The experiments were carried out on 60 mature male guinea-pigs, randomly allocated into six groups. Animals from Group I (control) received intracardiac injections of 0.25 cm3 0.9% NaCl, while animals from all other groups received intracardiac injections of histamine after the intraperitoneal application of H1, H2 and muscarinic receptor blockers. The thyroids. adrenals, parotid glands and pancreas were collected. The levels of cAMP in the homogenates of all these glands, adrenaline in the adrenal glands, thyroxine and triiodthyronine in the thyroid glands and alpha-amylase in the pancreas and in the parotid glands were studied. Moreover, histological stainings and histochemical reactions were done for colloid in the thyroid glands, for adrenaline in the adrenals and for zymogen in the parotid glands and pancreas. The results suggest that histamine causes non-selective. H1-dependent secretion of thyroxine and triiodthyronine. selective, H1-dependent secretion of adrenaline and selective, H2-dependent secretion of alpha-amylase, without the participation of muscarinic receptors.
Adrenal Glands Animals