The effects of moderate protein deficiency on beta-adrenoceptor density in rat parotid and submandibular salivary glands.
The effects of moderate protein deficiency on the number and dissociation constant of beta-adrenergic receptors were investigated. One group of adult rats was fed a protein-deficient diet (5% protein), a control group was given a similar diet with 20% protein, and a third group was fed a standard pellet diet. After 21 days, the salivary glands were removed and the cell membranes were isolated. The binding of [3H]-dihydroalprenolol to cell membranes was measured, with or without the presence of timolol, a potent beta-adrenoceptor antagonist. The rats fed the 5% protein diet had fewer beta-adrenoceptors in both the parotid and the submandibular glands than did the 20% protein group, which did not differ from the standard pellet group. The dissociation constant was not affected by protein deficiency. The rats fed the 5% protein diet had a significantly lower gain in body weight, less heavy submandibular glands but heavier parotids than the rats fed 20% protein. Thus the cellular conditions for protein secretion in the salivary glands are impaired during moderate protein deficiency in the adult rat.
Johannsson
I
I
Department of Cariology, University of Umeå, Sweden.
Ryberg
M
M
D000818:Animals; D004082:Dihydroalprenolol / Q000494:pharmacology; D006984:Hypertrophy; D008297:Male; D009929:Organ Size; D010306:Parotid Gland / Q000737:chemistry* / Q000473:pathology; D011488:Protein Deficiency / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000032:analysis* / Q000187:drug effects; D013363:Submandibular Gland / Q000737:chemistry* / Q000473:pathology; D013999:Timolol / Q000494:pharmacology; D014316:Tritium
D011943:Receptors, Adrenergic, beta; D014316:Tritium; D004082:Dihydroalprenolol; D013999:Timolol