Abstract
Immunoreactive somatostatin (IRS) was identified in the male rat Harderian gland (HG) by radioimmunoassay. Tissue was extracted and a displacement curve performed; there were no significant differences between values obtained with serial dilutions of extracted tissue and those from purified somatostatin standard used in the radioimmunoassay. Basal values of HG-IRS were found to be in the nanomolar range (10.8±3.5 ng IRS/mg protein). Hypophysectomy did not change the HG-IRS but, in vivo growth hormone (GH) treatment led to a dramatic increase (6-7-fold) in the levels of IRS in the HG. Isoproterenol, a β-adrenergic agonist, when administered in vivo significantly decreased the HG-IRS content. The effect of two different calcium channel blockers on the isoproterenol-induced decrease of HG-IRS was studied; no changes were observed with nifedipine but verapamil, injected one hour after isoproterenol administration, prevented the drop in HG-IRS levels. These data demonstrate the existence of IRS in a new location, the rat Harderian gland, and support a classical endocrine regulation for its tissue concentration.
Original language | English (US) |
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Pages (from-to) | 571-574 |
Number of pages | 4 |
Journal | Peptides |
Volume | 9 |
Issue number | 3 |
DOIs | |
State | Published - 1988 |
Keywords
- Beta-adrenergic agonists
- Calcium channel blockers
- Growth hormone
- Harderian gland
- Somatostatin
ASJC Scopus subject areas
- Biochemistry
- Physiology
- Endocrinology
- Cellular and Molecular Neuroscience