Tyrosine hydroxylase and dopamine beta-hydroxylase inductions evoked by reserpine in the superior cervical ganglion of developing eu- and hypothyroid rats.
This study was designed to determine the effect of neonatally-produced hypothyroidism on reserpine-elicited tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (D beta H) induction in the superior cervical ganglion (SCG) in rats. Some rats were rendered hypothyroid from birth by daily treatment with propylthiouracil (PTU). Some hypothyroid rats received replacement therapy with triiodothyronine (T3). Some rats received PTU for 20 days, beginning at 90 days of age. Some rats were not treated and served as controls. TH and D beta H activities were assayed at 30, 50 and 110 days of age. Basal TH activity in the SCG for rats made hypothyroid as neonates was significantly lower than for controls at all ages tested; basal D beta H activity for these rats was lower than for controls at 30 and 50 days of age, but by 110 days was not different from that for controls. Basal TH activity for rats made hypothyroid as adults was intermediate between that for controls and rats made hypothyroid from infancy. Injecting control rats with reserpine produces a robust TH induction in the SCG at each age tested, and a strong D beta H induction at 50 and 110 days of age. Reserpine-evoked TH and D beta H inductions in rats made hypothyroid as adults were not different from those seen in controls. In contrast, rats made hypothyroid from infancy showed virtually no evidence of a reserpine-provoked TH or D beta H induction at any age tested. TH and D beta H inductions for hypothyroid rats given T3 replacement were completely normal.(ABSTRACT TRUNCATED AT 250 WORDS)
Laboratoire d'Endocrinologie, Université Paris XI, Orsay, France.
A
A
de Lonlay
M F
MF
Blouquit
M
M
Valens
N
N
Chami
D A
DA
Edwards
D
D
Gripois
D000375:Aging / Q000378:metabolism*; D000818:Animals; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism*; D005728:Ganglia, Sympathetic / Q000201:enzymology*; D007037:Hypothyroidism / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012110:Reserpine / Q000494:pharmacology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D012110:Reserpine; D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase