AJP - Endocrinology and Metabolism, Vol 253, Issue 1 E6-11, Copyright © 1987 by American Physiological Society
Static mechanical properties of lungs from adrenalectomized pneumonectomized rats
R. A. Bennett, J. L. Addison and D. E. Rannels
The pressure-volume characteristics of saline-filled lungs of adult rats
were studied after left pneumonectomy (PNX), with or without prior
bilateral adrenalectomy (ADX). Male Sprague-Dawley rats (200-240 g)
remained unoperated (UNOP) or were divided into three surgical groups: left
PNX, ADX alone, or PNX preceded 5 days earlier by ADX (ADX/PNX). Two weeks
post-PNX, maximum lung volumes [MLV; measured at transpulmonary pressure
(Ptp) of 10 cmH2O] of right lungs from PNX and ADX/PNX rats remained 20 and
37% below UNOP values, respectively, although right lung mass was equal to
or exceeded that of both lungs in UNOP controls. Four weeks postoperative,
MLVs approached but remained below normal values. In the ADX/PNX group, MLV
was 35% below that predicted for lung mass. The effects of ADX on both lung
mass and MLV were blocked by daily injections of ADX/PNX animals with
hydrocortisone acetate (5 mg/kg). Neither PNX nor ADX/PNX altered lung
volume at zero Ptp or changed the concentration of lung collagen or
elastin. When corrected for differences in MLV, relative tissue compliance
was unaffected by PNX but was reduced by ADX/PNX. These results indicate
that MLV is not restored in parallel with lung mass during the rapid phase
of compensatory tissue growth, which follows partial pneumonectomy, and
that this discrepancy is accentuated by adrenalectomy.
