Adrenal Catecholamine Content: Effects of Congenital GH, PRL and TSH Deficiency and of Hormone Replacement Therapy in the Male Mouse

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Abstract
The content of epinephrine (E), norepinephrine (NE) and dopamine (DA) was measured in the adrenals of male Snell dwarf mice, which are characterized by a genetically determined lack of growth hormone (GH), prolactin (PRL) and thyrotropin (TSH), and in normal male mice of the same strain. Additionally, adrenal catecholamine (CA) content of both normal and dwarf mice was determined after 6-day treatment with TSH, GH or PRL. Although the adrenal E content (in saline-, TSH- and PRL-treated groups) and DA content (in saline- and PRL-treated groups) of dwarf mice were significantly lower than those observed in respective groups of normal animals, such differences were not found for NE. The latter finding suggests the presence of a much higher adrenal NE concentration in dwarf mice, since their adrenal glands are several-fold smaller than those of phenotypically normal mice. It is suggested that the increased concentration of NE in dwarfs is related to the reduced activity of an enzyme, phenylethanolamine-N-methyl transferase (PNMT), which converts adrenal NE into E. Moreover, it was demonstrated that GH treatment resulted in abolition of the differences in adrenal E, NE and DA content between normal and dwarf mice. The mechanism of this effect of GH remains unclear.