Effects of osmotic pressure and somatostatin on the cAMP messenger system of the osmosensitive prolactin cell of a teleost fish, the tilapia (Oreochromis mossambicus)
| Autor: | Russell J. Borski, E. Gordon Grau, Lisa M.H. Helms |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
endocrine system medicine.medical_specialty IBMX Biology Second Messenger Systems Prolactin cell chemistry.chemical_compound Endocrinology Osmotic Pressure Pituitary Gland Anterior 1-Methyl-3-isobutylxanthine Internal medicine Cyclic AMP medicine Animals Osmotic pressure Forskolin Colforsin Euryhaline Prolactin Perciformes Kinetics Somatostatin chemistry Animal Science and Zoology hormones hormone substitutes and hormone antagonists Endocrine gland |
| Zdroj: | General and Comparative Endocrinology. 83:111-117 |
| ISSN: | 0016-6480 |
| Popis: | Altered osmotic pressure and somatostatin (SRIF) rapidly alter prolactin (PRL) release from the pituitary gland of the euryhaline teleost, the tilapia. The present studies were undertaken to determine whether altered osmotic pressure and SRIF influence cAMP metabolism in a manner that is correlated with the pattern of PRL release observed previously. Although PRL release is stimulated within 10-20 min when medium osmotic pressure is reduced, cAMP metabolism was not altered. However, following 1 hr of incubation in the presence of IBMX, cAMP accumulation was higher in PRL tissue exposed to medium of reduced osmotic pressure. This suggests that cAMP does not initiate an increase in PRL release in response to reduced osmotic pressure. By contrast, SRIF reduced the forskolin-stimulated increase in cAMP levels in a manner consistent with its rapid effects on PRL release. Moreover, the ability of SRIF to suppress the forskolin-stimulated increase in cAMP levels suggests that SRIF may act to render adenylate cyclase less responsive to direct stimulation by forskolin. |
| Databáze: | OpenAIRE |
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