摘要:

Primary cultures were prepared from ovaries of immature rats that had been superovulated. The dispersed luteal cells attached to growth surfaces, formed monolayers and secreted progesterone. Progesterone accumulation in the medium was most pronounced in the first week of culturing. Removal of serum from the medium resulted in a progressive decline in progesterone concentration in the culture medium which reached basal levels by 5 hours. In medium without serum, the addition of hCG, FSH or prolactin stimulated an increase in progesterone secretion within 1 hour. Also cholera toxin stimulated a significant increase in progesterone levels in the medium. Prior exposure of cultures to estradiol for 3 days did not augment the response to hCG and inhibited the ability of cholera toxin to stimulate progesterone secretion. These results indicate that the steroidogenic function of rat luteal cells can be studied in culture and that a number of hormones rapidly stimulate the secretion of progesterone from these cells.

ISSN:0743-5800    

DOI:10.1080/07435808609023650

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The recombinant DNA-derived 20,000-dalton variant of N-terminal methionyl human growth hormone (20K-Met-hGH) had a hyperglycemic effect in fasted dogs when injected 11 hours prior to an oral glucose tolerance test (OGTT). These results reported here suggest that 20K-Met-hGH can induce glucose intolerance in dogs similar to that produced by recombinant DNA-derived 22,000 dalton N-terminal methionyl human growth hormone (22K-Met-hGH) and the normal pituitary-source human growth hormone (22K-hGH).

ISSN:0743-5800    

DOI:10.1080/07435808609023651

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

125I-Triac was employed to measure hepatic thyroid hormone nuclear receptor (RT) in the rat. The binding properties of 125I-Triac and 125-T3 were compared in a 0.4 M KCl extract of a liver nuclear preparation. The order in which the stable compounds, Triac, T3, T4and rT3, competed for125I-Triac and125I-T3binding in liver nuclear extract was similar (Triac>T3>T4>rT3), suggesting association of both radioligands with RT. Scatchard plot analysis of specific125I-Triac and125I-T3binding in nuclear extract gave approximately equal estimates of the maximum binding capacity (MBC). However, the binding affinity, as represented by the equilibrium association constant (KA), was higher for125I-Triac than for125I-T3 (7-10×109M−1vs 1-3×109M−1). To determine the effect of contaminating serum proteins on estimates of MBC and KA, a small amount of dilute rat serum was added to the same nuclear extract preparation. Addition of serum decreased the KAvalue and markedly increased the MBC values estimated by analysis of125I-T3binding data. In contrast, KAand MBC values derived from125I-Triac binding data were not influenced appreciably by the addition of serum. These data indicate that: 1) both125I-Triac and125I-T3bound to RT in rat liver nuclear extract, 2) the affinity of RT for125I-Triac is appreciably greater than for125I-T3, and 3) estimates of RT concentration (MBC) made with125I-Triac are less sensitive to serum protein contamination than those made with125I-T3. These properties of125I-Triac may be useful in efforts to demonstrate RT in tissues that have low RT levels and/or when serum contamination is present.

ISSN:0743-5800    

DOI:10.1080/07435808609023652

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The clinical utility of the urinary cyclic AMP:creatinine ratio in assessing parathyroid function was evaluated in 33 hyper-calcemic patients and compared this with the determination of the renal component of urinary cyclic AMP. We found the discriminatory value of urinary cyclic AMP:creatinine ratio to be slightly superior and to have additional advantages. Not only did the urinary cyclic AMP:creatinine ratio show empirically somewhat better discrimination between normals and patients with primary hyperparathyroidism, but it is technically simpler than the determination of the nephrogenous cyclic AMP. Our urinary cyclic AMP excretion data show 90% discrimination of primary hyperparathyroid subjects from normals. Among all hypercalcemic patients studied who had both elevated urinary cyclic AMP and elevated parathyroid hormone (PTH) levels by radioimmunoassay (RIA), 77% had primary hyperparathyroidism, and 23% had malignancy-associated hypercal-cemia. Of those patients with malignant tumors and hypercalcemia, half had elevated urinary cyclic AMP and two thirds had elevated PTH by RIA. These data suggest that these tests have little discriminatory value in differentiating primary hyperparathyroidism from malignancy-associated hypercalcemia. No hypercalcemic patient who had both serum PTH and urine cyclic AMP in the normal range was found to have primary hyperparathyroidism. This suggests that further observation and evaluation is indicated in such patients before exploratory surgery is undertaken.

ISSN:0743-5800    

DOI:10.1080/07435808609023653

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

These studies were designed to examine the effects of extracellular calcium ion (Ca++) concentration upon basal and dibutyryl (db) cAMP or potassium ion (K+)-stimulated release of growth hormone (GH) and to determine whether increased extracellular Ca++can overcome somatostatin (SRIF) -inhibited release of stored rGH in parallel with its reported effect upon SRIF inhibition of stimulated insulin and glucagon release. Experiments were performedin vitrousing prelabeled rat pituitary fragments in a perifusion, specific immunoprecipitation system designed to limit observations to release of stored hormone from viable cells. Increased (up to 5.4 mM) extracellular Ca++inhibits basal and dbcAMP-stimulated release of stored, prelabeled [3H]rGH in parallel with the effects of SRIF: post-inhibition rebound, dose responsivity, and differential effect upon early and late dbcAMP-stimulated release of stored [3H]rGH. Increased (21 mM) extracellular K+interferes with both Ca++-and SRIF-inhibited early dbcAMP-stimulated release of stored [3H]rGH. The combination of increased extracellular Ca++and SRIF inhibits basal release of stored [3H]rGH more than either agent alone and during dbcAMP stimulation, rebound release of stored [3H]rGH follows withdrawal of either inhibitor despite continuation of the other. This rebound release is enhanced when both inhibitors are withdrawn simultaneously. Conclusions: (a) the inhibition of stored rGH release induced by increased extracellular Ca++and SRIF occurs through at least partially independent mechanisms, and (b) increased extracellular Ca++does not reverse SRIF inhibition of stimulated rGH release from prelabeled intracellular storage, in contrast with observations in the pancreatic islet.

ISSN:0743-5800    

DOI:10.1080/07435808609023654

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Synthetic galanin, infused at a rate of 4μg/kg body weight/h for 30 min, elicited a mild but significant hyperglycemia in conscious dogs and a fall in plasma insulin. Pancreatic glucagon, epinephrine, norepinephrine, cortisol and growth hormone levels were not affected significantly. The mild hyperglycemic action of galanin seems to be due to an inhibition of insulin production. Thus galanin appears to be involved in glucose homeostasis.

ISSN:0743-5800    

DOI:10.1080/07435808609023655

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

ISSN:0743-5800    

DOI:10.1080/07435808609023656

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

ISSN:0743-5800    

DOI:10.1080/07435808609023657

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor