined by the degree of pituitary damage or by the degree of retrograde loss of hypohyponeurons, or both?In the present study an attempt was made to correlate diabetes insipidus with hypothalamic damage by assessing the degree of nuclear and neuronal atrophy occurring in the supraoptic (SON) and paraventricular (PVN) nuclei of five patients who died from 5 to 20 months following Yttrium Y 90 hypophysectomy and in whom both anterior and posterior pituitary function had been studied preoperatively and postoperatively. Estimates of degree of

Biosynthesis of a precursor to bovine parathyroid hormone has been demonstrated in slices of parathyroid tissue incubated in vitro. The proparathyroid hormone is 15-20 amino acids larger than the bovine hormone, and has a molecular weight of about 11,500 as determined by polyacrylamide gel electrophoresis. Upon incubation of parathyroid slices with [14C]aminoacids, radioactivity is detected initially in the precursor. If incorporation of [14C]aminoacids is inhibited after a short incubation either by replacement of radioactive amino acids with unlabeled amino acids or by addition of puromycin, the amount of radioactivity in the precursor decreases, while the radioactivity in the hormone continues to increase. The precursor is bound by an antibody that is specific for parathyroid hormone, and its binding can be inhibited by addition of the hormone. Analysis of tryptic digests indicates that the precursor and the hormone have common tryptic peptides, and that there are at least two additional peptides in the precursor.

Gel filtration and radioimmunoassay were used to determine the molecular size and immunochemical reactivity of parathyroid hormone present in gland extracts, in the general peripheral circulation, and in parathyroid effluent blood (obtained by venous catheterization) from patients with hyperparathyroidism, as well as from calves and from cattle. Hormone secreted in vivofrom normal bovine parathyroid glands and from human parathyroid adenomas is similar in size to the 84-amino-acid peptide (molecular weight of 9500) extracted from the parathyroids. However, much of the immunoreactive parathyroid hormone present in the peripheral circulation of man and cattle is smaller than the extracted or secreted hormone; it elutes from gel columns at a position corresponding to a molecular weight of about 7000. The immunological characteristics of extracted and secreted hormone are identical, while hormone in the general circulation is immunologically dissimilar to extracted and secreted hormone. The results indicate that parathyroid hormone secreted from the parathyroids in man and cattle is at least as large as the molecule extracted from normal bovine glands. However, once secreted into the circulation the hormone is cleaved, and one or more fragments, immunologically dissimilar to the originally secreted hormone, constitute the dominant form of circulating immunoreactive hormone.