We studied the effect of thyroid hormones on the postnatal development of the gas exchange region of rat lungs. Treatment with triiodothyronine (T3, 0.1 microgram . g body wt-1 . day-1) accelerated the increase of the surface-to-volume ratio (S/V) and surface area (Sa) and decrease of the mean chord length (Lm) of the gas exchange structures of pups killed at age 7 days. Propylthiouracil (PTU, 100 micrograms twice daily) from age 1 to 13 days, with death at age 14 days, diminished the rise of S/V and Sa and the fall of Lm compared with diluent-injected pups. Providing drinking water with 0.01% PTU to dams from gestation day 20 (term 22 days) to postnatal day 14 also diminished the rise of S/V and fall of Lm. Treatment of pups nursed by dams drinking 0.01% PTU with thyroxine (0.1 microgram/g body wt) every other day from age 1 to 13 days significantly diminished the effect of PTU on S/V, Sa, and Lm. We conclude thyroid hormones can modulate the postnatal architectural development of the gas exchange region of the rat lung.
- Copyright © 1986 the American Physiological Society